Can Daily Walking Alone Reduce Pneumonia-Related Mortality among Older People?

Demystifying roles of exercise in immune response regulation against acute respiratory infections: A narrative review

The benefits of physical activity and exercise, especially those classified as moderate-to-vigorous activity (MVPA), have been well-established in preventing non-communicable diseases and mental health problems in healthy adults. However, the relationship between physical activity and exercise and the prevention and management of acute respiratory infection (ARI), a global high-burden disease, has been inconclusive. There have been debates and disagreements among scientific publications regarding the relationship between exercise and immune response against the causative agents of ARI. This narrative review aims to explore the theory that sufficiently explains the correlation between exercise, immune response, and ARI. The potential root causes of discrepancies come from research associated with the "open window" hypothesis. The studies have several limitations, and future improvements to address them are urgently needed in the study design, data collection, exercise intervention, subject recruitment, biomarkers for infection and inflammation, nutritional and metabolism status, and in addressing confounding variables. In conclusion, data support the clinical advantages of exercise have a regulatory contribution toward improving the immune response, which in turn potentially protects humans fromARI. However, the hypothesis related to its negative effect must be adopted cautiously.

The dose-response relationship between physical activity and the risk of death from pneumonia in middle-aged and older adults: A meta-analysis

BACKGROUND

Deaths from COVID-19 are concentrated in older adults, and studies have reported that physical activity (PA) can reduce the risk of death from pneumonia.

METHODS

Eight cohort studies and 2 case-control studies were included according to the inclusion and exclusion criteria established in this meta-analysis study followed the PRISMA guideline, 8 cohort studies and 2 case-control studies were finally included. Then, the research objects in these studies were classified to further study the dose-response relationship and non-dose-response relationship.

RESULTS

The highest dose of PA reduced the risk of death by 59% (risk ratio = 0.41; 95% confidence interval: 0.23-0.58) compared with the lowest dose of PA in middle-aged and elderly people. Furthermore, when the PA level was <10 m/wk, the risk of death from pneumonia was reduced by 6% every 4.5 MET-h/wk increase. At a PA level > 10 m/wk, the risk of death from pneumonia increased by 5% every 4.5 MET-h/wk increase. At a PA level > 30 m/wk, PA is a risk factor for pneumonia-related death in middle-aged and elderly people.

CONCLUSIONS

This meta-analysis showed that PA was associated with a reduced risk of dying from pneumonia in middle-aged and older adults, and that there was a significant nonlinear negative dose-response relationship between PA levels and the risk of dying from pneumonia. Therefore, moderate exercise was recommended.

The multifaceted benefits of walking for healthy aging: from Blue Zones to molecular mechanisms

Physical activity, including walking, has numerous health benefits in older adults, supported by a plethora of observational and interventional studies. Walking decreases the risk or severity of various health outcomes such as cardiovascular and cerebrovascular diseases, type 2 diabetes mellitus, cognitive impairment and dementia, while also improving mental well-being, sleep, and longevity. Dose-response relationships for walking duration and intensity are established for adverse cardiovascular outcomes. Walking's favorable effects on cardiovascular risk factors are attributed to its impact on circulatory, cardiopulmonary, and immune function. Meeting current physical activity guidelines by walking briskly for 30 min per day for 5 days can reduce the risk of several age-associated diseases. Additionally, low-intensity physical exercise, including walking, exerts anti-aging effects and helps prevent age-related diseases, making it a powerful tool for promoting healthy aging. This is exemplified by the lifestyles of individuals in Blue Zones, regions of the world with the highest concentration of centenarians. Walking and other low-intensity physical activities contribute significantly to the longevity of individuals in these regions, with walking being an integral part of their daily lives. Thus, incorporating walking into daily routines and encouraging walking-based physical activity interventions can be an effective strategy for promoting healthy aging and improving health outcomes in all populations. The goal of this review is to provide an overview of the vast and consistent evidence supporting the health benefits of physical activity, with a specific focus on walking, and to discuss the impact of walking on various health outcomes, including the prevention of age-related diseases. Furthermore, this review will delve into the evidence on the impact of walking and low-intensity physical activity on specific molecular and cellular mechanisms of aging, providing insights into the underlying biological mechanisms through which walking exerts its beneficial anti-aging effects.

The effect of lifestyle on the mortality associated with respiratory diseases in the general population

Lifestyle factors, including smoking habit, diet, and physical activity, affect the prognosis of various diseases. We elucidated the effect of lifestyle factors and health status on deaths from respiratory diseases in the general Japanese population using data from a community health examination database. Data of the nationwide screening program of the Specific Health Check-up and Guidance System (Tokutei-Kenshin), targeting the general population in Japan, from 2008 to 2010 were analyzed. The underlying causes of death were coded according to the International Classification of Diseases (ICD)-10. The hazard ratios of the incidence of mortality associated with respiratory disease were estimated using the Cox regression model. This study included 664,926 participants aged 40-74 years, who were followed up for 7 years. There were 8051 deaths, including 1263 (15.69%) deaths from respiratory diseases. The independent risk factors of mortality associated with respiratory diseases were male sex, older age, low body mass index, no exercise habit, slow walking speed, no drinking habit, smoking history, history of cerebrovascular diseases, high hemoglobin A1c and uric acid levels, low low-density lipoprotein cholesterol level, and proteinuria. Aging and decline of physical activity are significant risk factors for mortality associated with respiratory diseases, regardless of the smoking status.

Physical activity lowers the risk for acute respiratory infections: Time for recognition

Physical inactivity is a well-established risk factor for chronic diseases, such as cardiovascular disease, cancer, and diabetes mellitus. There is a growing awareness that physical inactivity should also be regarded as a risk factor for acute respiratory infections (ARIs). ARIs, such as the common cold, influenza, pneumonia, and coronavirus disease 2019 (COVID-19), are among the most pervasive diseases on earth and cause widespread morbidity and mortality. Evidence in support of the linkage between ARIs and physical inactivity has been strengthened during the COVID-19 pandemic because of increased scientific scrutiny. Large-scale studies have consistently reported that the risk for severe COVID-19 outcomes is elevated in cohorts with low physical activity and/or physical fitness, even after adjusting for other risk factors. The lowered risk for severe COVID-19 and other ARIs in physically active groups is attributed to exercise-induced immunoprotective effects, including enhanced surveillance of key immune cells and reduced chronic inflammation. Scientific consensus groups, including those who submitted the Physical Activity Guidelines for Americans, have not yet given this area of research the respect that is due. It is time to add "reduced risk for ARIs" to the "Exercise is Medicine" list of physical activity-related health benefits.

Social participation and change in walking time among older adults: a 3-year longitudinal study from the JAGES

BACKGROUND

Among all physical activities, walking is one of the easiest and most economical activities for older adults' mental and physical health. Although promoting social participation may extend the walking time of older adults, the longitudinal relationship is not well understood. Thus, this study elucidates the relationship between nine types of social participation and change in walking time during a 3-year follow-up of older adults.

METHODS

We conducted a 3-year community-based longitudinal study of independent older adults in Japan. From the 2016 and 2019 surveys, we extracted 57,042 individuals. We performed multiple regression analyses, estimating associations between change in walking time after three years and nine types of social participation in 2016: volunteer, sports, hobby, senior, neighborhood, learning, health, skills, and paid work. We conducted subgroup analysis stratified by walking time in 2016 (i.e., < 60 or ≥ 60 min/day).

RESULTS

The mean (standard deviation) change in walking time for 3 years was - 4.04 (29.4) min/day. After adjusting potential confounders, the significant predictors of increasing or maintaining walking time (min/day) were participation in paid work (+ 3.02) in the < 60 min/day subgroup; and volunteer (+ 2.15), sports (+ 2.89), hobby (+ 1.71), senior (+ 1.27), neighborhood (+ 1.70), learning (+ 1.65), health (+ 1.74), and skills (+ 1.95) in the ≥ 60 min/day subgroup compared with non-participants.

CONCLUSIONS

Paid work and community activities may be effective for maintaining or increasing walking time among older adults with less (< 60 min/day) and sufficient (≥ 60 min/day) walking time, respectively.

The Effects of Passive Simulated Jogging on Parameters of Explosive Handgrip in Nondiabetics and Type 2 Diabetics: A Single Arm Study

Aims

Type 2 diabetes (T2D) is associated with sarcopenia and decreased muscle strength. Explosive and isometric voluntary handgrip strengths (EHGS and HGS) are frequently utilized methods to ascertain health status and a marker of overall muscle strength. We have previously shown that a portable, motorized device, which produces effortless, rapid stepping in place (passive simulated jogging device (JD)), improves glucose homeostasis. This study quantitatively evaluated the effects of JD in modifying parameters of the modified EHGS curve in T2D and nondiabetic (ND) subjects.

Methods

Twenty-one adult participants (11 ND and 10 T2D) (mean age: 41.3 ± 13.5 yr) performed a modified explosive handgrip strength (EHGS) test on study day 1 followed by daily use of JD (90 min per day) for 7 days. The EHGS was repeated after 3 and 7 days' use of JD (JD3 and JD7) and 3 days after completion of JD (Carryover). EHGS curves were analyzed for the following: maximal peak force value (MAX); rate of force development at 25%,75%, and 90% of maximum force; and maximum force (RFD_25%, RFD_75%, RFD_90%, and RFD_max); time to 90%, 75%, and 25% of maximal force (t₉₀, t₇₅, t₂₅) and time to maximal force (t_max); and the integrated area under the curve for force vs. time until task failure (iAUC_TF); and fatigue resistance times at 50% and 25% of maximal force (FR₅₀ and FR25) and fatigue resistance time to task failure (FR_TF).

Results

At baseline, T2D had lower MAX compared to ND. There were no differences at baseline for force development time or fatigue resistance time between T2D and ND. In both T2D and ND, 7 days of JD increased FR₂₅ and FR_TF and iAUC_TF compared to baseline.

Conclusion

JD for at least 7 days prior to EHGS increased time to task failure (fatigue resistance) and iAUC_TF of the force-time curve. JD is a reasonable intervention to decrease sedentary behavior and improve muscle fatigue resistance under various clinical and nonclinical scenarios. This trial is registered with NCT03550105 (08-06-2018).

Physical activity reduces the risk of pneumonia: systematic review and meta-analysis of 10 prospective studies involving 1,044,492 participants

The beneficial effects of regular physical activity in promoting health and preventing chronic diseases are well documented. The relationship between regular physical activity and the risk of pneumonia is uncertain. We aimed to evaluate the magnitude and specificity of the prospective association between regular physical activity and the risk of pneumonia using a systematic review and meta-analysis of published observational cohort studies in general populations. Relevant studies with at least 1 year of follow-up were sought from inception until 15 September 2021 in MEDLINE, Embase, Web of Science, and manual search of relevant articles. Relative risks (RRs) with 95% confidence intervals (CIs) for the maximum versus the minimal amount of physical activity groups were pooled using fixed effects meta-analysis. The quality of the evidence was evaluated using the GRADE tool. A total of 10 prospective cohort studies comprising 1,044,492 participants and 7681 events were eligible. The pooled multivariable-adjusted RR (95% CI) of pneumonia comparing the most versus the least physically active groups was 0.69 (0.64–0.74). This association was significantly modified by type of outcome (p-value for meta-regression = .002): 0.82 (0.72–0.93) for incident pneumonia and 0.64 (0.59–0.70) for pneumonia-related mortality. There was no evidence of heterogeneity and publication bias. The GRADE quality of the evidence ranged from moderate to low. Aggregate analysis of 10 cohort studies shows that regular physical activity is associated with lowered risk of incident pneumonia and pneumonia-related mortality in the general population. Physical activity types that are attractive to and feasible for high-risk populations need to be identified and encouraged. Systematic review registration: PROSPERO 2021: CRD42021277514.

Peripheral Immune Dysfunction: A Problem of Central Importance after Spinal Cord Injury

Simple Summary

Spinal cord injury can result in an increased vulnerability to infections, but until recently the biological mechanisms behind this observation were not well defined. Immunosuppression and concurrent sustained peripheral inflammation after spinal cord injury have been observed in preclinical and clinical studies, now termed spinal cord injury-induced immune depression syndrome. Recent research indicates a key instigator of this immune dysfunction is altered sympathetic input to lymphoid organs, such as the spleen, resulting in a wide array of secondary effects that can, in turn, exacerbate immune pathology. In this review, we discuss what we know about immune dysfunction after spinal cord injury, why it occurs, and how we might treat it.

Abstract

Individuals with spinal cord injuries (SCI) exhibit increased susceptibility to infection, with pneumonia consistently ranking as a leading cause of death. Despite this statistic, chronic inflammation and concurrent immune suppression have only recently begun to be explored mechanistically. Investigators have now identified numerous changes that occur in the peripheral immune system post-SCI, including splenic atrophy, reduced circulating lymphocytes, and impaired lymphocyte function. These effects stem from maladaptive changes in the spinal cord after injury, including plasticity within the spinal sympathetic reflex circuit that results in exaggerated sympathetic output in response to peripheral stimulation below injury level. Such pathological activity is particularly evident after a severe high-level injury above thoracic spinal cord segment 6, greatly increasing the risk of the development of sympathetic hyperreflexia and subsequent disrupted regulation of lymphoid organs. Encouragingly, studies have presented evidence for promising therapies, such as modulation of neuroimmune activity, to improve regulation of peripheral immune function. In this review, we summarize recent publications examining (1) how various immune functions and populations are affected, (2) mechanisms behind SCI-induced immune dysfunction, and (3) potential interventions to improve SCI individuals’ immunological function to strengthen resistance to potentially deadly infections.

A prospective comparative study of the MNA-SF and GNRI nutritional screening tools in predicting infectious complications among elderly patients over 70 years undergoing posterior lumbar arthrodesis

Malnutrition is a risk factor for postoperative infectious complications of elderly patients undergoing posterior lumbar arthrodesis. At present, there is no gold standard for nutrition screening tools. We analyzed the value of predicting infectious complications among elderly patients over 70 years undergoing posterior lumbar arthrodesis by comparing the MNA-SF and GNRI. Demographic data, anthropometric measurements, serum albumin, surgical data and the occurrence of infectious complications and LOS were collected. Mini Nutritional Assessment short form (MNA-SF), Geriatric Nutritional Risk Index (GNRI) were performed within 24 h before surgery. Multivariable logistic regression analyses were used to identify predictors of infectious complications. The discriminatory performances of GNRI and MNA-SF scores for the occurrence of infectious complications were determined by receiver operating characteristic curves (ROC) analyses and the area under the curve (AUC). The study included 252 patients with a median age of 76.82 ± 6.41 years (range 70-84 years), and 142 patients (56.3%) were female. There were no significant differences in infectious complications (p = 0.236) and LOS (p = 0.580) among different GNRI categories. 27.3% malnourished patients evaluated by the MNA-SF suffered from infectious complications and 10.1% patients at risk of malnourished had infectious complications. Those patients had statistically significant higher prevalence of infectious complications (p = 0.002) and longer LOS (p = 0.023) than well-nourished patients. Multivariable analysis revealed that preoperative malnutrition and at risk of malnourished by the MNA-SF was significantly associated with infections. The area under the curve (AUC) of MNA-SF was 0.754, which was significantly high than AUC of GNRI (0.623) (Delong's test, p = 0.033). This study demonstrated that MNA-SF is a simple and effective tool for predicting the risk of infectious complications in elderly patients undergoing posterior lumbar arthrodesis.

Longer leisure walking time is associated with positive self-rated health among adults and older adults: a Brazilian nationwide study

Background

To verify the association between weekly leisure walking time and positive self-rated health in the Brazilian adult and elderly population.

Methods

This cross-sectional study used information collected in 2019 across all regions of Brazil. This study included 25,785 people aged ≥ 18 years (mean = 51.6; standard deviation = 18.0) from all capitals of the Brazilian states who reported practicing walking as physical activity during leisure time. Self-rated health was the dependent variable (positive or negative). The leisure walking time/week was the main exposure and it was categorized in “150 minutes/week”, “150–299 minutes/week” and “≥ 300 minutes/week”. We used binary logistic regression to estimate odds ratio (OR) and 95% confidence intervals (95% CI) that was adjusted for relevant covariates.

Results

We found that individuals who reported leisure walking for a period from 150 to 299 minutes/week and those who reported walking for a period ≥ 300 minutes/week were respectively 28% (OR = 1.28. 95% CI [1.10–1.48]) and 52% (OR = 1.52. 95% CI [1.27–1.82]) more likely of perceiving their health positively compared to those who reported walking for a period < 150 minutes/week. Individuals who reported leisure walking time <150 minutes/week had 72.3% (95% CI [70.4–74.1]) probability of perceiving their health positively. Individuals who reported leisure walking time from 150 to 299 minutes/week had 76.6% (95% CI [75.0 –78.3) probability of perceiving their health positively. On the other hand, individuals who reported leisure walking time ≥ 300 minutes/week had 79.2% probability (95% CI [77.1–81.4]) of perceiving their health positively.

Conclusion

Longer leisure walking time was associated with positive self-rated health among adults and older adults in Brazil.