Utility of pwc75% as an estimate of aerobic power in epidemiological and population-based studies

Tracking of Cardiorespiratory Fitness from Childhood to Mid-adulthood

High cardiorespiratory fitness (CRF) in adulthood is important for survival from major chronic diseases and preserving good health. We examined how childhood CRF tracks, or persists, into adulthood. Among a cohort of 748 school children followed over 34 years, we found child CRF correlated with young- (r = 0.30) and mid-adulthood (r = 0.16) CRF.

Exploring the direct and indirect effects of cardiovascular disease risk factors on exercise blood pressure

OBJECTIVE

Exaggerated exercise blood pressure (BP) is independently associated with cardiovascular disease (CVD) outcomes. However, it is unknown how individual CVD risk factors may interact with one another to influence exercise BP. The aim of this study was to quantify direct and indirect associations between CVD risk factors and exercise BP, to determine what CVD risk factor/s most-strongly relate to exercise BP.

METHODS

In a cross-sectional design, 660 participants (44 ± 2.6 years, 54% male) from the population-based Childhood Determinants of Adult Health Study had BP measured during low-intensity fixed-workload cycling. CVD risk factors were measured, including body composition, clinic (rest) BP, blood biomarkers, and cardiorespiratory fitness. Associations between CVD risk factors and exercise BP were assessed using linear regression, with direct and indirect pathways of association assessed via structural equation model.

RESULTS

Sex, waist-to-hip ratio, fitness, and clinic BP were independently associated with exercise systolic BP (SBP), and along with age, had direct associations with exercise SBP (p < 0.05 all). Most CVD risk factors were indirectly associated with exercise SBP via a relation with clinic BP (p < 0.05 all). Clinic BP, waist-to-hip ratio, and fitness were most-strongly associated (direct and indirect association) with exercise SBP (β[95% CI]: 9.35 [8.04, 10.67], 4.91 [2.56, 7.26], and -2.88 [-4.25, -1.51] mm Hg/SD, respectively).

CONCLUSION

Many CVD risk factors are associated with exercise BP, mostly with indirect effects via clinic BP. Clinic BP, body composition, and fitness were most-strongly associated with exercise BP. These results may elucidate how lifestyle modification could be a primary strategy to decrease exaggerated exercise BP-related CVD risk.

ECG Ventricular Repolarization Dynamics during Exercise: Temporal Profile, Relation to Heart Rate Variability and Effects of Age and Physical Health

Periodic repolarization dynamics (PRD) is a novel electrocardiographic marker of cardiac repolarization instability with powerful risk stratification capacity for total mortality and sudden cardiac death. Here, we use a time-frequency analysis approach to continuously quantify PRD at rest and during exercise, assess its dependence on heart rate variability (HRV) and characterize the effects of age (young adults/middle-aged adults/older adults), body mass index (non-overweight/overweight) and cardiorespiratory fitness level (fit/unfit). Sixty-six male volunteers performed an exercise test. RR and dT variabilities (RRV, dTV), as well as the fraction of dT variability unrelated to RR variability, were computed based on time-frequency representations. The instantaneous LF power of dT (PdTV), representing the same concept as PRD, and of its RRV-unrelated component (PdTVuRRV) were quantified. dT angle was found to mostly oscillate in the LF band. Overall, 50-70% of PdTV was linearly unrelated to RRV. The onset of exercise caused a sudden increase in PdTV and PdTVuRRV, which returned to pre-exercise levels during recovery. Clustering analysis identified a group of overweight and unfit individuals with significantly higher PdTV and PdTVuRRV values at rest than the rest of the population. Our findings shed new light on the temporal profile of PRD during exercise, its relationship to HRV and the differences in PRD between subjects according to phenotypic characteristics.

Validity of the Polar H7 Heart Rate Sensor for Heart Rate Variability Analysis during Exercise in Different Age, Body Composition and Fitness Level Groups

This work aims to validate the Polar H7 heart rate (HR) sensor for heart rate variability (HRV) analysis at rest and during various exercise intensities in a cohort of male volunteers with different age, body composition and fitness level. Cluster analysis was carried out to evaluate how these phenotypic characteristics influenced HR and HRV measurements. For this purpose, sixty-seven volunteers performed a test consisting of the following consecutive segments: sitting rest, three submaximal exercise intensities in cycle-ergometer and sitting recovery. The agreement between HRV indices derived from Polar H7 and a simultaneous electrocardiogram (ECG) was assessed using concordance correlation coefficient (CCC). The percentage of subjects not reaching excellent agreement (CCC > 0.90) was higher for high-frequency power (PHF) than for low-frequency power (PLF) of HRV and increased with exercise intensity. A cluster of unfit and not young volunteers with high trunk fat percentage showed the highest error in HRV indices. This study indicates that Polar H7 and ECG were interchangeable at rest. During exercise, HR and PLF showed excellent agreement between devices. However, during the highest exercise intensity, CCC for PHF was lower than 0.90 in as many as 60% of the volunteers. During recovery, HR but not HRV measurements were accurate. As a conclusion, phenotypic differences between subjects can represent one of the causes for disagreement between HR sensors and ECG devices, which should be considered specifically when using Polar H7 and, generally, in the validation of any HR sensor for HRV analysis.

Domain-specific physical activity patterns and cardiorespiratory fitness among the working population: Findings from the cross-sectional German Health Interview and Examination Survey

OBJECTIVES

This study aimed to investigate associations between occupational physical activity patterns (physical work demands linked to job title) and leisure time physical activity (assessed by questionnaire) with cardiorespiratory fitness (assessed by exercise test) among men and women in the German working population.

DESIGN

Population-based cross-sectional study.

SETTING

Two-stage cluster-randomised general population sample selected from population registries of 180 nationally distributed sample points. Information was collected from 2008 to 2011.

PARTICIPANTS

1296 women and 1199 men aged 18-64 from the resident working population.

OUTCOME MEASURE

Estimated low maximal oxygen consumption ([Formula: see text]), defined as first and second sex-specific quintile, assessed by a standardised, submaximal cycle ergometer test.

RESULTS

Low estimated [Formula: see text] was strongly linked to low leisure time physical activity, but not occupational physical activity. The association of domain-specific physical activity patterns with low [Formula: see text] varied by sex: women doing no leisure time physical activity with high occupational physical activity levels were more likely to have low [Formula: see text] (OR 6.54; 95% CI 2.98 to 14.3) compared with women with ≥2 hours of leisure time physical activity and high occupational physical activity. Men with no leisure time physical activity and low occupational physical activity had the highest odds of low [Formula: see text] (OR 4.37; 95% CI 2.02 to 9.47).

CONCLUSION

There was a strong association between patterns of leisure time and occupational physical activity and cardiorespiratory fitness within the adult working population in Germany. Women doing no leisure time physical activity were likely to have poor cardiorespiratory fitness, especially if they worked in physically demanding jobs. However, further investigation is needed to understand the relationships between activity and fitness in different domains. Current guidelines do not distinguish between activity during work and leisure time, so specifying leisure time recommendations by occupational physical activity level should be considered.

Individual and interpersonal correlates of cardiorespiratory fitness in adults - Findings from the German Health Interview and Examination Survey

Cardiorespiratory fitness (CRF) is an established predictor of adverse health outcomes. The aim of this study is to investigate potential behavioral, interpersonal and socioeconomic correlates of CRF among men and women living in Germany using data from a population-based nationwide cross-sectional study. 1,439 men and 1,486 women aged 18-64 participated in the German Health Interview and Examination Survey (2008-2011) and completed a standardized sub-maximal cycle ergometer test. Maximal oxygen consumption ([Formula: see text]) in ml·min-1·kg-1 was estimated. Mean values of VO2max for various anthropometric, behavioral, interpersonal, and sociodemographic variables were estimated. Linear regression analyses using multiple imputations technique for missing values was performed to analyze the influence of potential correlates on CRF. Women with high alcohol consumption had higher [Formula: see text], (β = 2.20; 95% CI 0.98 to 3.42) than women with low alcohol consumption and women with high occupational status had higher [Formula: see text] (β = 1.83; 95% CI 0.21 to 3.44) in comparison to women with low occupational status. Among men, high fruit intake (β = 1.52; 95% CI 0.63 to 2.40), compared to low or medium fruit intake and performing at least 2.5 hours of total PA per week (β = 2.19; 95% CI 1.11 to 3.28), compared to less than 2.5 hours was associated with higher [Formula: see text]. Among both men and women, lower body mass index, lower waist circumference and higher levels of physical exercise were considerably associated with higher [Formula: see text]. Among women, those in higher age groups showed a considerably lower level of [Formula: see text] compared with those aged 18-24. Furthermore, mean estimated [Formula: see text] was higher among men (36.5; 95% CI 36.0 to 37.0) than among women (30.3; 95% CI 29.8 to 30.7). Despite the cross-sectional nature of the current study, we conclude that several behavioral, anthropometric, and sociodemographic factors are associated with CRF in the general adult population in Germany. These results can provide evidence to tailor prevention measures according to the needs of specific subgroups.

Validity and reliability evidence of a point of care assessment of salivary cortisol and α-amylase: a pre-registered study

PURPOSE

The iPro Cube is a small portable point-of-care device designed to analyse salivary markers of stress in a user-friendly manner (e.g., fast, convenient). Our aim was to test the reliability and validity of the iPro Cube to measure salivary cortisol and α-amylase as compared to the common laboratory standard method (ELISA immunoassay) prior to and after moderate intensity exercise.

METHODS

The study was a repeated measures, pre-registered design, and statistical framework that incorporated prior knowledge directly into the estimation process. Twenty-nine individuals (age = 27.4 ± 6.6 y; body-mass = 70.8 ± 11.3 kg; height = 1.74 ± 0.92 m; 18 males) completed a single PWC75%HRmax, with repeated measures of salivary cortisol and -amylase pre, immediately post, and 30 min post-exercise.

RESULTS

Correlation between the iPro Cube and laboratory-based assessments of salivary cortisol was moderate-to-large (0.53 > r < 0.81) across all three testing points. In contrast, correlation between the iPro Cube and laboratory-based assessments of -amylase was small-to-moderate (0.25 > r < 0.46). We found a large correlation between duplicate samples of iPro Cube cortisol assessment (0.75 > r < 0.82), and a moderate-to-large correlation for -amylase (0.51> r < 0.77).

CONCLUSIONS

The iPro Cube is capable of taking measures of salivary cortisol that are moderately correlated to values obtained via ELISA immunoassay, however the unit underestimates salivary cortisol and overestimates salivary -amylase at rest and post-moderate intensity exercise. It is recommended that researchers continue using standard laboratory techniques to assess these salivary stress markers.

[Reference Values for Cardiorespiratory Fitness of the General Population: The German National Health Interview and Examination Survey for Adults (DEGS1) 2008-2011]

AIM OF STUDY

This study aims to provide population-based reference values for heart rate-based indicators of cardiorespiratory fitness for adults with physical activity readiness aged 18 to 64 years living in Germany.

METHODS

Based on data on 2,826 individuals who participated in a submaximal cycle ergometer exercise test as part of the German National Health Interview and Examination Survey for Adults (DEGS1) between 2008 and 2011, we calculated the following indicators: physical working capacity at 150 and 130 beats/min and at 75% of estimated maximum heart rate (PWC150, PWC130 and PWC75%) as well as heart rate-based estimated maximum oxygen uptake (VO₂max). We used the LMS method by Cole & Green 1992 to calculate reference values.

RESULTS

25^th, 50^th and 75^th percentiles of PWC150 were 1.5, 1.77 and 2.08 watts/kg among men and 1.18, 1.44 and 1.69 among women. 25^th, 50^th and 75^th percentiles of PWC130 were 1.16, 1.41 and 1.68 watts/kg among men and 0.81, 1.05 and 1.29 among women. Age-dependent median PWC75% values among men and women were 1.87 - age in years× 0.01 and 1.31 - (age in years/100)²× 0.98, respectively, and VO₂max among men is 41.7 - age× 0.15.

CONCLUSIONS

The references values presented can be used for individual rating of cardiorespiratory fitness among adults living in Germany. Furthermore, they can serve as a basis for regular monitoring purposes.

Association between cardiorespiratory fitness and colorectal cancer in the UK Biobank

Increased cardiorespiratory fitness is related to decreased risk of major chronic illnesses, including cardiovascular disease, type 2 diabetes, and cancer, but its association with colorectal cancer specifically has received very little attention. We examined the relation of cardiorespiratory fitness to colorectal cancer in 59,191 UK Biobank participants aged 39-70 years without prevalent cancer at baseline, followed from 2009 to 2014. Submaximal bicycle ergometry was conducted at study entry, and cardiorespiratory fitness was defined as physical work capacity at 75% of the maximum heart rate, standardised to body mass (PWC_75%). Multivariable Cox proportional hazards regression was performed to obtain hazard ratios (HR) and corresponding 95% confidence intervals (CI). During a mean follow-up of 4.6 years, 232 participants developed colorectal cancer (151 colon cancers; 79 rectal cancers). When comparing the 75th to the 25th percentiles of PWC_75%, the multivariable-adjusted HR of colorectal cancer was 0.78 (95% CI 0.62-0.97). That relation was largely driven by an inverse association with colon cancer (HR 0.74, 95% CI 0.56-0.97) and less so with rectal cancer (HR 0.88, 95% CI 0.62-1.26; p value for difference by colorectal cancer endpoint = 0.056). The inverse relation of cardiorespiratory fitness with colorectal cancer was more evident in men (HR 0.72, 95% CI 0.55-0.94) than women (HR 0.99, 95% CI 0.71-1.38), although the gender difference was not statistically significant (p value for interaction = 0.192). Increased cardiorespiratory fitness is associated with decreased risk of colorectal cancer. Potential heterogeneity by colorectal cancer anatomic subsite and gender requires further study.

Body composition, nutritional status, and endothelial function in physically active men without metabolic syndrome--a 25 year cohort study

BACKGROUND

The purpose of this analysis was to investigate the relationship between body composition, metabolic parameters and endothelial function among physically active healthy middle-aged and older men.

METHODS

Out of 101 asymptomatic men prospectively tracked for traditional cardiovascular risk factors (mean observation period 25.1 years), 55 metabolically healthy individuals who maintained stable leisure time physical activity (LTPA) level throughout the observation and agreed to participate in the body composition assessment were recruited (mean age 60.3 ± 9.9 years). Body composition and raw bioelectrical parameters were measured with bioelectrical impedance analysis (BIA). Microvascular endothelial function was evaluated by means of the reactive hyperemia index (RHI) using Endo-PAT2000 system.

RESULTS

Strong correlations were observed between lifetime physical activity (PA), aerobic fitness and most of analyzed body composition parameters. The strongest inverse correlation was found for fat mass (p < 0.01) while positive relationship for fat-free mass (p < 0.01), total body water (p < 0.05 for current aerobic capacity and p < 0.01 for historical PA), body cell mass (p < 0.001), muscle mass (p < 0.001), calcium and potassium (p < 0.01 and p < 0.001 for current aerobic capacity and p < 0.001 and p < 0.01 for historical PA, respectively) and glycogen mass (p < 0.001). Among metabolic parameters, HDL cholesterol (HDL-C) and uric acid were significantly associated with most body composition indicators. Regarding endothelial function, a negative correlation was found for RHI and body mass (p < 0.05) while positive relationship for RHI and body cell mass (p < 0.05), calcium (p < 0.05) and potassium mass (p < 0.05). Impaired endothelial function was observed among 8 subjects. Among bioelectrical parameters, impedance (Z) and resistance (R) normalized for subjects' height were negatively related with body mass, body mass index (BMI) and waist circumference (p < 0.001); while reactance (Xc) normalized for patients' height was negatively related with body mass (p < 0.05). The mean phase angle value was relatively high (8.83 ± 1.22) what reflects a good level of cellularity and cell function. Phase angle was positively related with body mass and BMI (p < 0.05).

CONCLUSIONS

Both fat mass and muscle mass components are important predictors of metabolic profile. Maintaining regular high PA level and metabolically healthy status through young and middle adulthood may have beneficial influence on body composition parameters and may prevent age-related decrease of fat-free mass and endothelial dysfunction.

Regular physical activity and cardiovascular biomarkers in prevention of atherosclerosis in men: a 25-year prospective cohort study

Background

The purpose of the study was to examine the association between leisure-time physical activity (LTPA), cardiovascular biomarkers and atherosclerosis among asymptomatic men with stable LTPA level throughout the 25-year prospective observation.

Methods

Out of 101 asymptomatic men prospectively observed for their lifestyle and cardiovascular risk factors, the cohort of 62 individuals (mean age 59.9 years) maintained a stable LTPA level during the 25-year observation. Regular check-ups with the assessment of traditional risk factors, detailed measurements of LTPA level and aerobic capacity were performed since baseline. At the latest follow-up (2011/12) a set of cardiovascular biomarkers was measured using enzyme-linked immunosorbent assay. Subclinical atherosclerosis was assessed by means of coronary artery calcification score and intima-media thickness (IMT). Endothelial function was evaluated by means of the reactive hyperemia index. The studied biomarkers and indices were analyzed in the three cohorts representing stable low-tomoderate (<2050 kcal/week), high (2050-3840 kcal/week) and very high LTPA (>3840 kcal/week).

Results

At baseline the three cohorts were comparable in terms of age and clinical characteristics. At follow-up, the cohort with stable high LTPA (2050-3840 kcal/week) had significantly lower concentrations of hs-CRP (2.20 ± 1.0 mg/L), oxidized-LDL (68.35 ± 67.7 ng/mL), leptin (4.71 ± 3.07 ng/mL) and irisin (0.47 ± 0.13 μmol/L), and the most favorable indices of atherosclerosis and endothelial function as compared with other groups (p < 0.05). Regular marathon runners had increased concentrations of hsCRP (3.12 ± 1.4 mg/L), oxidized-LDL (249.8 ± 129 ng/ml), Interleukine-6 (3.74 ± 2.4 pg/ml). A positive correlation was observed between hsCRP and IMT (r = 0.301; p < 0.01), and irisin and IMT (r = 0.223; p < 0.05).

Conclusions

The data suggest that stable high LTPA (2050-3840 kcal/week) is associated with the most favorable profile of key cardiovascular biomarkers and indices of atherosclerosis. Lifetime very high LTPA is associated with increased lowgrade inflammation and may, therefore, exert an atherogenic effect.

The impact of long-term changes in metabolic status on cardiovascular biomarkers and microvascular endothelial function in middle-aged men: a 25-year prospective study

BACKGROUND

The aim of this analysis was to examine long-term effects of changes in metabolic status on microvascular endothelial function and cardiovascular diseases (CVD) biomarkers among physically active middle-aged men.

METHODS

Metabolically healthy men (n = 101, mean age 59.7 years), free of symptoms and treatment, have been prospectively observed for their lifestyle and CVD risk factors (observation period 24.7 years). At the latest follow-up (2011/2012) a set of CVD biomarkers was measured using enzyme-linked immunosorbent assay. Microvascular endothelial function was evaluated by means of the reactive hyperemia index (RHI) using Endo-PAT2000 system. At follow-up the participants were divided into metabolically healthy (0-1 metabolic parameters) and metabolically unhealthy (≥2 metabolic parameters) groups. Metabolic syndrome was defined according to the NCEP ATP III definition.

RESULTS

Traditional metabolic risk factors were significantly associated with hsCRP, ox-LDL, Il-6, leptin and adiponectin/leptin ratio. Reactive hyperemia index was negatively related to body mass (p < 0.01), waist circumference (p < 0.05), triglycerides (p < 0.01), TG/HDL ratio (p < 0.01), uric acid (p < 0.05), sICAM-1 (p < 0.05) and Il-6 (p < 0.05), and positively to HDL-C (p < 0.01) and leisure-time physical activity (p < 0.01). Men who maintained metabolically healthy status (n = 47) through the observation had significantly lower hsCRP and uric acid (p < 0.05), higher adiponectin/leptin ratio (p < 0.05), higher mean RHI and lower prevalence of endothelial dysfunction (p < 0.05) as compared to the metabolically unhealthy group (n = 54). Regular physical activity level was significantly higher among metabolically healthy individuals during the whole observation.

CONCLUSIONS

Even subtle changes in metabolic profile influence inflammatory biomarkers and microvascular endothelial function. Leptin, adiponectin/leptin ratio and hsCRP are significant predictors of metabolic profile. Interleukine-6 and sICAM-1 may be used as indicators of early endothelial dysfunction in asymptomatic men. High leisure-time physical activity level is an important contributor of metabolically healthy profile through middle adulthood.

Physical Activity, Aerobic Capacity, and Total Antioxidant Capacity in Healthy Men and in Men with Coronary Heart Disease

OBJECTIVE

The purpose of the study was to assess total antioxidant capacity (TAC) of blood serum in relation with habitual leisure time physical activity (LTPA) and aerobic capacity in a group of 90 men with coronary heart disease (CHD) aged 34.8-77.0 years and in 90 age-matched peers without CHD.

METHODS

Two spectrophotometric methods were applied to assess TAC: Ferric Reducing Ability of Serum (TAC-FRAS) and 2.2-diphenyl-1-picryl-hydrazyl (TAC-DPPH) tests. Aerobic capacity was expressed as physical working capacity at 85% of the maximal heart rate (PWC(85%HRmax)).

RESULTS

CHD patients had higher values of TACFRAS (1.37 ± 0.28 versus 1.27 ± 0.23 mmol FeCl2·L(-1); P < 0.05) but there were no group differences for TAC-DPPH and for uric acid (UA). Negative correlation was found between LTPA (also when calculated per kg of body mass) and TAC-DPPH in CHD patients. In CHD patients, TAC-FRAS and UA were lower in subjects with higher aerobic capacity expressed as PWC(85%HRmax/kg). Those associations were not found in healthy men.

CONCLUSIONS

We conclude that TAC of blood serum is moderately adversely related to LTPA and aerobic capacity in patients with CHD. UA, as the main determinant of serum TAC, may be partially responsible for those associations.

Association between self-reported and objectively measured physical fitness level in a middle-aged population in primary care

Aim

To investigate the association between self-reported physical fitness level obtained by a single-item question and objectively measured fitness level in 30- to 49-year-old men and women.

Methods

From the Danish ‘Check Your Health Preventive Program’ 2013–2014 fitness level was assessed in 2316 participants using the Aastrand test. Additionally, participants rated their physical fitness as high, good, average, fair or low. The association of self-reported- with objectively measured fitness level was analyzed by linear regression. Categories of self-reported- and objectively measured fitness level were cross-tabulated and agreement was quantified by Kappa statistics. Gender differences within categories were investigated by Poisson regression.

Results

Data from 996 men and 1017 women were analyzed (excluded, n = 303). In both men and women a higher self-reported fitness level was associated with a higher objectively measured fitness level (R_all = 0.42). Kappa agreement was 0.25. Poisson regression revealed that women rated their fitness level significantly lower than men (p < 0.001).

Conclusion

A single-item question is a cost-effective way of measuring physical fitness level, but the method has low association and fair agreement when compared to the Aastrand test. Men tend to overestimate physical fitness more than women, which should be accounted for if using the question in primary care settings.

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A higher self-reported fitness level was associated with a higher objectively measured fitness level.

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The agreement between self-reported- and objectively measured physical fitness level was fair.

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Both men and women overestimated physical fitness level although more pronounced in men.

Effect of cardiovascular training on fitness and perceived disease activity in people with ankylosing spondylitis

OBJECTIVE

Several studies suggest that patients with ankylosing spondylitis (AS) have an increased risk of cardiovascular disease. This study aimed to evaluate the effects of a 12-week, individually monitored, with moderate heart rate level intensity cardiovascular training on cardiovascular fitness and perceived disease activity in AS patients.

METHODS

Patients diagnosed with AS according to the modified New York criteria were randomized to either cardiovascular training or attention control. The training group performed 3 cardiovascular training units per week. All participants attended 1 weekly usual care flexibility training session. Attention control contained regular discussion groups on coping strategies. Adherence was self-monitored. Assessments were performed at baseline and after the intervention period of 3 months. Physical fitness was the primary end point, measured in watts using a submaximal bicycle test following the physical work capacity 75% protocol. All analyses controlled for sex, age, body mass index,baseline fitness and physical activity levels, and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI).

RESULTS

Of 106 AS patients enrolled, 40% were women and the mean ± SD age was 49 ± 12 years. A total of 74.6% of the training group reported exercising at least 3 times a week. At the 3-month followup, the fitness level in the training group was significantly higher than in the control group (mean ± SE 90.32W ± 4.52W versus 109.84W ± 4.72W; P = 0.001), independent of other covariates. The mean BASDAI total score was 0.31 points lower (P = 0.31) in the training group, reaching significance for the peripheral pain subscore (1.19; P = 0.01) but not for back pain or fatigue.

CONCLUSION

Cardiovascular training, in addition to flexibility exercise, increased fitness in AS patients and reduced their peripheral pain.

[Measurement of cardiorespiratory fitness in the German Health Interview and Examination Survey for Adults (DEGS1)]

A state of good fitness is related to a better health state and a lower mortality risk. In the German Health Interview and Examination Survey for Adults (DEGS1), aerobic fitness was measured among adults between 18 and 64 years old using a submaximal cycle ergometry test. The total sample comprised 5,263 persons, amongst those 3,111 were categorized as being test-qualified according to the Physical Activity Readiness-Questionnaire. There were 3,030 persons who absolved a submaximal exercise test according to the exercise protocol of the WHO (25/25/2). The test-participation rate was 57.2 % in relation to the total sample and 97.4 % among test-qualified persons. Apart from the continuous heart-rate monitoring, capillary blood was taken prior to starting the test and at the end of each workload stage for performing blood lactate analyses. The test ended when 85 % of the age-predicted maximal heart rate was exceeded. In all 11.9 % of the tests were terminated earlier, the mean exercise duration was 10.8 min, and the anticipated submaximal exertion in the highest workload stage was on average achieved with a mean of 15 on the 20-point RPE scale. The nationwide data can now be used for the national health monitoring system, epidemiological research and for the calculation of reference values. An English full-text version of this article is available at SpringerLink as supplemental.

A single bout of aerobic exercise promotes motor cortical neuroplasticity

Regular physical activity is associated with enhanced plasticity in the motor cortex, but the effect of a single session of aerobic exercise on neuroplasticity is unknown. The aim of this study was to compare corticospinal excitability and plasticity in the upper limb cortical representation following a single session of lower limb cycling at either low or moderate intensity, or a control condition. We recruited 25 healthy adults to take part in three experimental sessions. Cortical excitability was examined using transcranial magnetic stimulation to elicit motor-evoked potentials in the right first dorsal interosseus muscle. Levels of serum brain-derived neurotrophic factor and cortisol were assessed throughout the experiments. Following baseline testing, participants cycled on a stationary bike at a workload equivalent to 57% (low intensity, 30 min) or 77% age-predicted maximal heart rate (moderate intensity, 15 min), or a seated control condition. Neuroplasticity within the primary motor cortex was then examined using a continuous theta burst stimulation (cTBS) paradigm. We found that exercise did not alter cortical excitability. Following cTBS, there was a transient inhibition of first dorsal interosseus motor-evoked potentials during control and low-intensity conditions, but this was only significantly different following the low-intensity state. Moderate-intensity exercise alone increased serum cortisol levels, but brain-derived neurotrophic factor levels did not increase across any condition. In summary, low-intensity cycling promoted the neuroplastic response to cTBS within the motor cortex of healthy adults. These findings suggest that light exercise has the potential to enhance the effectiveness of motor learning or recovery following brain damage.

Testing the activitystat hypothesis: a randomised controlled trial protocol

BACKGROUND

The activitystat hypothesis proposes that when physical activity or energy expenditure is increased or decreased in one domain, there will be a compensatory change in another domain to maintain an overall, stable level of physical activity or energy expenditure. To date, there has been no experimental study primarily designed to test the activitystat hypothesis in adults. The aim of this trial is to determine the effect of two different imposed exercise loads on total daily energy expenditure and physical activity levels.

METHODS

This study will be a randomised, multi-arm, parallel controlled trial. Insufficiently active adults (as determined by the Active Australia survey) aged 18-60 years old will be recruited for this study (n=146). Participants must also satisfy the Sports Medicine Australia Pre-Exercise Screening System and must weigh less than 150 kg. Participants will be randomly assigned to one of three groups using a computer-generated allocation sequence. Participants in the Moderate exercise group will receive an additional 150 minutes of moderate to vigorous physical activity per week for six weeks, and those in the Extensive exercise group will receive an additional 300 minutes of moderate to vigorous physical activity per week for six weeks. Exercise targets will be accumulated through both group and individual exercise sessions monitored by heart rate telemetry. Control participants will not be given any instructions regarding lifestyle. The primary outcome measures are activity energy expenditure (doubly labeled water) and physical activity (accelerometry). Secondary measures will include resting metabolic rate via indirect calorimetry, use of time, maximal oxygen consumption and several anthropometric and physiological measures. Outcome measures will be conducted at baseline (zero weeks), mid- and end-intervention (three and six weeks) with three (12 weeks) and six month (24 week) follow-up. All assessors will be blinded to group allocation.

DISCUSSION

This protocol has been specifically designed to test the activitystat hypothesis while taking into account the key conceptual and methodological considerations of testing a biologically regulated homeostatic feedback loop. Results of this study will be an important addition to the growing literature and debate concerning the possible existence of an activitystat.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12610000248066.

German health interview and examination survey for adults (DEGS) - design, objectives and implementation of the first data collection wave

BACKGROUND

The German Health Interview and Examination Survey for Adults (DEGS) is part of the recently established national health monitoring conducted by the Robert Koch Institute. DEGS combines a nationally representative periodic health survey and a longitudinal study based on follow-up of survey participants. Funding is provided by the German Ministry of Health and supplemented for specific research topics from other sources.

METHODS/DESIGN

The first DEGS wave of data collection (DEGS1) extended from November 2008 to December 2011. Overall, 8152 men and women participated. Of these, 3959 persons already participated in the German National Health Interview and Examination Survey 1998 (GNHIES98) at which time they were 18-79 years of age. Another 4193 persons 18-79 years of age were recruited for DEGS1 in 2008-2011 based on two-stage stratified random sampling from local population registries. Health data and context variables were collected using standardized computer assisted personal interviews, self-administered questionnaires, and standardized measurements and tests. In order to keep survey results representative for the population aged 18-79 years, results will be weighted by survey-specific weighting factors considering sampling and drop-out probabilities as well as deviations between the design-weighted net sample and German population statistics 2010.

DISCUSSION

DEGS aims to establish a nationally representative data base on health of adults in Germany. This health data platform will be used for continuous health reporting and health care research. The results will help to support health policy planning and evaluation. Repeated cross-sectional surveys will permit analyses of time trends in morbidity, functional capacity levels, disability, and health risks and resources. Follow-up of study participants will provide the opportunity to study trajectories of health and disability. A special focus lies on chronic diseases including asthma, allergies, cardiovascular conditions, diabetes mellitus, and musculoskeletal diseases. Other core topics include vaccine-preventable diseases and immunization status, nutritional deficiencies, health in older age, and the association between health-related behavior and mental health.

Physical activity and total antioxidant capacity across an adult lifespan of men

PURPOSE

The aim of the study was to determine the association between the long-term physical activity (PA) and the total antioxidant capacity (TAC) of blood serum and their association with coexisting risk factors of cardiometabolic diseases in a group of relatively healthy men.

METHODS

The research was conducted among 422 males age 19.2-89.8 yr, either sedentary or involved in recreational sports activities. Anthropometric measurements, lipid profile, and measurement of glucose and uric acid levels were performed in every man. Current PA, historical PA, and aerobic fitness (physical working capacity) were assessed. TAC was determined with two spectrophotometric methods: the ferric reducing ability of serum (TAC-FRAS) and 2,2-diphenyl-1-picryl-hydrazyl (TAC-DPPH) tests.

RESULTS

TAC was not related to the age of the subjects. Higher current and historical PA were associated with a more favorable cardiometabolic risk profile but not TAC. In fact, current PA level was connected with lower values of TAC-FRAS. Values of both TAC-FRAS and TAC-DPPH decreased with an increase of aerobic capacity. Individuals with coexisting anthropometric and biochemical risk factors of cardiovascular diseases and with elevated values of arterial pressure had higher TAC. Values of both TAC-FRAS (r = 0.66) and TAC-DPPH (r = 0.39) were strongly positively correlated with uric acid level.

CONCLUSIONS

Overweight, obesity, higher blood pressure, unfavorable blood lipid profile, and especially higher uric acid levels are connected with greater TAC of blood serum across an adult man's life. High PA and fitness are associated with a more favorable overall risk profile of cardiovascular and metabolic diseases but are related to lower TAC.

Preoperative therapeutic programme for elderly patients scheduled for elective abdominal oncological surgery: a randomized controlled pilot study

Objective: Investigation of the feasibility and preliminary effect of a short-term intensive preoperative exercise programme for elderly patients scheduled for elective abdominal oncological surgery.

Design: Single-blind randomized controlled pilot study.

Setting: Ordinary hospital in the Netherlands.

Subjects: Forty-two elderly patients (>60 years).

Interventions: Patients were randomly assigned to receive a short-term intensive therapeutic exercise programme to improve muscle strength, aerobic capacity, and functional activities, given in the outpatient department (intervention group; n =22), or home-based exercise advice (control group; n=20).

Main measures: Parameters of feasibility, preoperative functional capacity and postoperative course.

Results: The intensive training programme was feasible, with a high compliance and no adverse events. Respiratory muscle endurance increased in the preoperative period from 259 ± 273 to 404 ± 349 J in the intervention group and differed significantly from that in the control group (350 ± 299 to 305 ± 323 J; P<0.01). Timed-Up-and-Go, chair rise time, LASA Physical Activity Questionnaire, Physical Work Capacity and Quality of Life (EORTC-C30) did not reveal significant differences between the two groups. There was no significant difference in postoperative complications and length of hospital stay between the two groups.

Conclusion: The intensive therapeutic exercise programme was feasible and improved the respiratory function of patients due to undergo elective abdominal surgery compared with home-based exercise advice.

The influence of fitness on insulin resistance in obese children

An increasingly pervasive environment of reduced activity and easy access to high caloric food is leading to an epidemic of poor cardiovascular fitness, obesity, insulin resistance and type 2 diabetes (T2DM) in children. Studies have shown that insulin resistance (IR) to be an independent predictor for morbidity as well as mortality. These serve as a strong stimulus for public health strategies to improve fitness in children and adolescents. Methods to assess IR, improve IR and understand complications are increasingly important in children.

Submaximal treadmill test predicts VO2max in overweight children

OBJECTIVE

To demonstrate the ability of a submaximal test to predict VO(2max) in overweight children.

STUDY DESIGN

A total of 130 children, 11 to 14 years old, with body mass index >85 percentile for age and sex performed a submaximal walking test. VO(2max) was measured by using open circuit spirometry during a graded exercise test to volitional fatigue. An equation to predict VO(2max) was modeled by using the variables of sex, weight (kg), height (cm), heart rate (HR) after 4 minutes during the submaximal test (4minHR), HR difference (4minHR - resting HR), and submaximal treadmill speed (miles per hour [mph]) in 75% of the subjects. Validation was performed by using the remaining 25% of subjects.

RESULTS

A total of 113 subjects achieved a maximal effort and was used in the statistical analysis. Development and validation groups were similar in all aspects. On validation, the mean square error was 241.06 with the predicted VO(2max) within 10% of the observed value in 67% of subjects.

CONCLUSION

VO(2max) was accurately predicted in this cohort of overweight children by using a submaximal, treadmill-based testing protocol.

The effects of exercise and nicotine replacement therapy on smoking rates in women

PURPOSE

To examine the individual effects of supervised and intensive exercise as well as the combined effects of exercise and nicotine replacement therapy (NRT) on (a) smoking cessation and reduction rates and (b) psychological and physiological processes during withdrawal.

METHODS

One-hundred and forty-two inactive female smokers were randomised into the following four groups: exercise+nicotine patch; exercise+no nicotine patch; cognitive behavior therapy (CBT)+nicotine patch and CBT+no nicotine patch. Smoking abstinence (verified by saliva cotinine and expired carbon monoxide), cessation self-efficacy, and physical fitness and body weight were assessed at baseline (week 1), quit date (week 6), program termination (week 12), and 3- and 12-month follow-up.

RESULTS

There were significant differences in a 7-day point prevalence but not continuous abstinence rates between treatment groups across targeted end points. Consistently higher cessation rates were seen when NRT was added to both treatment programs. Compared with CBT participants, exercise participants had significantly increased functional exercise capacity and had gained significantly less weight during program end points but these differences did not hold at a 12-month follow-up. Compared with exercise participants, CBT participants felt greater cessation efficacy and reported greater knowledge, coping and support resources across all end points.

CONCLUSIONS

Exercise combined with NRT facilitates smoking cessation, improves functional exercise capacity, and delays weight gain in women smokers. We recommend that physicians and health care professionals recommend exercise and NRT together for highly motivated women interested in quitting smoking.

School fitness tests as predictors of adult health-related fitness

Relationships between adolescent physical fitness and adult health-related fitness were investigated. Forty-five subjects (20 males, 25 females) participated in physical fitness tests in 1976 and again in 2001. The adolescent physical fitness tests were distance running (2,000 m for boys or 1,500 m for girls), 50 m run, pull-ups (boys) or flexed arm hangs (girls), shuttle run, a 30-sec sit-up test, standing broad jump, hand grip-test, and sit-and-reach test. The adult health-related physical fitness index (APFI), stratified by sex, was formed by summing the z-scores of a bicycle ergometer test, sit-up test, hand-grip test, and sit-and-reach test. Height- and weight-adjusted correlations between adolescence and adulthood for exactly similar tests for men and women were, respectively, 0.74 (95% CI, 0.44-0.89) and 0.53 (95% CI, 0.17-0.76) in sit-and-reach tests, 0.41 (95% CI, -0.04 to 0.72) and 0.55 (95% CI, 0.20-0.78) in sit-up tests, and 0.53 (95% CI, 0.11-0.44) and 0.44 (95% CI, 0.05-0.71) in hand-grip tests. When all adolescent tests were put in regression analysis together with BMI in 2001, the significant explanatory factors for APFI were distance running ability and the sit-and-reach test for men and sit-up test, flexed arm hang, and BMI in 2001 for women.

Associations between self-estimated and measured physical fitness among 40-year-old men and women

The aim was to evaluate whether 40-year-old men and women are able to estimate their level of fitness compared with actual measured physical fitness. Twenty-nine men and 35 women first completed a questionnaire at home and then their physical fitness was measured at laboratory. The index of self-estimated physical fitness was calculated by summing up the scores of self-estimated endurance, strength, speed and flexibility. The index of self-estimated endurance was calculated by summing up the scores of self-estimated endurance and those of the self-estimated distance they could run, cycle, ski and walk. The index of measured physical fitness was calculated by summing up the z-scores of a submaximal bicycle ergometer test, ergojump tests (counter-movement jump and jumping in 15 s), a 30-s sit-up test, hand-grip tests and a sit-and-reach test. The correlation (Spearman) between the indices of self-estimated and measured physical fitness was 0.54 for both sexes, and that between self-estimated endurance and measured endurance was 0.53 for both sexes. Maximal oxygen uptake estimated based on submaximal ergometer test was higher among those with longer self-estimated distance of running, cycling, skiing and walking (P for linear trend <0.001). Our study shows that 40-year-old adults can estimate at group level their fitness according to different categories moderately well. They can also estimate at group level their endurance moderately well by estimating the distance they can run, cycle, ski or walk. However, in some individuals self-estimation of fitness is not in agreement with the results of fitness tests.

Relationship between physical fitness and lifestyle behaviour in healthy young men

BACKGROUND

There is substantial knowledge about the inverse association of physical fitness and CVD risk factors and CVD mortality. However, physical fitness per se might be influenced by lifestyle conditions such as physical training, smoking and drinking habits.

HYPOTHESIS

We evaluated the relationship between physical fitness, physical activity, endurance training, smoking and drinking habits and blood pressure, lipids and leukocytes as surrogate cardiovascular risk markers in a large-scale cross-sectional study of healthy young men.

STUDY DESIGN AND METHODS

A total of 6748 healthy young men were selected during their primary flight medical examination for military flying duties. Physical fitness was assessed by achieved physical working capacity at a heart rate of 170 beats per min (PWC170) during cycle ergometry. Parameters such as physical activity, endurance sports, smoking of cigarettes and drinking of alcoholic beverages were assessed by means of standardized questionnaires. Systolic and diastolic blood pressures were measured manually. Fasting cholesterol and triglycerides as well as white blood counts were obtained.

RESULTS

Physical activity itself was not related to significant differences in the tested variables, whereas good physical fitness showed a significant association with improved blood pressure and blood lipids (P<0.001) with no detectable threshold. This effect was independent of endurance training, smoking and drinking. Whereas drinking was associated with elevated systolic blood pressure, smoking was associated with markedly increased triglycerides as well as with elevated leukocytes.

CONCLUSION

Physical fitness is associated with improved blood pressure and blood lipids. This effect is independent of participating mainly in endurance or nonendurance sports, of physical activity per se, and it does not depend on smoking and drinking habits. Smoking itself revealed relevant higher inflammation independent of fitness.

The role of back muscle endurance, maximum force, balance and trunk rotation control regarding lifting capacity

Evaluation of lifting capacity is widely used as a reliable instrument in order to evaluate maximal and safe lifting capacity. This is of importance in regard to planning rehabilitation programs and determining working ability. The aim of this study was to investigate the influence of basic functions on the lifting capacity measured by the progressive isoinertial lifting evaluation (PILE) and the functional capacity evaluation (FCE) tests in a lower (floor to waist) and an upper (waist to shoulder) setting and compare the two test constructs. Seventy-four female subjects without acute low back pain underwent an examination of their lifting capacities and the following basic functions: (1) strength and endurance of trunk muscles, (2) cardiovascular endurance, (3) trunk mobility and (4) coordination ability. A linear regression model was used to predict lifting capacity by means of the above-mentioned basic functions, where the F statistics of the variables had to be significant at the 0.05 level to remain in the model. Maximal force in flexion showed significant influence on the lifting capacity in both the PILE and the FCE in the lower, as well as in the upper, lifting task. Furthermore, there was a significant influence of cardiovascular endurance on the lower PILE and also of endurance in trunk flexion on the lower FCE. Additional inclusion of individual factors (age, height, weight, body mass index) into the regression model showed a highly significant association between body height and all lifting tasks. The r (2) of the original model used was 0.19/0.18 in the lower/upper FCE and 0.35/0.26 in the lower/upper PILE. The model r (2) increased after inclusion of these individual factors to between 0.3 and 0.4. The fact that only a limited part of the variance in the lifting capacities can be explained by the basic functions analyzed in this study confirms the assumption that factors not related to the basic functions studied, such as lifting technique and motor control, may have a strong influence on lifting capacity. These results give evidence to suggest the inclusion of an evaluation of lifting capacity in clinical practice. Furthermore, they raise questions about the predictive value of strength and endurance tests in regard to lifting capacity and work ability.

An innovative program for changing health behaviours

Health-related behaviours affecting diet, weight control and physical activity are important for long-term cardiovascular health but behaviour change is difficult to initiate and even more difficult to maintain. We have developed a health promotion program, in which social support has a key role, to encourage a prudent diet, weight control and physical activity. Behaviour change is based on evaluating initial behaviour, weighing up costs and benefits, assessing barriers to change and goal-setting. We first evaluated the program in couples beginning to live together, a group chosen because of the risk of weight gain and decreased physical activity after marriage, readiness to change behaviour at that time in the life course and the opportunity to use partner's support in achieving behaviour change. In an initial short-term study with 39 couples, intake of fat and take-away foods decreased and consumption of fruit, vegetables and reduced fat foods increased. Physical activity increased and there was a 6% fall in blood cholesterol. Further evaluation in 137 couples included assessment after 12 months. A decrease in fat intake and increase in physical activity and fitness seen at the end of the program persisted 1 year later. Lower cholesterol and a trend to lower weight gain and lower blood pressure were also maintained after 12 months. We have modified the program aiming for weight loss, improved dietary habits and increased physical activity in overweight treated hypertensives, supported by their partners. Decreased intake of energy, total and saturated fat, and weight loss seen at the end of the 16 week program was significantly greater in the intervention group than with usual care. Blood pressure fell in the program group at the end of intervention and, in men, withdrawal of antihypertensive drugs was significantly associated with the intervention. Weight loss and a decrease in waist circumference were maintained in the program group up to 16 months after entering the study. This program has the potential for wider application in other at-risk groups.

Physical activity and sedentary behavior: a population-based study of barriers, enjoyment, and preference

The associations of physical activity and sedentary behavior with barriers, enjoyment, and preferences were examined in a population-based mail survey of 1,332 adults. Respondents reporting high enjoyment and preference for physical activity were more likely to report high levels of activity. Those reporting cost, the weather, and personal barriers to physical activity were less likely to be physically active. Preference for sedentary behavior was associated with the decreased likelihood of being physically active, and the weather a barrier to physical activity was associated with the increased likelihood of sedentary behavior. These constructs can be used to examine individual and environmental influences on physical activity and sedentary behavior in specific populations and could inform the development of targeted interventions.

Associations of physical activity with body weight and fat in men and women

OBJECTIVE

Increasing physical activity is strongly advocated as a key public health strategy for weight gain prevention. We investigated associations of leisure-time physical activity (LTPA) and occupational/domestic physical activity with body mass index (BMI) and a skinfold-derived index of body fat (sum of six skinfolds), among normal-weight and overweight men and women.

DESIGN

Analyses of cross-sectional self-report and measured anthropometric data.

SUBJECTS

A total of 1302 men and women, aged 18-78 y, who were part of a randomly selected sample and who agreed to participate in a physical health assessment.

MEASUREMENTS

Self-report measures of physical activity, measured height and weight, and a skinfold-derived index of body fatness.

RESULTS

Higher levels of LTPA were positively associated with the likelihood of being in the normal BMI and lower body fat range for women, but few or no associations were found for men. No associations were found between measures of occupational/domestic activity and BMI or body fat for men or women.

CONCLUSION

By using a skinfold sum as a more direct measure of adiposity, this study extends and confirms the previous research that has shown an association between BMI and LTPA. Our results suggest gender differences in the relationship of leisure-time physical activity with body fatness. These findings, in conjunction with a better understanding of the causes of such differences, will have important public health implications for the development and targeting of weight gain prevention strategies.

Cardiorespiratory fitness, physical activity level, and chronic pain: are men more affected than women?

OBJECTIVE

To evaluate the cardiorespiratory endurance (CRE) and physical activity level of patients with chronic pain compared with healthy subjects.

DESIGN AND SUBJECTS

Cross-sectional study, with a consecutive sample of 55 patients with chronic pain (20 men, 35 women). Comparison of CRE and physical activity indices obtained in patients with data available in the literature for age-matched healthy subjects.

SETTING

A multidisciplinary pain center in a city of more than 1,000,000 inhabitants.

OUTCOME MEASURES

A physical working capacity index (PWC65%/kg) and physical activity level scores and subscores obtained with two questionnaires (the Baecke and the Five-City Project questionnaires).

RESULTS

The physiological gender difference in CRE indices that characterizes healthy subjects was not observed in patients with chronic pain. When compared with values previously obtained in controls, male patients presented with a very significant 34% reduction in PWC65%/kg. The 17% reduction found in women hardly reached significance level. The Baecke total physical activity score was significantly higher in female than in male patients, a finding not observed in healthy controls. There was no significant difference between male and female patients in the Five-City Project total physical activity score expressed in kilocalories per day per kilogram (i.e., normalized for body weight), although data from the literature show that healthy men present with a significantly higher level of physical activity compared with healthy women.

CONCLUSIONS

Data on CRE and the physical activity level of patients with chronic pain obtained in this study show that chronic pain may have a greater impact on male than female patients. Sociocultural factors are probably at the origin of this phenomenon.

Fitness and perceived exertion in patients with fibromyalgia syndrome

OBJECTIVE

The aim of this study was to evaluate the cardiorespiratory fitness and perceived exertion of female patients with fibromyalgia syndrome (FMS) compared with that of healthy female subjects.

DESIGN AND SUBJECTS

This was designed as a cross-sectional case-control study, with a consecutive sample of 30 female patients with FMS and an age-matched control group of 67 healthy female subjects.

SETTING

This study was conducted at the multidisciplinary pain center of a university hospital in a city of more than 1 million inhabitants.

OUTCOME MEASURES

A cardiorespiratory fitness index (PWC65%/kg) and an original perceived exertion index (B65%) were obtained from the heart rates and perceived exertions scored on a 10-point Borg scale during a submaximal cycle ergometer test. Average indexes for the FMS patients and control subjects were compared.

RESULTS

The mean cardiorespiratory fitness index of the FMS patients was not significantly different from that of the controls. The mean perceived exertion index in the FMS patients was significantly greater than that of the controls, meaning that the FMS patients systematically reported higher ratings of perceived exertion during exercise.

CONCLUSIONS

Cardiorespiratory fitness, as expressed by a submaximal work capacity index, seems normal in female patients with FMS compared with age- and sex-matched healthy individuals. The fact that FMS patients overscore their perception of exertion may be due to a greater overlap of peripheral pain and perceived exertion perceptions during exercise. This observation should be noted when using perceived exertion scores to prescribe and monitor exercise in FMS patients.