Relationship between respiratory muscle function and age, sex, and other factors

Influence of physical exercise on respiratory muscle function in older adults: A systematic review and meta-analysis

Respiratory function decreases with aging. The literature showed that non-ventilatory specific exercise could have a positive impact on respiratory muscles. A systematic literature review was conducted to assess the effects of non-ventilatory specific exercise on maximal inspiratory (MIP) and expiratory pressure (MEP) and peak expiratory flow (PEF) in older adults. The included 9 trials investigated the effects of resistance training, yoga, Pilates, physical activity based on walking, and whole-body vibration training. The meta-analysis showed no statistically significant differences in MIP, MEP, and PEF after implementation of a non-ventilatory specific exercise program in older individuals. Between-study heterogeneity was substantial for MIP and MEP outcomes but it was not statistically significant for PEF. Further RCTs will be necessary to determine the effects of physical exercise interventions. PROSPERO registry CRD42023478262.

Joint association of sedentary behavior and physical activity with pulmonary function

BACKGROUND

Sedentary behavior may influence the respiratory health, but the joint effects of sedentary behavior and physical activity on pulmonary function remains poorly elucidated. We aimed to estimate the association between sedentary behavior and physical activity with pulmonary function.

METHODS

A total of 12,343 participants aged 12-79 years were analyzed from the U.S. NHANES 2007-2012. Participants were categorized into 16 groups according to the cross-tabulation of sedentary behavior time (0-4.0, 4.1-8.0, 8.1-12.0, and > 12.0 h/day) and moderate or vigorous physical activity (MVPA) (0, 1-149, 150-299, and ≥ 300 min/week). Generalized linear models were used to test the association of sedentary behavior and MVPA with pulmonary function.

RESULTS

Participants with sedentary behavior > 4.0 h/day were negatively related to FEV1 (forced expiratory volume in 1 s) (β ranging from -0.015 to -0.009, p < 0.05). Compared with the reference group (0 min of MVPA and > 12.0 h/day of sedentary behavior), the negative association of sedentary behavior ≤ 8.0 h/day with FEV1 may be reduced through appropriate MVPA (β ranging from 0.019 to 0.030, p < 0.05). For sedentary behavior > 8.0 h/day, even MVPA ≥ 300 min/week may not decrease the negative relationships. Similar results were also observed in FVC (forced vital capacity) (β ranging from 0.018 to 0.030, p < 0.05). In participants aged ≥ 45 years, the associations were more notable.

CONCLUSION

This study indicated the sedentary behavior ≤ 4.0 h/day was a relatively healthy lifestyle for pulmonary function. Only below 8.0 h/day of sedentary behavior, the negative association with pulmonary function may be reduced through appropriate MVPA.

Respiratory Movements at Different Ages

Background and Objectives: The current study aimed to better understand the changes in respiration that occur with aging in men and women to provide accurate recommendations for breathing exercises to improve health. Materials and Methods: A total of 610 healthy subjects, aged 20 to 59, participated in the study. They performed quiet breathing while wearing two respiration belts (Vernier, Beaverton, OR, USA) at the height of the navel and at the xiphoid process to record abdominal motion (AM) and thoracic motion (TM), respectively. Vital capacity, representing maximal inhalation movement, was measured using a spirometer (Xindonghuateng, Beijing, China). After exclusion, 565 subjects (164 men, aged 41 ± 11; 401 women, aged 42 ± 9) were included for statistical analysis using the Kruskal-Wallis U test and stepwise multiple linear regression. Results: Abdominal motion and its contribution to spontaneous breathing were significantly larger for older men, while the contribution of thoracic motion was smaller for older men. There was no significant difference in thoracic motion between the younger and older men. The differences in women's respiratory movements among various ages were mild and negligible. The contribution of thoracic motion to spontaneous breathing in women was larger than in men for those of older ages (40-59 years), but not for those of younger ages (20-39 years). Additionally, men's and women's vital capacities were less in those of older ages, and the men's were larger than the women's. Conclusions: The findings indicate that men's abdominal contribution to spontaneous breathing increased from 20 to 59 years of age due to increased abdominal motion. Women's respiratory movements did not change much with aging. The maximal inhalation movement became smaller with aging for men and women. Healthcare professionals should focus on improving thoracic mobility when addressing health concerns about aging.

Relationship between inspiratory muscle strength and balance in women: A cross-sectional study

BACKGROUND

There is scarce evidence on changes at the functional level associated with the respiratory area in women. This study aims to analyse the relationship between inspiratory muscle strength and balance in women.

MATERIAL AND METHODS

In this cross-sectional observational study, the sample consisted of groups according to the results obtained in the balance test. Inspiratory muscle weakness was defined as maximum inspiratory pressure (MIP) ≤ 80% of the predictive value. MIP was carried out using through a mouthpiece, with an electronic manometer. Logistic regression model was used to examine if MIP predicts balance.

RESULTS

159 women participated in the study. Approximately 20% of them achieved balance ≤ 2 seconds and 18% presented MIP≤80%. MIP was associated with the time achieved in the one-leg support test. Subjects with MIP ≤ 80% of the predictive value show 3 times more risk of having a lower performance in the balance test (OR = 3.26).

CONCLUSIONS

Inspiratory muscle weakness is associated with deficient balance in this sample. It shows the need for multidimensional assessment and rehabilitation strategies for patients identified as having MIP weakness and/or balance disorders.

Pulmonary function is associated with frailty, hospitalization and mortality in older people: 5-year follow-up

BACKGROUND

The relationship between pulmonary impairment and frailty has rarely been studied in community-dwelling older adults.

OBJECTIVE

This study aimed to analyze the association between pulmonary function and frailty (prevalent and incident), identifying the best cut-off points to detect frailty and its association with hospitalization and mortality.

METHODS

A longitudinal observational cohort study with 1188 community-dwelling older adults was taken from the Toledo Study for Healthy Aging. The forced expiratory volume in the first second (FEV₁) and the forced vital capacity (FVC) were measured with spirometry. Frailty was evaluated using the Frailty Phenotype and Frailty Trait Scale 5. Associations between pulmonary function and frailty, hospitalization and mortality in a 5-year follow-up and the best cut-off points for FEV₁ and FVC were analyzed.

RESULTS

FEV₁ and FVC were associated with frailty prevalence (OR from 0.25 to 0.60), incidence (OR from 0.26 to 0.53), and hospitalization and mortality (HR from 0.35 to 0.85). The cut-off points of pulmonary function identified in this study: FEV1 (≤1.805 L for male and ≤1.165 L for female) and FVC (≤2.385 L for male and ≤1.585 L for female) were associated with incident frailty (OR: 1.71-4.06), hospitalization (HR: 1.03-1.57) and mortality (HR: 2.64-5.17) in individuals with and without respiratory diseases (P < 0.05 for all).

CONCLUSION

Pulmonary function was inversely associated with the risk of frailty, hospitalization and mortality in community-dwelling older adults. The cut-off points for FEV₁ and FVC to detect frailty were highly associated with hospitalization and mortality in the 5-year follow-up, regardless of the existence of pulmonary diseases.

Accuracy of handgrip and respiratory muscle strength in identifying sarcopenia in older, community-dwelling, Brazilian women

Certain cut-off points for sarcopenia screening and diagnosis are arbitrary and based on European populations, with normative references often obtained from healthy young adults. Although respiratory skeletal muscle strength tests represent low-cost clinical measures commonly performed in clinical practice by health professionals, a gap remains regarding whether respiratory skeletal muscle strength tests are adequate and sensitive measures for sarcopenia screening. This study aimed to verify the value of handgrip and respiratory muscle strength as possible discriminators to identify sarcopenia and to establish cut-off points for sarcopenia screening in community-dwelling, Brazilian women. In a cross-sectional study, 154 community-dwelling, Brazilian women (65-96 years) were assessed for appendicular skeletal muscle mass, handgrip (HGS), and respiratory muscular strength, including maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP). The data were analyzed using the ROC curve and the Youden Index determined cut-off points. Statistical significance was set at 5%. 88 participants (57%) were sarcopenic. MEP (OR 0.98 [95%CI 0.97, 1.00], p = 0.023) and HGS (OR 0.82 [95% CI 0.75, 0.90], p < 0.001) were independent factors for sarcopenia in older. The optimal cut-off points for identifying sarcopenia were ≤ 77 cmH₂O for MEP (AUC = 0.72), and ≤ 20 kg for HGS (AUC = 0.80). Simple muscular strength tests, including HGS and MEP, may be considered in the identification of sarcopenia in older, community-dwelling, Brazilian women. Future work is still needed to assess external validation of the proposed cut-offs before the clinical application.

Comparison of international and Japanese predictive equations for maximal respiratory mouth pressures

Respiratory muscle weakness has attracted attention because sarcopenia and respiratory muscle dysfunction may play a key role in the development of respiratory failure. To evaluate respiratory muscle strength appropriately, individual factors such as sex, age, body size, and ethnicity should be considered. This study aimed to compare equations available in Japan and other countries for predicting respiratory muscle strength. We tested 21 equations for maximal inspiratory pressure (MIP) and 17 for maximal expiratory pressure (MEP) for each sex (76 equations in total) in 159 normal, healthy subjects. We observed wide variations in the overall agreement among the MIP and MEP equations. Some equations showed a proper normal distribution, with median values of almost 100%, and the Japanese equations released in 1997 generally showed the best distributions of both %MIP and %MEP. We can conclude that it is better to use Japanese equations when evaluating respiratory muscle strength in Japanese subjects.

Nocebo Effects of Clinical Communication and Placebo Effects of Positive Suggestions on Respiratory Muscle Strength

Introduction:

The effects of specific suggestions are usually studied by measuring parameters that are directly addressed by these suggestions. We recently proposed the use of a uniform, unrelated, and objective measure like maximal muscle strength that allows comparison of suggestions to avoid nocebo effects and thus to improve communication. Since reduced breathing strength might impair respiration and increase the risk of post-operative pulmonary complications, the aim of the present study was to evaluate the effects of the suggestions on respiratory muscle power. Both the identification and neutralization of negative suggestions in the clinical context and stimulating suggestions could improve breathing force, a predictor of physical fitness and convalescence.

Methods

In 50 healthy, adult volunteers, respiratory muscle strength was measured by maximal inspiratory and expiratory pressures, as well as by maximal inspiratory and expiratory flows. Baseline was compared to values after application of eleven suggestions, five out of clinical context, including memory of negative or positive past, risk information for informed consent, and a non-verbal suggestion. Six stimulating suggestions included self-affirmation, empowering words, a heroic mirror image, and an imagination.

Results

All suggestions showed an impact on respiratory muscle strength, indicating placebo and nocebo effects. No single parameter could represent the breathing force in its complexity, however, trends and different specific aspects of it were measured. The strongest reaction was observed with the recall of a previous negative situation resulting in a reduction in expiratory flow to 96.1% of baseline (p = 0.041). After risk information, a decrease was observed in three of the parameters, with the highest extend in expiratory pressure by 4.4%. This nocebo effect was neutralized by adding positive aspects to the risk information. Every intended strengthening suggestion resulted in statistically significant increases of at least one parameter, with changes of up to 10% (e.g., MEP 110.3%, p = 0.001), indicating placebo effects. Here, expiration was more affected than inspiration. Sex was the only influencing factor reaching statistical significance, with stronger reactions in women.

Conclusion

Respiratory muscle strength proved to be sensitive to suggestions with clinical context, as well as suggestions intended for stimulation. With this objective measurement, evaluation, and comparison of different suggestions is possible to help avoid nocebo effects. The demonstrated effect of supporting suggestions can be followed up and used in clinical practice.

Sarcopenia is not associated with inspiratory muscle strength but with expiratory muscle strength among older adults requiring long-term care/support

BACKGROUND

Recently, the concept of respiratory sarcopenia has been advocated, but evidence is lacking regarding which respiratory parameters are appropriate indicators. Therefore, we investigated the association between sarcopenia, respiratory function, and respiratory muscle strength to identify the most appropriate parameters for respiratory sarcopenia.

METHODS

We included 124 older adults (67 men, 57 women; average age 77.2 ± 8.3 years) requiring long-term care/support who underwent Day Care for rehabilitation. Handgrip strength, usual gait speed, and skeletal muscle mass were measured using bioelectrical impedance analysis. Participants were then diagnosed with sarcopenia using the algorithm of the Asian Working Group for Sarcopenia 2019. Parameters of respiratory function (forced vital capacity, forced expiratory volume in one second [FEV1.0], FEV1.0%, and peak expiratory flow rate) and respiratory muscle strength (maximal expiratory pressure [MEP] and maximal inspiratory pressure) were also measured according to American Thoracic Society guidelines. Respiratory parameters significantly related to sarcopenia were identified using binomial logistic regression and receiver operating characteristic analyses.

RESULTS

Seventy-seven participants were classified as having sarcopenia. Binomial logistic regression analysis showed that MEP was the only respiratory parameter significantly associated with sarcopenia. The cut-off MEP value for predicting sarcopenia was 47.0 cmH₂0 for men and 40.9 cmH₂0 for women.

CONCLUSIONS

The most appropriate parameter for assessing respiratory sarcopenia may be MEP, which is an indicator of expiratory muscle strength, rather than FVC, MIP, or PEFR, as suggested in previous studies. Measuring MEP is simpler than measuring respiratory function parameters. Moreover, it is expected to have clinical applications such as respiratory sarcopenia screening.

Does Regular Physical Activity Mitigate the Age-Associated Decline in Pulmonary Function?

Whereas the negative effects of aging and smoking on pulmonary function are undisputed, the potential favorable effects of physical activity on the aging process of the otherwise healthy lung remain controversial. This question is of particular clinical relevance when reduced pulmonary function compromises aerobic exercise capacity (maximal oxygen consumption) and thus contributes to an increased risk of morbidity and mortality. Here, we discuss whether and when the aging-related decline in pulmonary function limits maximal oxygen consumption and whether, how, and to what extent regular physical activity can slow down this aging process and preserve pulmonary function and maximal oxygen consumption. Age-dependent effects of reduced pulmonary function (i.e., FEV₁, the volume that has been exhaled after the first second of forced expiration) on maximal oxygen consumption have been observed in several cross-sectional and longitudinal studies. Complex interactions between aging-related cellular and molecular processes affecting the lung, and structural and functional deterioration of the cardiovascular and respiratory systems account for the concomitant decline in pulmonary function and maximal oxygen consumption. Consequently, if long-term regular physical activity mitigates some of the aging-related decline in pulmonary function (i.e., FEV₁ decline), this could also prevent a steep fall in maximal oxygen consumption. In contrast to earlier research findings, recent large-scale longitudinal studies provide growing evidence for the beneficial effects of physical activity on FEV₁. Although further confirmation of those effects is required, these findings provide powerful arguments to start and/or maintain regular physical activity.

Distribuição padrão e percentuais dos valores de pressão respiratória máxima de crianças saudáveis de 7 a 10 anos de idade

Resumo Objetivo: Apresentar distribuição normal para os valores das pressões respiratórias máximas de escolares saudáveis, de acordo com o gênero. Métodos: Estudo transversal envolvendo crianças saudáveis de 7 a 10 anos. Foram avaliados os dados de massa corporal e estatura, para o cálculo do índice de massa corporal (IMC). Os valores de volume expiratório forçado no primeiro segundo (VEF1) e pressão expiratória máxima foram avaliados de acordo com a American Thoracic Society. Os dados de pressão inspiratória máxima (PImáx) e pressão expiratória máxima (PEmáx) obtidos no estudo deram origem à distribuição normal, cuja construção foi elaborada pelo método the Lambda-Mu-Sigma (LMS), bem como os percentis 3, 10, 25, 50, 75, 90 e 97 de PImáx e PImáx de cada sexo. Resultados: Os dados de PImáx e PImáx foram coletados de 399 escolares. Todos os escolares da amostra apresentavam VEF1 e índice de massa corporal adequados. O estudo mostrou aumento dos valores de pressão respiratória com o avançar da idade. Os valores de PImáx e PImáx das meninas foram de 53,49±11,07 e 61,80±12,51cmH2O, respectivamente; e os meninos de 59,96±13,66 e 69,68±15,72 cmH2O, respectivamente. Conclusões: Foram desenvolvidas curvas e percentis normais para os valores de PImáx e PImáx de escolares saudáveis o que poderia auxiliar no acompanhamento clínico e terapêutico de diferentes populações pediátricas.

Standard reference and percentiles of maximum respiratory pressures values of healthy children aged 7–10 years

Objective:

This study aims to present standard reference for values of maximum respiratory pressures of healthy schoolchildren, according to gender.

Methods:

This is a cross-sectional study involving healthy children aged 7–10 years. Data of body mass and height were evaluated to calculate body mass index (BMI). In addition, forced expiratory volume in 1 second (FEV₁) and maximal expiratory pressure values were evaluated according to the American Thoracic Society. The maximal inspiratory pressure (MIP) and data of maximal expiratory pressure (MEP) obtained in the study showed normal distribution and curves were built by the Lambda–Mu–Sigma (LMS) method, as well as the values of MIP and MEP percentiles 3, 10, 25, 50, 75, 90, and 97 for each gender.

Results:

MIP and MEP data were collected from 399 schoolchildren. All schoolchildren in the sample had adequate FEV₁ and BMI. The study showed an increase in respiratory pressure values with age progression. The MIP and MEP values of girls were of 53.4±11.0 and 61.8±12.5cmH₂O, respectively, and those of boys were 59.9±13.6 and 69.6±15.7cmH₂O, respectively.

Conclusions:

Normal curves and percentiles were developed for MIP and MEP values of healthy schoolchildren. The extreme percentiles (3rd and 97th) were determined, and a specific graph was elaborated for each group. These graphs may help clinical follow-up and therapeutic monitoring of different pediatric populations.

Maximal Respiratory Pressures and Maximum Voluntary Ventilation in Young Arabs: Association with Anthropometrics and Physical Activity

Background

Maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP) and maximum voluntary ventilation (MVV) measurements assist in determining the respiratory muscle strength and endurance. These determinants of respiratory muscles vary significantly by age, gender, height, and ethnic origin. Normative values for maximum respiratory pressures (MRPs) and MVV would aid in evaluating respiratory muscle function in athletes, estimating performance, and assisting in rehabilitation. In addition, the reference values may aid in determining the efficacy of therapeutic interventions in young people with chronic respiratory diseases. The purpose of this study was to see how respiratory muscle strength indices correlated with anthropometric and physical activity characteristics in young Arabs.

Methodology

The study included 80 male volunteers and 85 female volunteers ranging in age from 18 to 30 years. MicroRPM was used to measure MIP and MEP, and pulmonary function test data, including MVV values, were recorded. All subjects completed the Global Physical Activity Questionnaire (GPAQ) and anthropometric measurements. Unpaired t-tests or Mann–Whitney U-tests were used to determine male-female differences. Using the Pearson correlation coefficient and Spearman Rho correlation coefficient tests, MIP and MEP values were correlated with body composition and physical activity. Using stepwise multiple linear regression analysis, the relationships between respiratory function (MVV, MIP, and MEP) and PFT values (FVC, FEV1, and FEV1/FVC), physical activity, and sedentary behavior were investigated.

Results

MIP, MEP, and MVV values were significantly lower in females than in males. MIP, MEP, and MVV values had a moderate correlation with forced vital capacity, forced expiratory volume in 1 second, and height, but not with weight, BMI, or GPAQ. Age, gender, and body mass index were found to be significant predictors of maximal respiratory pressures in a young Arab population.

Conclusion

Maximum respiratory pressures and maximal voluntary ventilation were significantly lower in young Arabs than in other ethnic groups; these values were influenced by gender and height but not by levels of physical activity.

Coordination of Respiration, Swallowing, and Chewing in Healthy Young Adults

Examining the coordination of respiration and swallowing is important for elucidating the mechanisms underlying these functions and assessing how respiration is linked to swallowing impairment in dysphagic patients. In this study, we assessed the coordination of respiration and swallowing to clarify how voluntary swallowing is coordinated with respiration and how mastication modulates the coordination of respiration and swallowing in healthy humans. Twenty-one healthy volunteers participated in three experiments. The participants were asked to swallow 3 ml of water with or without a cue, to drink 100 ml of water using a cup without breathing between swallows, and to eat a 4-g portion of corned beef. The major coordination pattern of respiration and swallowing was expiration–swallow–expiration (EE type) while swallowing 3 ml of water either with or without a cue, swallowing 100 ml of water, and chewing. Although cueing did not affect swallowing movements, the expiratory time was lengthened with the cue. During 100-ml water swallowing, the respiratory cycle time and expiratory time immediately before swallowing were significantly shorter compared with during and after swallowing, whereas the inspiratory time did not differ throughout the recording period. During chewing, the respiratory cycle time was decreased in a time-dependent manner, probably because of metabolic demand. The coordination of the two functions is maintained not only in voluntary swallowing but also in involuntary swallowing during chewing. Understanding the mechanisms underlying respiration and swallowing is important for evaluating how coordination affects physiological swallowing in dysphagic patients.

Peak Inspiratory Flow Rate in COPD: An Analysis of Clinical Trial and Real-World Data

Background

The influence of peak inspiratory flow (PIF) on dose delivery from dry powder inhalers (DPIs) and association with treatment efficacy in patients with chronic obstructive pulmonary disease (COPD) has not been fully determined. In vitro studies have demonstrated adequate dose delivery through ELLIPTA DPI at PIF ≥30 L/min. This analysis of two clinical trials and a real-world population of COPD patients determined spirometric PIF distribution, and explored the relationship between PIF and outcomes in the trials.

Methods

The replicate Phase IV, 12-week, randomized, double-blind 207608/207609 (NCT03478683/NCT03478696) trials evaluated fluticasone furoate/umeclidinium/vilanterol via ELLIPTA DPI versus budesonide/formoterol+tiotropium in COPD patients. This post hoc analysis assessed spirometric PIF distribution at screening and relationship between PIF and lung function outcomes in the pooled 207608/207609 population. Spirometric PIF distributions in a real-world population of COPD patients were evaluated by retrospective analysis of the Kaiser Permanente Northwest (KPNW) database to assess similarities between clinical trial and real-world populations.

Results

A total of 1460 (207608/207609) and 3282 (KPNW) patients were included. There was considerable overlap between spirometric PIF distributions for both populations. Overall, 99.7% and 99.8% of the 207608/207609 and KPNW populations, respectively, reported spirometric PIF ≥50 L/min, estimated as equivalent to ELLIPTA PIFR ≥30 L/min. In the 207608/207609 combined analysis, there was no significant interaction between spirometric PIF and treatment for lung function endpoints, indicating treatment effect is independent of PIF.

Conclusion

Nearly all COPD patients in the 207608/207609 and KPNW populations achieved spirometric PIF values estimated as equivalent to PIFR of ≥30 L/min through the ELLIPTA DPI. Lack of correlation between spirometric PIF at screening and treatment efficacy aligns with consistent dose performance from the ELLIPTA DPI across a wide range of PIFs, achieved by patients with COPD of all severities.

Age and sex differences in blood pressure responses during hyperpnoea

NEW FINDINGS

What is the central question of this study? Increased respiratory muscle activation is associated with neural and cardiovascular consequences via the respiratory muscle-induced metaboreflex. Does ageing and/or sex influence the arterial blood pressure response during voluntary normocapnic incremental hyperpnoea? What is the main finding and its importance? The increase in blood pressure during hyperpnoea was smaller in younger females than in older females, whereas no difference was found between older males and older females. The blunted respiratory muscle-induced metaboreflex in younger females is normalized with advancing age, whereas ageing has no such effect in males.

ABSTRACT

We hypothesized that older females (OF) have a greater arterial blood pressure response to increased respiratory muscle work compared with younger females (YF) and that no such difference exists between older males (OM) and younger males (YM). To test these hypotheses, cardiovascular responses during voluntary normocapnic incremental hyperpnoea were evaluated and compared between older and younger subjects. An incremental respiratory endurance test (IRET) was performed as follows: target minute ventilation was initially set at 30% of the maximal voluntary ventilation (MVV12) and was increased by 10% of MVV12 every 3 min. The test was terminated when the subject could not maintain the target percentage of MVV12. Heart rate and mean arterial blood pressure (MAP) were recorded continuously. The increase in MAP from baseline (ΔMAP) during the IRET in OM (+24.0 ± 14.7 mmHg, mean ± SD) did not differ (P = 0.144) from that in YM (+24.3 ± 13.4 mmHg), but it was greater (P = 0.004) in OF (+31.2 ± 11.6 mmHg) than in YF (+10.3 ± 5.5 mmHg). No significant difference in ΔMAP during the IRET was observed between OM and OF (P = 0.975). These results suggest that the respiratory muscle-induced metaboreflex is blunted in YF, but it could be normalized with advancing age. In males, ageing has little effect on the respiratory muscle-induced metaboreflex. These results show no sex difference in the respiratory muscle-induced metaboreflex in older adults.

Respiratory Sarcopenia and Sarcopenic Respiratory Disability: Concepts, Diagnosis, and Treatment

The condition of muscle fiber atrophy and weakness that occurs in respiratory muscles along with systemic skeletal muscle with age is known as respiratory sarcopenia. The Japanese Working Group of Respiratory Sarcopenia of the Japanese Association of Rehabilitation Nutrition narratively reviews these areas, and proposes the concept and diagnostic criteria. We have defined respiratory sarcopenia as "whole-body sarcopenia and low respiratory muscle mass followed by low respiratory muscle strength and/or low respiratory function." Respiratory sarcopenia can be caused by various factors such as aging, decreased activity, undernutrition, disease, cachexia, and iatrogenic causes. We have also created an algorithm for diagnosing respiratory sarcopenia. Respiratory function decreases with age in healthy older people, along with low respiratory muscle mass and strength. We have created a new term, "Presbypnea," meaning a decline in respiratory function with aging. Minor functional respiratory disability due to aging, such as that indicated by a modified Medical Research Council level 1 (troubled by shortness of breath when hurrying or walking straight up hill), is an indicator of presbypnea. We also define sarcopenic respiratory disability as "a disability with deteriorated respiratory function that results from respiratory sarcopenia." Sarcopenic respiratory disability is diagnosed if respiratory sarcopenia is present with functional disability. Cases of respiratory sarcopenia without functional disability are diagnosed as "at risk of sarcopenic respiratory disability." Functional disability is defined as a modified Medical Research Council grade of 2 or more. Rehabilitation nutrition, treatment that combines rehabilitation and nutritional management, may be adequate to prevent and treat respiratory sarcopenia and sarcopenic respiratory disability.

Difference in electromyographic activity between the trapezius muscle and other neck accessory muscles under an increase in inspiratory resistive loading in the supine position

The activity of the trapezius muscle is reportedly higher than that of other neck accessory muscles under a condition of increased inspiratory pressure in the standing position. The present study aimed to compare the activity of the trapezius muscle with those of the scalene and sternocleidomastoid muscles under a condition of increased inspiratory pressure in the supine position. This study included 40 subjects, and the muscle activity was measured using surface electromyography. Regarding the results, there was a significant difference in the muscle activity between the trapezius muscle and the scalene and sternocleidomastoid muscles (p = 0.003) in both men and women. Post-hoc analysis showed significant differences between trapezius and the other muscles. Moreover, there was no difference between the scalene and sternocleidomastoid muscles (p = 0.596). The increase in the change in electromyography activity of the muscle is greater in the trapezius muscle than in other muscles when the level of inspiratory pressure increases in the supine position.

Pearls and Pitfalls in the Crashing Geriatric Patient

The geriatric population is growing and is the largest utilizer of emergency and critical care services; the emergency clinician should be comfortable in the management of the acutely ill geriatric patient. There are important physiologic changes in geriatric patients, which alters their clinical presentation and management. Age alone should not determine the prognosis for elderly patients. Premorbid functional status, frailty, and severity of illness should be considered carefully for the geriatric population. Emergency clinicians should have honest conversations about goals of care based not only a patient's clinical presentation but also the patient's values.

Respiratory Muscle Training Improves Functional Outcomes and Reduces Fatigue in Patients with Myasthenia Gravis: A Single-Center Hospital-Based Prospective Study

Background

Myasthenia gravis (MG) is an immune-mediated disorder characterized by muscle fatigue and fluctuating weakness. Impairment in respiratory strength and endurance has been described in patients with generalized MG. We tested the hypothesis that respiratory muscle training (RMT) can improve functional outcomes and reduce fatigue in patients with MG.

Methods

Eighteen patients with mild to moderate MG participated in this study. The training group underwent home-based RMT three times a week for 12 weeks. Sixteen patients with MG without RMT were enrolled as a disease control group. Lung function, autonomic testing, Multidimensional Fatigue Symptom Inventory-Short Form (MFSI-SF), and functional outcome measurement by using quantitative myasthenia gravis (QMG) score and myasthenia gravis composite (MGC) scale were measured before and after the 12-week RMT.

Results

The 12-week RMT significantly increased forced vital capacity (FVC) from 77.9 ± 12.6% to 83.8 ± 17.7% (p = 0.03), forced expiratory volume in one second (FEV1) from 75.2 ± 18.3% to 83.3 ± 19.0% (p = 0.03), forced expiratory volume in one second (FEV1) from 75.2 ± 18.3% to 83.3 ± 19.0% (p = 0.03), forced expiratory volume in one second (FEV1) from 75.2 ± 18.3% to 83.3 ± 19.0% (p = 0.03), forced expiratory volume in one second (FEV1) from 75.2 ± 18.3% to 83.3 ± 19.0% (p = 0.03), forced expiratory volume in one second (FEV1) from 75.2 ± 18.3% to 83.3 ± 19.0% (p = 0.03), forced expiratory volume in one second (FEV1) from 75.2 ± 18.3% to 83.3 ± 19.0% (

Conclusion

The home-based RMT is an effective pulmonary function training for MG patients. The RMT can not only improve short-term outcomes but also reduce fatigue in patients with mild to moderate generalized MG.

Thoracic gas compression during forced expiration is greater in men than women

Intrapleural pressure during a forced vital capacity (VC) maneuver is often in excess of that required to generate maximal expiratory airflow. This excess pressure compresses alveolar gas (i.e., thoracic gas compression [TGC]), resulting in underestimated forced expiratory flows (FEFs) at a given lung volume. It is unknown if TGC is influenced by sex; however, because men have larger lungs and stronger respiratory muscles, we hypothesized that men would have greater TGC. We examined TGC across the "effort-dependent" region of VC in healthy young men (n = 11) and women (n = 12). Subjects performed VC maneuvers at varying efforts while airflow, volume, and esophageal pressure (POES ) were measured. Quasistatic expiratory deflation curves were used to obtain lung recoil (PLUNG ) and alveolar pressures (i.e., PALV  = POES -PLUNG ). The raw maximal expiratory flow-volume (MEFVraw ) curve was obtained from the "maximum effort" VC maneuver. The TGC-corrected curve was obtained by constructing a "maximal perimeter" curve from all VC efforts (MEFVcorr ). TGC was examined via differences between curves in FEFs (∆FEF), area under the expiratory curves (∆AEX ), and estimated compressed gas volume (∆VGC) across the VC range. Men displayed greater total ∆AEX (5.4 ± 2.0 vs. 2.0 ± 1.5 L2 ·s-1 ; p < .001). ∆FEF was greater in men at 25% of exhaled volume only (p < .05), whereas ∆VGC was systematically greater in men across the entire VC (main effect; p < .05). PALV was also greater in men throughout forced expiration (p < .01). Taken together, these findings demonstrate that men display more TGC, occurring early in forced expiration, likely due to greater expiratory pressures throughout the forced VC maneuver.

Peak Expiratory Flow and the Risk of Injurious Falls in Older Adults: The Role of Physical and Cognitive Deficits

OBJECTIVES

Previous studies showed that peak expiratory flow (PEF) is associated with health-related outcomes in advanced age, but the extent to which it may be related to falls risk remains unclear. We aimed to detect the association between PEF and injurious falls in older adults and to explore the role of cognitive and physical deficits in this association.

DESIGN

Prospective study with a 6-year follow-up.

SETTING AND PARTICIPANTS

The study involves 2234 community-dwelling older adults with no history of pulmonary disease.

METHODS

For each study participant, we assessed the PEF at baseline, expressed as standardized residual (SR) percentile and derived from the normalization of residuals between the measured and predicted PEF values (based on individual age, sex, and body height); incident injurious falls over 6 years, from Hospital Discharge Diagnosis; and physical and cognitive functioning at the baseline and at 3- and 6-year follow-ups by evaluating walking speed, balance, chair stand, and Mini-Mental State Examination, respectively.

RESULTS

Over the follow-up, 232 individuals experienced injurious falls. Cox models indicated 7% higher risk of falls per each 10th reduction in PEF SR-percentile. The risk of injurious falls increased by more than twice for those who had PEF SR-percentile <10th as for values of 80th-100th (hazard ratio = 2.31, 95% confidence interval: 1.41-3.76). Physical deficits mediated 63% of the total effect of PEF on falls risk.

CONCLUSIONS AND IMPLICATIONS

Our findings suggest that low PEF is associated with higher risk of injurious falls in older adults, and most of this association is explained by balance or muscular strength deficits.

The Confusing World of Dry Powder Inhalers: It Is All About Inspiratory Pressures, Not Inspiratory Flow Rates

Dry powder inhalers (DPIs) all have the ability to aerosolize dry powders, but they each offer different operating mechanisms and resistances to inhaled airflow. This variety has resulted in both clinician and patient confusion concerning DPI performance, use, and effectiveness. Particularly, there is a growing misconception that a single peak inspiratory flow rate (PIFR) can determine a patient's ability to use a DPI effectively, regardless of its design or airflow resistance. For this review article, we have sifted through the relevant literature concerning DPIs, inspiratory pressures, and inspiratory flow rates to provide a comprehensive and concise discussion and recommendations for DPI use. We ultimately clarify that the controlling parameter for DPI performance is not the PIFR but the negative pressure generated by the patient's inspiratory effort. A pressure drop ∼≥1 kPa (∼10 cm H₂O) with any DPI is a reasonable threshold above which a patient should receive an adequate lung dose. Overall, we explore the underlying factors controlling inspiratory pressures, flow rates and dispensing, and dispersion characteristics of the various DPIs to clarify that inspiratory pressures, not flow rates, limit and control a patient's ability to generate sufficient flow for effective DPI use.

Muscle Evaluation in Axial Spondyloarthritis-The Evidence for Sarcopenia

Sarcopenia is a syndrome defined as a progressive and generalized skeletal muscle disorder associated with an increased likelihood of adverse outcomes such as falls, fractures, physical disability, and death. The actual definition of sarcopenia is based on a reduction in the values of three parameters: strength, muscle mass quantity or quality, and physical performance (the determinant of severity). Muscle wasting is a common feature in several chronic diseases, such as spondyloarthritis (SpA), and significantly increases patient morbidity and mortality. Although there has been huge progress in this field over recent years, the absence of a clear definition and clear diagnostic criteria of sarcopenia has resulted in inconsistent information regarding muscle-involvement in SpA. Thus, the aim of this review is to collect relevant evidence on muscular changes occurring during the disease process from the published literature, according to the recommended tools for sarcopenia evaluation proposed by the European Working Group on Sarcopenia in Older People 2 (EWGSOP2). In addition, data from histological, electromyography, and biochemical muscle analyses of SpA patients are also reviewed. Overall, a reduction in muscle strength with a systemic decrease in lean mass seems to be associated with a gait speed compromise. This information is usually fragmented, with no studies considering the three parameters together. This paper represents a call-to-action for the design of new studies in the future.

A Super-Learner Model for Tumor Motion Prediction and Management in Radiation Therapy: Development and Feasibility Evaluation

In cancer radiation therapy, large tumor motion due to respiration can lead to uncertainties in tumor target delineation and treatment delivery, thus making active motion management an essential step in thoracic and abdominal tumor treatment. In current practice, patients with tumor motion may be required to receive two sets of CT scans – the initial free-breathing 4-dimensional CT (4DCT) scan for tumor motion estimation and a second CT scan under appropriate motion management such as breath-hold or abdominal compression. The aim of this study is to assess the feasibility of a predictive model for tumor motion estimation in three-dimensional space based on machine learning algorithms. The model was developed based on sixteen imaging features extracted from non-4D diagnostic CT images and eleven clinical features extracted from the Electronic Health Record (EHR) database of 150 patients to characterize the lung tumor motion. A super-learner model was trained to combine four base machine learning models including the Random Forest, Multi-Layer Perceptron, LightGBM and XGBoost, the hyper-parameters of which were also optimized to obtain the best performance. The outputs of the super-learner model consist of tumor motion predictions in the Superior-Inferior (SI), Anterior-Posterior (AP) and Left-Right (LR) directions, and were compared against tumor motions measured in the free-breathing 4DCT scans. The accuracy of predictions was evaluated using Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) through ten rounds of independent tests. The MAE and RMSE of predictions in the SI direction were 1.23 mm and 1.70 mm; the MAE and RMSE of predictions in the AP direction were 0.81 mm and 1.19 mm, and the MAE and RMSE of predictions in the LR direction were 0.70 mm and 0.95 mm. In addition, the relative feature importance analysis demonstrated that the imaging features are of great importance in the tumor motion prediction compared to the clinical features. Our findings indicate that a super-learner model can accurately predict tumor motion ranges as measured in the 4DCT, and could provide a machine learning framework to assist radiation oncologists in determining the active motion management strategy for patients with large tumor motion.

Towards real-time respiratory motion prediction based on long short-term memory neural networks

Radiation therapy of thoracic and abdominal tumors requires incorporating the respiratory motion into treatments. To precisely account for the patient's respiratory motions and predict the respiratory signals, a generalized model for predictions of different types of patients' respiratory motions is desired. The aim of this study is to explore the feasibility of developing a long short-term memory (LSTM)-based generalized model for the respiratory signal prediction. To achieve that, 1703 sets of real-time position management (RPM) data were collected from retrospective studies across three clinical institutions. These datasets were separated as the training, internal validity and external validity groups. Among all the datasets, 1187 datasets were used for model development and the remaining 516 datasets were used to test the model's generality power. Furthermore, an exhaustive grid search was implemented to find the optimal hyper-parameters of the LSTM model. The hyper-parameters are the number of LSTM layers, the number of hidden units, the optimizer, the learning rate, the number of epochs, and the length of time lags. The obtained model achieved superior accuracy over conventional artificial neural network (ANN) models: with the prediction window equaling to 500 ms, the LSTM model achieved an average relative mean absolute error (MAE) of 0.037, an average root mean square error (RMSE) of 0.048, and a maximum error (ME) of 1.687 in the internal validity data, and an average relative MAE of 0.112, an average RMSE of 0.139 and an ME of 1.811 in the external validity data. Compared to the LSTM model trained with default hyper-parameters, the MAE of the optimized model results decreased by 20%, indicating the importance of tuning the hyper-parameters of LSTM models to obtain superior accuracies. This study demonstrates the potential of deep LSTM models for the respiratory signal prediction and illustrates the impacts of major hyper-parameters in LSTM models.

Estimation of Breathing Rate with Confidence Interval Using Single-Channel CW Radar

Breathing rate monitoring using continuous wave (CW) radar has gained much attention due to its contact-less nature and privacy-friendly characteristic. In this work, using a single-channel CW radar, a breathing rate estimation method is proposed that deals with system nonlinearity of a single-channel CW radar and realizes a reliable breathing rate estimate by including confidence intervals. To this end, time-varying dominant Doppler frequency of radar signal, in the range of breathing rate, is extracted in time-frequency domain. It is shown through simulation and mathematical modeling that the average of the dominant Doppler frequencies over time provides an estimation of breathing rate. However, this frequency is affected by noise components and random body movements over time. To address this issue, the sum of these unwanted components is extracted in time-frequency domain, and from their surrogate versions, bootstrap resamples of the measured signal are obtained. Accordingly, a 95% confidence interval is calculated for breathing rate estimation using the bootstrap approach. The proposed method is validated in three different postures including lying down, sitting, and standing, with or without random body movements. The results show that using the proposed algorithm, estimation of breathing rate is feasible using single-channel CW radar. It is also shown that even in presence of random body movements, average of absolute error of estimation for all three postures is 1.88 breath per minute, which represents 66% improvement as compared to the Fourier transform-based approach.

Association between respiratory capacity, quality of life and cognitive function in elderly individuals

OBJECTIVE

To investigate associations between respiratory capacity, quality of life and cognitive function in elderly individuals.

METHODS

The sample included 386 elderly individuals (232 women). Respiratory capacity assessment was based on maximal expiratory pressure measured at peak expiratory flow. Subjects were classified according to peak expiratory flow values adjusted for sex, age and height of individuals with normal (peak expiratory flow curve <80% and >60%) or reduced (peak expiratory flow curve < 60%) respiratory capacity. The World Health Organization Quality of Life Questionnaire and the Mini-Mental State Examination were used to assess quality of life and cognitive function, respectively.

RESULTS

Elderly women with reduced respiratory capacity scored lower on the Mini-Mental State Examination (p=0.048) and quality of life questionnaire (p=0.040) compared to those with normal respiratory capacity. These differences were not observed in men (p>0.05).

CONCLUSION

Reduced respiratory capacity was associated with poorer quality of life and cognitive function in elderly women. These associations were not observed in elderly men.

Predictive equations for respiratory muscle strength by anthropometric variables

Recent studies have pointed out divergences in the predictive quality of reference equations for respiratory muscle strength, alerting the need to introduce into these equation-specific variables for certain target populations.

OBJECTIVES

This study proposes predictive equations of respiratory muscle strength by the variables such as body weight and body mass index (BMI = weight/height² ).

MATERIALS AND METHODS

This is a cross-sectional study, and the evaluation was made by the test of maximum static respiratory pressures (MIP and MEP) according to standard protocol of the Brazilian Society of Pneumology and Tisiology. For data analysis, the following three models of linear regression were adjusted: age, age/weight, age/BMI. The software used in the analysis was the R version 3.2.1.

RESULTS

Of the 353 subjects evaluated (229 women and 124 men), 109 subjects were normal weight, 101 subjects were overweight and 143 subjects were obese. The BMI average of the individuals was 31.42 ± 10.26 kg/m² and age 46.26 ± 16.47 years. The two statistical models that considered the variables weight and BMI had the R² value of 29.86% for MEP and 21.77% for MIP when the weight was the predictive variable and 21.33% for MIP and 28.38% for MEP when the variable was BMI.

CONCLUSION

It was found with the adjusted models that there was a considerable gain in the predictive quality of the models for MEP and MIP adding weight or BMI, without significant difference between both.

Diaphragmatic Ultrasound Correlates with Inspiratory Muscle Strength and Pulmonary Function in Healthy Subjects

Diaphragm ultrasound (DUS) has been used to identify diaphragm dysfunction. However, its correlations with respiratory strength and lung function are unclear, even in healthy patients. A total of 64 healthy patients (30 males) had lung function and inspiratory strength (maximal inspiratory pressure and sniff nasal inspiratory pressure) measured. Gastric and oesophageal pressures were measured in a subgroup (n = 40). DUS was characterized by mobility (quiet breathing [QB] and deep breathing [DB]) and thickness (at functional residual capacity [Th_FRC] and total lung capacity [Th_TLC]). We calculated the thickening fraction (TF). During QB, DUS was similar between sexes. However, during DB, females had lower mobility, thickness and TF than males. Mobility at DB, Th_TLC and TF significantly correlated with lung function and inspiratory strength. These correlations were affected by sex. DUS correlated with inspiratory gastric pressure. In healthy patients, DUS correlated with lung function and inspiratory strength during DB. Significant differences between genders were noticeable when DUS was performed during DB.

Relationships among peak expiratory flow rate, body composition, physical function, and sarcopenia in community-dwelling older adults

BACKGROUND AND AIM

Although respiratory muscle strength is known to decrease with age, the relationship between pulmonary function and sarcopenia remains to be examined. The present study aimed to determine the relationship between peak expiratory flow rate (PEFR) and skeletal muscle mass/sarcopenia in community-dwelling older adults.

METHODS

We utilized data from 427 older adults (age 74.4 ± 5.3 years, men/women 157/270) who had participated in the 2015 Otassha Kenshin, a longitudinal study that excluded participants with air-flow limitations. Diagnoses of sarcopenia were based on criteria outlined in the Consensus Report of the Asian Working Group for Sarcopenia and adjusted for Japanese individuals. We compared body composition, physical function, and lung function between patients with and without sarcopenia. Receiver operating characteristic analysis (ROC) for sarcopenia was performed using PEFR, calf circumference, and body mass index.

RESULTS

Sixty-five participants (men/women 12/53) were diagnosed with sarcopenia. Patients with sarcopenia were older than those without sarcopenia, and had lower height, weight, body mass index, skeletal muscle mass, appendicular skeletal mass, and skeletal muscle index. Stepwise multiple regression analysis identified whole-body skeletal mass as an independent factor for PEFR. ROC analysis of sarcopenia identified a cut-off value of 5.0 L s for PEFR, with a sensitivity of 0.62, specificity of 0.77, and area under the curve of 0.73 (95% CI 0.67-0.79; P < 0.001).

DISCUSSION AND CONCLUSION

Our findings suggest that physical function is more strongly associated with respiratory muscle mass than total skeletal muscle mass and that PEFR may be a valid indicator of sarcopenia.

A Systematic Review of Associations of Physical Activity and Sedentary Time with Asthma Outcomes

BACKGROUND

Physical inactivity and high sedentary time are associated with adverse health outcomes in several diseases. However, their impact in asthma is less clear.

OBJECTIVE

We aimed to synthesize the literature characterizing physical activity and sedentary time in adults with asthma, to estimate activity levels using meta-analysis, and to evaluate associations between physical activity and sedentary time and the clinical and physiological characteristics of asthma.

METHODS

Articles written in English and addressing the measurement of physical activity or sedentary time in adults ≥18 years old with asthma were identified using 4 electronic databases. Meta-analysis was used to estimate steps/day in applicable studies.

RESULTS

There were 42 studies that met the inclusion criteria. Physical activity in asthma was lower compared with controls. The pooled mean (95% confidence interval) steps/day for people with asthma was 8390 (7361, 9419). Physical activity tended to be lower in females compared with males, and in older people with asthma compared with their younger counterparts. Higher levels of physical activity were associated with better measures of lung function, disease control, health status, and health care use. Measures of sedentary time were scarce, and indicated a similar engagement in this behavior between participants with asthma and controls. High sedentary time was associated with higher health care use, and poorer lung function, asthma control, and exercise capacity.

CONCLUSIONS

People with asthma engage in lower levels of physical activity compared with controls. Higher levels of physical activity may positively impact on asthma clinical outcomes. Sedentary time should be more widely assessed.

Daily inspiratory muscle training lowers blood pressure and vascular resistance in healthy men and women

NEW FINDINGS

What is the central question of this study? What impact does inspiratory muscle training have on systemic vascular resistance, cardiac output and baroreflex sensitivity in adult men and women? What is the main finding and its importance? Inspiratory muscle training exerts favorable effects on blood pressure, vascular resistance and perception of stress. This exercise format is well-tolerated and equally effective whether implemented in men or women.

ABSTRACT

Previous work has shown that inspiratory muscle training (IMT) lowers blood pressure after a mere 6 weeks, identifying IMT as a potential therapeutic intervention to prevent or treat hypertension. Here, we explore the effects of IMT on respiratory muscle strength and select cardiovascular parameters in recreationally active men and women. Subjects were randomly assigned to IMT (n = 12, 75% maximal inspiratory pressure) or sham training (n = 13, 15% maximal inspiratory pressure) groups and underwent a 6-week intervention comprising 30 breaths day^-1 , 5 days week^-1 . Pre- and post-training measures included maximal inspiratory pressure and resting measures of blood pressure, cardiac output, heart rate, spontaneous cardiac baroreflex sensitivity and systemic vascular resistance. We evaluated psychological and sleep status via administration of the Cohen-Hoberman inventory of physical symptoms and the Epworth sleepiness scale. Male and female subjects in the IMT group showed declines in systolic/diastolic blood pressures (-4.3/-3.9 mmHg, P < 0.025) and systemic vascular resistance (-3.5 mmHg min l^-1 , P = 0.008) at week 6. There was no effect of IMT on cardiac output (P = 0.722), heart rate (P = 0.795) or spontaneous cardiac baroreflex sensitivity (P = 0.776). The IMT subjects also reported fewer stress-related symptoms (pre- versus post-training, 12.5 ± 8.5 versus 7.2 ± 9.7, P = 0.025). Based on these results, we suggest that a short course of IMT confers significant respiratory and cardiovascular improvements and parallel (modest) psychological benefits in healthy men and women.

Leisure-time vigorous physical activity is associated with better lung function: the prospective ECRHS study

OBJECTIVE

We assessed associations between physical activity and lung function, and its decline, in the prospective population-based European Community Respiratory Health Survey cohort.

METHODS

FEV₁ and FVC were measured in 3912 participants at 27-57 years and 39-67 years (mean time between examinations=11.1 years). Physical activity frequency and duration were assessed using questionnaires and used to identify active individuals (physical activity ≥2 times and ≥1 hour per week) at each examination. Adjusted mixed linear regression models assessed associations of regular physical activity with FEV₁ and FVC.

RESULTS

Physical activity frequency and duration increased over the study period. In adjusted models, active individuals at the first examination had higher FEV₁ (43.6 mL (95% CI 12.0 to 75.1)) and FVC (53.9 mL (95% CI 17.8 to 89.9)) at both examinations than their non-active counterparts. These associations appeared restricted to current smokers. In the whole population, FEV₁ and FVC were higher among those who changed from inactive to active during the follow-up (38.0 mL (95% CI 15.8 to 60.3) and 54.2 mL (95% CI 25.1 to 83.3), respectively) and who were consistently active, compared with those consistently non-active. No associations were found for lung function decline.

CONCLUSION

Leisure-time vigorous physical activity was associated with higher FEV₁ and FVC over a 10-year period among current smokers, but not with FEV₁ and FVC decline.

The Influence of Clinically Diagnosed Neuropathy on Respiratory Muscle Strength in Type 2 Diabetes Mellitus

OBJECTIVES

This cross-sectional study investigated the influence of clinically diagnosed neuropathy (cdNP) on respiratory muscle strength in patients with type 2 diabetes mellitus (T2DM).

METHODS

110 T2DM patients and 35 nondiabetic healthy controls (≥60 years) were allocated to one of three groups depending on the presence of cdNP: T2DM without cdNP (D-; n = 28), T2DM with cdNP (D+; n = 82), and controls without cdNP (C; n = 35). Clinical neurological diagnostic examination consisted of Vibration Perception Threshold and Diabetic Neuropathy Symptom score. Respiratory muscle strength was registered by maximal Inspiratory and Expiratory Pressures (PI_max and PE_max), and respiratory function by Peak Expiratory Flow (PEF). Isometric Handgrip Strength and Short Physical Performance Battery were used to evaluate peripheral skeletal muscle strength and physical performance. Univariate analysis of covariance was used with age, level of physical activity, and body mass index as covariates.

RESULTS

PI_max, PE_max, and PEF were higher in C compared to D- and D+. Exploring more in detail, PI_max, PE_max, and PEF were significantly lower in D+ compared to C. PE_max and PEF were also significantly lower in D- versus C. Measures of peripheral muscle strength and physical performance showed less associations with cdNP and T2DM.

CONCLUSIONS

The presence of cdNP affects respiratory muscle strength in T2DM patients compared to healthy controls. Both cdNP and diabetes in themselves showed a distinctive impact on respiratory muscle strength and function; however, an accumulating effect could not be ascertained in this study. As commonly used measures of peripheral muscle strength and physical performance seemed to be less affected at the given time, the integration of PI_max, PE_max, and PEF measurements in the assessment of respiratory muscle weakness could be of added value in the (early) screening for neuropathy in patients with T2DM.

Voluntary cough intensity and its influencing factors differ by sex in community-dwelling adults

Background:

Cough peak flow (CPF) is widely used for measuring voluntary cough intensity. However, the respective factors that affect CPF are not known. The aim of this study was to determine the factors affecting CPF by sex in community-dwelling adults.

Method:

We recruited participants using posters exhibited at a public gymnasium. Participation was voluntary, and all participants provided informed consent. Nonsmoking community residents (102 males, 49.6 ± 20.2 years of age; 101 females, 51.4 ± 18.4 years of age) participated in this study. The main outcome measures were sex differences in CPF, respiratory function, respiratory muscle strength, thorax extension, and grip strength. Factors affecting CPF by sex were analyzed using multiple regression analysis.

Results:

All parameters were higher in men than in women. CPF was affected by thorax expansion at the tenth rib, inspiratory muscle strength and forced expiration in 1 s in men, and thorax expansion at the tenth rib, inspiratory reserve volume, and expiratory muscle power in women. A weak negative correlation was observed between CPF and age (p = −0.24, p < 0.05) in women.

Conclusions:

The factors affecting CPF differed by sex in community-dwelling adults.

Clinical Trial Number: UMIN000023912

Osteosarcopenia: where bone, muscle, and fat collide

As the world's population ages, the prevalence of chronic diseases increases. Sarcopenia and osteoporosis are two conditions that are associated with aging, with similar risk factors that include genetics, endocrine function, and mechanical factors. Additionally, bone and muscle closely interact with each other not only anatomically, but also chemically and metabolically. Fat infiltration, a phenomenon observed in age-related bone and muscle loss, is highly prevalent and more severe in sarcopenic and osteoporotic subjects. Clinically, when individuals suffer a combination of both disorders, negative outcomes such as falls, fractures, loss of function, frailty, and mortality increase, thus generating significant personal and socio-economic costs. Therefore, it is suggested that when bone mineral density loss is synchronic with decreased muscle mass, strength, and function, it should be interpreted as a single diagnosis of osteosarcopenia, which may be preventable and treatable. Simple interventions such as resistance training, adequate protein and calcium dietary intake, associated with maintenance of appropriate levels of vitamin D, have a dual positive effect on bone and muscle, reducing falls, fractures, and, consequently, disability. It is essential that fracture prevention approaches-including postfracture management-involve assessment and treatment of both osteoporosis and sarcopenia. This is of particular importance as in older persons the combination of osteopenia/osteoporosis and sarcopenia has been proposed as a subset of frailer individuals at higher risk of institutionalization, falls, and fractures. This review summarizes osteosarcopenia epidemiology, pathophysiology, diagnosis, outcomes, and management strategies.

Cardiovascular consequences of the inspiratory muscle metaboreflex: effects of age and sex

With inspiratory muscle metaboreflex activation, we hypothesized that, compared with their younger counterparts, older men and women would exhibit greater 1) increases in mean arterial pressure (MAP) and limb vascular resistance (LVR) and 2) decreases in limb blood flow (Q̇L) but 3) no sex differences would be present in older adults. Sixteen young adults [8 young men (YM) and 8 young women (YW), 18–24 yr] and 16 older adults [8 older men (OM) and 8 older women (OW), 60–73 yr] performed inspiratory resistive breathing tasks (IRBTs) at 2% and 65% of their maximal inspiratory pressure. During the IRBTs, breathing frequency was 20 breaths/min with a 50% duty cycle. At baseline and during the IRBTs, MAP was measured via automated oscillometry, Q̇L was determined via Doppler ultrasound, and LVR was calculated. The 65% IRBT led to significantly greater increases in MAP in OW (15.9 ± 8.1 mmHg) compared with YW (6.9 ± 1.4 mmHg) but not ( P > 0.05) between OM (12.3 ± 5.7 mmHg) and YM (10.8 ± 5.7 mmHg). OW (−20.2 ± 7.2%) had greater ( P < 0.05) decreases in Q̇L compared with YW (−9.4 ± 10.2%), but no significant differences were present between OM (−22.8 ± 9.7%) and YM (−22.7 ± 11.3%) during the 65% IRBT. The 65% IRBT led to greater ( P < 0.05) increases in LVR in OW (48.2 ± 25.5%) compared with YW (19.7 ± 15.0%), but no differences ( P > 0.05) existed among OM (54.4 ± 17.8%) and YM (47.1 ± 23.3%). No significant differences were present in MAP, Q̇L, or LVR between OM and OW. These data suggest that OW exhibit a greater inspiratory muscle metaboreflex compared with YW, whereas no differences between OM and YM existed. Finally, sex differences in the inspiratory muscle metaboreflex are not present in older adults.

NEW & NOTEWORTHY Premenopausal women exhibit an attenuated inspiratory muscle metaboreflex compared with young men; however, it is unknown whether these sex differences are present in older adults. Older women exhibited a greater inspiratory muscle metaboreflex compared with premenopausal women, whereas no differences were present between older and younger men.

Comparison of abdominal muscle activity and peak expiratory flow between forced vital capacity and fast expiration exercise

[Purpose] The purpose of this investigation was to compare the activities of the abdominal muscles and peak expiratory flow between forced vital capacity and fast expiration exercise. [Subjects and Methods] Fifteen healthy male participated in this study. Peak expiratory flow and electromyographic activities of the rectus abdominis, external oblique, and internal oblique/transversus abdominis muscles were measured during forced vital capacity and fast expiration exercise and then peak amplitude and its appearance time were obtained. [Results] Peak expiratory flow values were significantly higher during fast expiration exercise than during forced vital capacity. The internal oblique/transversus abdominis muscles showed significantly higher peak amplitude during fast expiration exercise than during forced vital capacity. However, there were no significant differences between forced vital capacity and fast expiration exercise in the rectus abdominis and external oblique muscles. There was no difference in the appearance time of the peak amplitude between forced vital capacity and fast expiration exercise in any muscle. [Conclusion] Fast expiration exercise might be beneficial for increasing expiratory speed and neuromuscular activation of the internal oblique/transversus abdominis muscles compared to forced vital capacity. These findings could be considered when recommending a variation of expiratory muscle strength training as part of pulmonary rehabilitation programs.

Predictive equations for maximal respiratory pressures of children aged 7-10

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Predictive equations allow comparisons between children with or without changes in respiratory muscle strength.

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Predictive equations facilitate the monitoring and control of physical therapy interventions.

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Age and biometric measurements had little influence on the values of maximal respiratory pressures.

Background

Measurements of respiratory muscle strength are widely used for assessment in children; however, clearly defined predictive equations for the Brazilian pediatric population have yet to be established.

Objective

To determine the prediction equations for maximal respiratory pressures in healthy children.

Method

Cross-sectional observational study with normal-weight students aged 7–10 years (n = 399, 198 boys) with health attested by the (International Study of Asthma and Allergies in Childhood) questionnaire and medical history. Biometric data were evaluated (weight, height, and body mass index) as predictors. Spirometry and maximal expiratory pressure values were measured according to the recommendations of the American Thoracic Society. To verify data normality, the Shapiro–Wilk test was applied, and Pearson's test was used to verify the correlation between variables. The models were developed using simple linear regression and multivariate analyses. For all tests, the significance level was p < 0.05.

Results

Boys showed higher values of maximal respiratory pressures than girls, both increasing with age. For boys, these values had moderate correlation with age, weight, and height and weak correlation with body mass index. For girls, maximum inspiratory pressure had a weak correlation with age and moderate correlation with biometric data. Maximum expiratory pressure had a moderate correlation with age and biometric measures. The best predictive models were found in boys: Log(MIP) = 1.577 + 0.006 × weight (kg) (R²_aj = 14.1%) and Log(MEP) = 1.282 + 0.409 × height (m) (R²_aj = 13.9%); and for girls: Log(MIP) = 1.548 + 0.006 × weight (kg) (R²_aj = 15.0%) and Log(MEP) = 1.524 + 0.012 × age (years) + 0.005 × weight (kg) (R²_aj = 21.6%).

Conclusion

Prediction equations for maximal respiratory pressures were developed for boys and girls. The biometric measurements were shown to have a weak influence on the results.

Effect of Sarcopenia on Postoperative Morbidity and Mortality After Thoracolumbar Spine Surgery

Sarcopenia is the loss of muscle mass associated with aging and advanced disease. This study retrospectively examined patients older than 55 years (N=46) who underwent thoracolumbar spine surgery between 2003 and 2015. Each patient's comorbidity burden was determined using the Charlson Comorbidity Index, and the Mirza Surgical Invasiveness Index was used to measure procedural complexity. Sarcopenia was diagnosed by measuring the total cross-sectional area of the psoas muscle at the L4 vertebrae using perioperative computed tomography scans. Of the 46 patients assessed, 16 were in the lowest third for L4 total psoas area (sarcopenic). Average follow-up time was 5.2 years (range, 6 days to 12.7 years). The cohort of patients with sarcopenia was significantly older than the cohort without sarcopenia (mean age, 76.4 vs 69.9 years; P=.01) but did not have a significantly different mean Charlson Comorbidity Index (3.3 vs 2.0; P=.32) or mean Mirza Surgical Invasiveness Index (7.1 vs 7.0; P=.49). Patients with sarcopenia had a hospital length of stay 1.7-fold longer than those without sarcopenia (8.1 vs 4.7 days; P=.02) and a 3-fold increase in postoperative in-hospital complications (1.2 vs 0.4; P=.02), and they were more likely to require discharge to a rehabilitation or nursing facility (81.2% vs 43.3%; P=.006). Patients with sarcopenia had a significantly lower cumulative survival (log rank=0.007). All 4 deaths occurred among patients with sarcopenia. Patients with sarcopenia have a significantly increased risk of in-hospital complications, longer length of stay, increased rates of discharge to rehabilitation facilities, and increased mortality following thoracolumbar spinal surgery, making sarcopenia a useful perioperative risk stratification tool. [Orthopedics. 2016; 39(6):e1159-e1164.].

Respiratory Changes in Response to Cognitive Load: A Systematic Review

When people focus attention or carry out a demanding task, their breathing changes. But which parameters of respiration vary exactly and can respiration reliably be used as an index of cognitive load? These questions are addressed in the present systematic review of empirical studies investigating respiratory behavior in response to cognitive load. Most reviewed studies were restricted to time and volume parameters while less established, yet meaningful parameters such as respiratory variability have rarely been investigated. The available results show that respiratory behavior generally reflects cognitive processing and that distinct parameters differ in sensitivity: While mentally demanding episodes are clearly marked by faster breathing and higher minute ventilation, respiratory amplitude appears to remain rather stable. The present findings further indicate that total variability in respiratory rate is not systematically affected by cognitive load whereas the correlated fraction decreases. In addition, we found that cognitive load may lead to overbreathing as indicated by decreased end-tidal CO₂ but is also accompanied by elevated oxygen consumption and CO₂ release. However, additional research is needed to validate the findings on respiratory variability and gas exchange measures. We conclude by outlining recommendations for future research to increase the current understanding of respiration under cognitive load.

Inspiratory muscle performance in endurance-trained elderly males during incremental exercise

The aim of this study was to compare the inspiratory muscle performance during an incremental exercise of twelve fit old endurance-trained athletes (OT) with that of fit young athletes (YT) and healthy age-matched controls (OC). The tension-time index (TT0.1) was determined according to the equation TT0.1=P0.1/PImax×ti/ttot, where P0.1 is the mouth occlusion pressure, PImax the maximal inspiratory pressure and ti/ttot the duty cycle. For a given VCO2, OT group displayed P0.1, P0.1/PImax ratio, TT0.1 and effective impedance of the respiratory muscle values which were lower than OC group and higher than YT group. At maximal exercise, P0.1/PImax ratio and TT0.1 was still lower in the OT group than OC group and higher than YT group. This study showed lower inspiratory muscle performance attested by a higher (TT0.1) during exercise in the OT group than YT group, but appeared to be less marked in elderly men having performed lifelong endurance training compared with sedentary elderly subjects.

Correlation Between Abdominal Muscle Thickness and Maximal Expiratory Pressure

OBJECTIVES

The activity of abdominal muscles mainly produces high expiratory pressure. These include the rectus abdominis, external oblique, internal oblique, and transverse abdominis muscles. The purpose of this study was to determine whether maximal expiratory pressure is associated with each abdominal muscle thickness at rest.

METHODS

Thirty-nine healthy male volunteers (mean age ± SD, 20.7 ± 2.7 years) participated in the study. The thickness of the right rectus abdominis, external oblique, internal oblique, and transverse abdominis muscles was measured by B-mode sonography in the supine position. The maximal expiratory pressure was obtained with a spirometer in the sitting position. The correlations between each abdominal muscle thickness and maximal expiratory pressure were determined by the Pearson correlation coefficient.

RESULTS

The correlation coefficient between the rectus abdominis muscle and maximal expiratory pressure was 0.571 (P< .001). Correlation coefficients between the external oblique, internal oblique, and transverse abdominis muscles and maximal expiratory pressure were 0.297 (P = .066), 0.267 (P = .100), and 0.022 (P = .894), respectively.

CONCLUSIONS

Our results indicate that the rectus abdominis muscle thickness might be more highly correlated with expiratory pressure production than the external oblique, internal oblique, and transverse abdominis muscle thickness.

Lung function profiles and aerobic capacity of adult cigarette and hookah smokers after 12 weeks intermittent training

INTRODUCTION

Pulmonary function is compromised in most smokers. Yet it is unknown whether exercise training improves pulmonary function and aerobic capacity in cigarette and hookah smokers and whether these smokers respond in a similar way as do non-smokers.

AIM

To evaluate the effects of an interval exercise training program on pulmonary function and aerobic capacity in cigarette and hookah smokers.

METHODS

Twelve cigarette smokers, 10 hookah smokers, and 11 non-smokers participated in our exercise program. All subjects performed 30 min of interval exercise (2 min of work followed by 1 min of rest) three times a week for 12 weeks at an intensity estimated at 70% of the subject's maximum aerobic capacity (VO2max). Pulmonary function was measured using spirometry, and maximum aerobic capacity was assessed by maximal exercise testing on a treadmill before the beginning and at the end of the exercise training program.

RESULTS

As expected, prior to the exercise intervention, the cigarette and hookah smokers had significantly lower pulmonary function than the non-smokers. The 12-week exercise training program did not significantly affect lung function as assessed by spirometry in the non-smoker group. However, it significantly increased both forced expiratory volume in 1 second and peak expiratory flow (PEF) in the cigarette smoker group, and PEF in the hookah smoker group. Our training program had its most notable impact on the cardiopulmonary system of smokers. In the non-smoker and cigarette smoker groups, the training program significantly improved VO2max (4.4 and 4.7%, respectively), v VO2max (6.7 and 5.6%, respectively), and the recovery index (7.9 and 10.5%, respectively).

CONCLUSIONS

After 12 weeks of interval training program, the increase of VO2max and the decrease of recovery index and resting heart rate in the smoking subjects indicated better exercise tolerance. Although the intermittent training program altered pulmonary function only partially, both aerobic capacity and life quality were improved. Intermittent training should be advised in the clinical setting for subjects with adverse health behaviors.

Correlation between Peak Expiratory Flow and Abdominal Muscle Thickness

[Purpose] The purpose of this study was to determine whether forced expiration is correlated with abdominal muscle thickness. [Subjects] Twenty-three healthy male volunteers participated in this study. [Methods] The peak expiratory flow (PEF) was obtained using a peak flow meter with subjects in the sitting position. The thicknesses of the right rectus abdominis, external oblique, internal oblique, and transverse abdominis muscles were measured using B-mode ultrasonography at the end of a relaxed expiration in the supine position. [Results] Among the abdominal muscles, only the thickness of the external oblique muscle displayed a significant correlation with PEF. [Conclusion] It appears that the thickness of the external oblique muscle might be associated with PEF during forced expiration.