Absolute versus relative intensity of physical activity in a dose-response context

Associations of Relative Intensity of Physical Activity With Incident Cardiovascular Events and All-Cause Mortality

BACKGROUND

The relative intensity of physical activity (PA) can be estimated as the percent of one's maximal effort required.

METHODS

We compared associations of relative and absolute intensity PA with incident major cardiovascular disease (CVD) and all-cause mortality in 5 633 women from the Objective Physical Activity and Cardiovascular Health Study (mean age 78.5 ± 6.7). Absolute intensity was measured by accelerometry. Relative intensity was estimated by dividing accelerometer-estimated metabolic equivalents (METs) by maximal MET capacity. Both were aggregated into mean daily hours of light intensity PA (LPA) and moderate-to-vigorous PA (MVPA). Cox proportional hazard models estimated hazard ratios (HRs) for 1-hour higher amounts of PA on outcomes.

RESULTS

During follow-up (median = 7.4 years), there were 748 incident CVD events and 1 312 deaths. Greater LPA and MVPA, on either scale, were associated with reduced risk of both outcomes. HRs for a 1-hour increment of absolute LPA were 0.88 (95% CI: 0.83-0.93) and 0.88 (95% CI: 0.84-0.92) for incident CVD and mortality, respectively. HRs for a 1-hour increment of absolute MPVA were 0.73 (95% CI: 0.61-0.87) and 0.55 (95% CI: 0.48-0.64) for the same outcomes. HRs for a 1-hour increment of relative LPA were 0.70 (95% CI: 0.59-0.84) and 0.78 (95% CI: 0.68-0.89) for incident CVD and mortality, respectively. HRs for a 1-hour increment of relative MPVA were 0.89 (95% CI: 0.83-0.96) and 0.82 (95% CI: 0.77-0.87) for the same outcomes. On the relative scale, LPA was more strongly, and inversely associated with both outcomes than relative MVPA. Absolute MVPA was more strongly inversely associated with the outcomes than relative MVPA.

CONCLUSIONS

Findings support the continued shift in the PA intensity paradigm toward recommendation of more movement, regardless of intensity. Relative LPA--a modifiable, more easily achieved behavioral target, particularly among ambulatory older adults--was associated with reduced risk of incident major CVD and death.

Comparison of the physical activity levels between shift workers and non-shift workers in a large-scale cross-sectional study in Iran

BACKGROUND

Shift work has been related to adverse health outcomes that can partially be attributed to physical inactivity. However, our knowledge of the influence of shift work on physical activity and sedentary behavior is inconclusive. Therefore, this study aimed to assess physical activity levels among shift and non-shift workers among a sample of Iranian adults.

METHODS

Baseline data of the Ravansar Non-Communicable Disease (RaNCD) cohort study were used. All participants of RaNCD except those excluded due to unemployment or considerable disability were included in the study. We evaluated participants' physical activity levels using the PERSIAN cohort questionnaire and examined its associations with being a shift worker.

RESULTS

A total of 4695 participants with a mean age of 46.1 (SD = 7.74) were included in the study. In total, 1108 (23.6%) participants were shift workers, 1420 (30.2%) had insufficient physical activity levels, and 4283 (91.2%) were male. The prevalence of physical inactivity was significantly lower among shift workers compared to non-shift workers (21% vs. 33.1%, p < 0.001). Multiple backward stepwise binary logistic regression tests indicated that being a shift worker was significantly associated with a lower chance of having insufficient physical activity levels (OR = 0.77, 95% CI = 0.65-0.92, p = 0.003).

CONCLUSIONS

The prevalence of insufficient physical activity was higher among non-shift workers than shift workers in our study. By providing the factors associated with insufficient physical activity among the workers in a region of Iran, the current study findings might help policymakers target groups at higher risk of physical activity in Iran and design interventions to improve physical activity, especially among non-shift workers.

Physical Activity as an Adjunct Treatment for People Living with HIV?

This review evaluates physical activity as a candidate for an adjunct treatment, in conjunction with antiretroviral therapy (ART), for people living with HIV (PLWH). Evidence is summarized that chronic, non-resolving inflammation (a principal feature of immune system dysfunction) and a dysfunctional state of the gut environment are key factors in HIV infection that persist despite treatment with ART. In addition, evidence is summarized that regular physical activity may restore normal function of both the immune system and the gut environment and may thereby ameliorate symptoms and non-resolving inflammation-associated comorbidities that burden PLWH. Physicians who care for PLWH could thus consider incorporating physical activity into treatment plans to complement ART. It is also discussed that different types of physical activity can have different effects on the gut environment and immune function, and that future research should establish more specific criteria for the design of exercise regimens tailored to PLWH.

Physical activity volume, intensity, and incident cardiovascular disease

AIMS

The interplay between physical activity (PA) volume and intensity is poorly understood in relation to cardiovascular disease (CVD) risk. This study aimed to investigate the role of PA intensity, over and above volume, in relation to incident CVD.

METHODS AND RESULTS

Data were from 88 412 UK Biobank middle-aged adults (58% women) without prevalent CVD who wore accelerometers on their dominant wrist for 7 days, from which we estimated total PA energy expenditure (PAEE) using population-specific validation. Cox proportional hazards regressions modelled associations between PAEE (kJ/kg/day) and PA intensity (%MVPA; the fraction of PAEE accumulated from moderate-to-vigorous-intensity PA) with incident CVD (ischaemic heart disease or cerebrovascular disease), adjusted for potential confounders. There were 4068 CVD events during 584 568 person-years of follow-up (median 6.8 years). Higher PAEE and higher %MVPA (adjusted for PAEE) were associated with lower rates of incident CVD. In interaction analyses, CVD rates were 14% (95% confidence interval: 5-23%) lower when MVPA accounted for 20% rather than 10% of 15 kJ/kg/d PAEE; equivalent to converting a 14 min stroll into a brisk 7 min walk. CVD rates did not differ significantly between values of PAEE when the %MVPA was fixed at 10%. However, the lowest CVD rates were observed for combinations of both higher PAEE and %MVPA.

CONCLUSION

Reductions in CVD risk may be achievable through higher PA volume and intensity, with the role of moderately intense PA appearing particularly important. This supports multiple approaches or strategies to PA participation, some of which may be more practical or appealing to different individuals.

Correlation of Walking Activity and Cardiac Hospitalizations in Coronary Patients for 1 Year Post Cardiac Rehabilitation: The More Steps, the Better!

Problem:

Reducing risk by improving fitness is one of the main objectives of cardiac rehabilitation (CR). To estimate how the number of steps/day post-CR affects coronary patients’ prognosis, we analyzed its correlation with the occurrence of death, hospitalizations, and heart complaints, and if and how other variables (ejection fraction (EF), gender, age) relate to those.

Methods:

One hundred eleven patients (male = 91, female = 20; average age ± standard deviation (SD): 61 ± 11 years) who had been in CR due to recent coronary revascularization or chronic coronary syndrome could be enrolled. Patients were advised to document their steps (daily), blood pressure (daily), weight (weekly) and occurrences of a cardiac event in a diary for 1 year post-CR. A Cox proportional hazard model was used to examine the influence of steps/day, EF, gender, and age until the occurrence of an event. Kaplan-Meier curves were generated to compare patients’ profiles.

Results:

Average steps/day of patients post-CR were 7333 (SD 4426). Increased walking activity reduced risk for cardiac hospitalization (constant steps/day: 5000 vs 7500, hazard rate (HR) reduction of 0.43; 10 000 vs 12 500, HR reduction of 0.20) and risk was higher in patients with an EF < 55% versus EF ⩾ 55% (HR increase of 2.88). Median follow-up time post-CR was 218 days. No patient died, 25 were hospitalized.

Discussion:

Monitoring the number of steps of coronary patients post CR could be valuable for estimating patients’ prognosis.

Longitudinal associations of absolute versus relative moderate-to-vigorous physical activity with brain microstructural decline in aging

Higher moderate-to-vigorous intensity (MVPA) may preserve brain structural integrity, but evidence is mostly cross-sectional and relies on absolute PA measures. We examined longitudinal associations of absolute MVPA using population-level activity count thresholds and relative MVPA using individual heart rate reserve (HRR) via Actiheart with subsequent changes in brain diffusion tensor imaging (DTI) over average of 3.8 years in 248 initially cognitively normal individuals (56-91 years). DTI markers included areas important for memory (temporal areas), executive (prefrontal cortex, superior longitudinal fasciculus), and motor function (precentral gyrus, putamen, caudate, body of corpus callosum). Associations of MVPA with changes in DTI markers were examined using linear mixed-effects models, adjusted for demographics and apolipoprotein e4 carrier status. Each additional 22 min of relative MVPA per day was significantly associated with less decline in fractional anisotropy of uncinate fasciculus and cingulum-hippocampal part and with less increase in mean diffusivity of entorhinal cortex and parahippocampal gyrus. Absolute MVPA was not associated with DTI changes. More time spent in relative MVPA by HRR may prevent brain microstructural decline in selected temporal areas.

Walking cadence (steps/min) and intensity in 61-85-year-old adults: the CADENCE-Adults study

BACKGROUND

Heuristic (i.e., evidence-based, rounded) cadences of ≥100 and ≥ 130 steps/min have consistently corresponded with absolutely-defined moderate (3 metabolic equivalents [METs]) and vigorous (6 METs) physical activity intensity, respectively, in adults 21-60 years of age. There is no consensus regarding similar thresholds in older adults.

PURPOSE

To provide heuristic cadence thresholds for 3, 4, 5, and 6 METs in 61-85-year-old adults.

METHODS

Ninety-eight community-dwelling ambulatory and ostensibly healthy older adults (age = 72.6 ± 6.9 years; 49% women) walked on a treadmill for a series of 5-min bouts (beginning at 0.5 mph with 0.5 mph increments) in this laboratory-based cross-sectional study until: 1) transitioning to running, 2) reaching ≥75% of their age-predicted maximum heart rate, or 3) reporting a Borg rating of perceived exertion > 13. Cadence was directly observed and hand-tallied. Intensity (oxygen uptake [VO2] mL/kg/min) was assessed with indirect calorimetry and converted to METs (1 MET = 3.5 mL/kg/min). Cadence thresholds were identified via segmented mixed effects model regression and using Receiver Operating Characteristic (ROC) curves. Final heuristic cadence thresholds represented an analytical compromise based on classification accuracy (sensitivity, specificity, positive and negative predictive value, and overall accuracy).

RESULTS

Cadences of 103.1 (95% Prediction Interval: 70.0-114.2), 116.4 (105.3-127.4), 129.6 (118.6-140.7), and 142.9 steps/min (131.8-148.4) were identified for 3, 4, 5, and 6 METs, respectively, based on the segmented regression. Comparable values based on ROC analysis were 100.3 (95% Confidence Intervals: 95.7-103.1), 111.5 (106.1-112.9), 116.0 (112.4-120.2), and 128.6 steps/min (128.3-136.4). Heuristic cadence thresholds of 100, 110, and 120 were associated with 3, 4, and 5 METs. Data to inform a threshold for ≥6 METs was limited, as only 6/98 (6.0%) participants achieved this intensity.

CONCLUSIONS

Consistent with previous data collected from 21-40 and 41-60-year-old adults, heuristic cadence thresholds of 100, 110, and 120 steps/min were associated with 3, 4, and 5 METs, respectively, in 61-85-year-old adults. Most older adults tested did not achieve the intensity of ≥6 METs; therefore, our data do not support establishing thresholds corresponding with this intensity level.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02650258 . Registered 24 December 2015.

Association of physical activity with blood pressure in African ancestry men

This study tested the association of objectively measured physical activity with blood pressure and hypertension in African Caribbean men, an understudied population segment known to be at high-risk for cardiovascular disease (CVD) which has low levels of high-exertion physical activity. Men (N = 310) were from the Tobago Health Study and aged 50-89 years. Systolic (SBP) and diastolic (DBP) blood pressures were measured using an automated device, and hypertension was defined as SBP ≥ 140 mmHg, DBP ≥ 90 mmHg, or current use of antihypertensive medication. Physical activity was measured using the SenseWear Pro armband (SWA) and consisted of daily time engaged in sedentary behavior (SB), light physical activity (LPA), and moderate to vigorous activity (MVPA), as well as daily step count. Multiple regression analyses using the isotemporal substitution framework were used to test for associations between activity and blood pressures. Models were adjusted in stages for SWA wear time, age, antihypertensive medication use, alcohol consumption, smoking, diabetes, CVD, family history of hypertension, salt intake, and adiposity. Replacement of SB with LPA was associated with lower SBP adjusted for wear time (β = -0.84, p < 0.05), but attenuated after adjustment for age. Replacement of SB with LPA was associated with lower DBP (β = -0.50) and lower odds of hypertension (OR = 0.88), adjusted for wear time and age (both p < 0.05). All model associations of replacement of SB with LPA were stronger when restricted to men not taking antihypertensive medications, regardless of their hypertension status. These results support the strategy of increasing light physical activity for blood pressure management in high-risk Afro-Caribbean men.

Machine Learning Approach for Fatigue Estimation in Sit-to-Stand Exercise

Physical exercise (PE) has become an essential tool for different rehabilitation programs. High-intensity exercises (HIEs) have been demonstrated to provide better results in general health conditions, compared with low and moderate-intensity exercises. In this context, monitoring of a patients' condition is essential to avoid extreme fatigue conditions, which may cause physical and physiological complications. Different methods have been proposed for fatigue estimation, such as: monitoring the subject's physiological parameters and subjective scales. However, there is still a need for practical procedures that provide an objective estimation, especially for HIEs. In this work, considering that the sit-to-stand (STS) exercise is one of the most implemented in physical rehabilitation, a computational model for estimating fatigue during this exercise is proposed. A study with 60 healthy volunteers was carried out to obtain a data set to develop and evaluate the proposed model. According to the literature, this model estimates three fatigue conditions (low, moderate, and high) by monitoring 32 STS kinematic features and the heart rate from a set of ambulatory sensors (Kinect and Zephyr sensors). Results show that a random forest model composed of 60 sub-classifiers presented an accuracy of 82.5% in the classification task. Moreover, results suggest that the movement of the upper body part is the most relevant feature for fatigue estimation. Movements of the lower body and the heart rate also contribute to essential information for identifying the fatigue condition. This work presents a promising tool for physical rehabilitation.

Development and Content Validity of the Physical Activity Questionnaire-Young Children (PAQ-YC) to Assess Physical Activity in Children between 5 and 7 Years

Childhood is a critical period in the development and consolidation of healthy habits, such as the practice of physical activity (PA). It is essential to have valid instruments to measure PA from an early age. The aim of this study was to design and evaluate the content validity of the Physical Activity Questionnaire-Young Children (PAQ-YC) to measure the PA level in children aged 5-7 years. The first version of the questionnaire was tested by a 2-round Delphi study. It was established as a consensus criterion that the relative interquartile range (RIR) and/or the coefficient of variation (CV) were ≤20%. The most significant discrepancies in the Delphi survey (n = 11-13) were observed for items about hours of Physical Education or similar activities at school (item 7: RIR = 20, CV = 38.73) and for items about participation in Physical Education (item 8: RIR = 25, CV = 15.45). The cognitive interviews (n = 5) confirmed the version agreed by the experts. The results show that the PAQ-YC presents adequate content validity in terms of relevance, comprehensiveness and comprehensibility.

Outdoor Walking Speeds of Apparently Healthy Adults: A Systematic Review and Meta-analysis

BACKGROUND

Walking outdoors can be used by many individuals to meet public health guidelines for moderate-to-vigorous-intensity physical activity. The speed at which adults walk may be a proxy for intensity. Traditional estimates of indoor walking speed are unlikely to reflect self-selected usual or other instructed paces of outdoor walking speed.

OBJECTIVE

To inform estimates of pace-based walking speed of apparently healthy adults in outdoor settings.

METHODS

We searched four electronic databases for articles published in English between January 1970 and March 2019. Studies that reported walking speed (m/s), cadence (steps/min), or intensity (mL/kg/min) of ambulatory, apparently healthy, and community-dwelling adults (> 18 years) were included. Walking speed categories were defined according to the description provided in each study. Meta-analysis was used to synthesise speed, cadence, and intensity data by slow, usual, medium, fast, and maximal pace (where reported).

RESULTS

Thirty-five studies, representing 14,015 participants (6808 women, 5135 men, and 2072 sex not specified), were identified. The mean (95% CI) walking speed for slow, usual, medium, fast, and maximal pace was 0.82 (0.77-0.86), 1.31 (1.27-1.35), 1.47 (1.44-1.49), 1.72 (1.64-1.81), and 1.62 (1.45-1.79) m/s, respectively. Mean cadence (95% CI) for usual and fast paces were 116.65 (114.95-118.35) and 126.75 (121.87-131.63) steps/min, respectively. The mean oxygen consumption (95% CI) for the usual and medium paces was 11.97 (11.69-12.25) and 13.34 (12.94-13.73) mL/kg/min, respectively.

CONCLUSION

These findings provide greater clarity with regard to how various indicators of enacted walking pace, speed, and intensity overlap and how each can be best communicated in the real-world setting to optimise health-related outcomes. Pace-based instructions can be used to support walking in outdoor settings within public health guidelines.

Associations of older adults' physical activity and bout-specific sedentary time with frailty status: Compositional analyses from the NEIGE study

AIM

To examine associations of intensity-specific physical activity and bout-specific sedentary time with frailty status among Japanese community-dwelling older adults, taking into account the interrelationships of these behaviors.

METHODS

Participants were 511 community-dwelling older adults. Physical activity and sedentary time were assessed using a tri-axial accelerometer. Frailty status (frail, pre-frail, or robust) was determined, based on the phenotypic model and used established criteria for Japanese older adults. Associations with frailty status of intensity-specific physical activity and bout-specific sedentary behavior (SB) time were examined using compositional data analysis, adjusted for potential confounders.

RESULTS

Participants included 13 (2.6%) who were frail, 234 (45.8%) pre-frail, and 264 (51.6%) who were robust. For the frail and pre-frail, the proportion of time spent in moderate-to-vigorous physical activity (MVPA) was less than for those who were robust. Frail older adults has larger proportion of time spent in prolonged (≥30 min/bouts) sedentary behavior (SB), and less in short-bout (<30 min/bout) SB, compared to the robust. No statistically-significant differences in the proportion of time spent in light-intensity physical activity was found across frailty levels.

CONCLUSION

Pre-frail and frail older adults spend proportionally less time in MVPA and more time in prolonged SB, compared with those who were robust. These findings need to be confirmed by evidence from larger and more-diverse study samples and by evidence from prospective studies, in order to better understand whether or not avoiding prolonged periods of sitting could be a potential strategy for preventing frailty among community-dwelling older adults.

Walking Volume and Speed Are Inversely Associated With Incidence of Treated Hypertension in Postmenopausal Women

Few studies have evaluated hypertension incidence in relation to walking, which is a common physical activity among adults. We examined the association between walking and hypertension incidence in 83 435 postmenopausal women who at baseline were aged 50 to 79 years, without known hypertension, heart failure, coronary heart disease, or stroke, and reported the ability to walk at least one block without assistance. Walking volume (metabolic equivalent hours per week) and speed (miles per hour) were assessed by questionnaire. Incident physician-diagnosed hypertension treated with medication was ascertained through annual questionnaires. During a mean 11-year follow-up, 38 230 hypertension cases were identified. After adjustment for covariates including nonwalking activities, a significant inverse association with hypertension was observed across categories of baseline walking volume (0 [referent], >0-3.5, 3.6-7.5, and >7.5 metabolic equivalent hours per week), hazard ratio: 1.00 (referent), 0.98, 0.95, 0.89; trend P<0.001. Faster walking speeds (<2, 2-3, 3-4, and >4 miles per hour) also were associated with lower hypertension risk, hazard ratio: 1.00 (referent), 1.07, 0.95, 0.86, 0.79; trend P<0.001. Further adjustment for walking duration (h/wk) had little impact on the association for walking speed (hazard ratio: 1.00 [referent], 1.08, 0.96, 0.86, 0.77; trend P<0.001). Significant inverse associations for walking volume and speed persisted after additional control for baseline blood pressure. Results for time-varying walking were comparable to those for baseline exposures. This study showed that walking at guideline-recommended volumes (>7.5 metabolic equivalent hours per week) and at faster speeds (≥2 miles per hour) is associated with lower hypertension risk in postmenopausal women. Walking should be encouraged as part of hypertension prevention in older adults.

Wearable-device-measured physical activity and future health risk

Use of wearable devices that monitor physical activity is projected to increase more than fivefold per half-decade1. We investigated how device-based physical activity energy expenditure (PAEE) and different intensity profiles were associated with all-cause mortality. We used a network harmonization approach to map dominant-wrist acceleration to PAEE in 96,476 UK Biobank participants (mean age 62 years, 56% female). We also calculated the fraction of PAEE accumulated from moderate-to-vigorous-intensity physical activity (MVPA). Over the median 3.1-year follow-up period (302,526 person-years), 732 deaths were recorded. Higher PAEE was associated with a lower hazard of all-cause mortality for a constant fraction of MVPA (for example, 21% (95% confidence interval 4-35%) lower hazard for 20 versus 15 kJ kg-1 d-1 PAEE with 10% from MVPA). Similarly, a higher MVPA fraction was associated with a lower hazard when PAEE remained constant (for example, 30% (8-47%) lower hazard when 20% versus 10% of a fixed 15 kJ kg-1 d-1 PAEE volume was from MVPA). Our results show that higher volumes of PAEE are associated with reduced mortality rates, and achieving the same volume through higher-intensity activity is associated with greater reductions than through lower-intensity activity. The linkage of device-measured activity to energy expenditure creates a framework for using wearables for personalized prevention.

Physical activity, sedentary time and sleep and associations with mood states, shift work disorder and absenteeism among nurses: an analysis of the cross-sectional Champlain Nurses' Study

BACKGROUND

Research has suggested ideal combinations of sleep, physical activity (PA) and sedentary time (ST) (i.e., optimal sleep/high PA/low ST) are associated with better overall health. Previous research has shown nurses spend more than half their day sedentary, do not generally meet PA guidelines and have difficulty obtaining adequate sleep. There has been no known work to examine how combinations of sleep, PA and ST relate to the work performance and mental health of nurses. Our objective was to assess the associations of sleep, PA and ST with absenteeism, mood states and shift work disorder (SWD) in a sample of Canadian nurses.

METHODS

A total of 342 nurses from the Champlain Nurses' Study (mean age ± SD = 43 ± 12 years, 94% women) wore an ActiGraph GT3X accelerometer for ≥ 4 days for ≥ 10 h/day to derive time spent in moderate-to-vigorous intensity physical activity (MVPA) and ST and reported sleep time for ≥ 4 days using daily activity logs. Behavioural patterns were categorized into four groups for comparison based on opposing combinations of sleep, MVPA and ST (e.g., optimal sleep/high MVPA/low ST vs. non-optimal sleep/low MVPA/high ST). Self-reported absenteeism, mood states and SWD as measured by the Profile of Mood States (POMS) and Shift Work Disorder Screening questionnaires, respectively, were compared across combinations of high versus low MVPA and ST, and optimal vs. non-optimal sleep.

RESULTS

Nurses spent an average of 444 ± 11 min/day sedentary, 14 ± 15 min/day in bouts ≥ 10 minutes of MVPA (23% met PA guidelines) and reported an average of 8 h and 39 min ± 1 h 6 min of sleep/24-h. Significant associations between behaviour groups and the POMS score and its vigor subscale, as well as SWD were observed, however, none were observed for absenteeism. The healthiest behaviour group had a significantly lower mood disturbance compared to 2/3 unhealthy behaviours and greater vigor compared to 2/3 and 3/3 unhealthy behaviours. SWD trended toward being higher amongst the group with 2/3 unhealthy behaviours. Meeting PA guidelines was associated with significantly lower total mood disturbance versus not meeting guidelines (median [IQR] = 0.4 [4.5] vs. 1.3 [4.4], Z =  - 2.294, df = 1, p = 0.022), as well as lower anger, higher vigor and lower fatigue. Low ST was associated with lower POMS total mood disturbance scores versus higher ST (0.6 [4.4] vs. 1.4 [4.3], Z = 2.028, df = 1, p = 0.043), as well as higher vigor and lower fatigue.

CONCLUSIONS

In this sample of hospital nurses, the combined effects of sleep, PA and ST are associated with total mood disturbance and SWD. Achieving the recommended levels in all three behaviours may be beneficial in decreasing total mood disturbance and minimizing the effects of SWD. Future work is needed to address the low PA and high ST levels of nurses and to better understand how these behaviours can be improved to optimize the mental health of the health workforce.

Effect of physical activity on suicidal ideation differs by gender and activity level

BACKGROUND

Suicide is a critical complication of psychiatric disorders. Physical activity has a positive effect on mental health; however, its effects on suicidal ideation have received little attention compared to other psychiatric symptoms.

METHODS

Data were obtained from the Korea National Health and Nutrition Examination Survey 2014. Suicidal ideation was measured by the ninth item of the Patient Health Questionnaire-9. Physical activity was measured by the International Physical Activity Questionnaire (IPAQ) and categorized into three groups by activity level. Multiple logistic regression analysis was performed for the entire sample, men, and women. The following three models were used: Model 1 (adjusted for sociodemographic and health-related variables), Model 2 (additionally adjusted for subjective body image), and Model 3 (additionally adjusted for diagnosed depression).

RESULTS

Compared to the low IPAQ group, the moderate IPAQ group was significantly associated with decreased suicidal ideation in Model 3 for the entire sample (OR, 0.733; 95% CI, 0.538-0.999) and in all models for women. However, the high IPAQ group showed no significant association. None of the IPAQ groups showed significant associations in men.

LIMITATIONS

This is a cross-sectional study. Therefore, the direction of causality cannot be determined. This study also investigated suicidal ideation over the past two weeks, which may be inconsistent with studies conducted over the past year.

CONCLUSIONS

The beneficial relationship between physical activity and suicidal ideation is weaker in men and individuals with high activity levels. Detailed guidelines on physical activity according to gender and activity level are recommended.

Comparison of association between physical activity and resting metabolic rate in young and middle-aged Korean adults

PURPOSE

The purpose of this study was to comparatively investigate the correlation among body composition, resting metabolic rate (RMR), and physical activity (PA) between young and middle-aged Korean adults.

METHODS

A total of 53 [male n=23, female n=30] subjects were included in this study, among whom 34 subjects were healthy young adults [male n=18, female n=16] and 19 were middle-aged adults [male n=5, female n=14]. The body composition and RMR of all the participants were measured after overnight fasting (≥8 h). The Korean version of the WHO Global Physical Activity Questionnaire (GPAQ) was used to assess physical activity.

RESULTS

Body composition was not significantly different between young adults and middle-aged adults. Whole-body bone mineral density and bone mineral contents (BMC) were significantly lower in middle-aged adults than in young adults. Total blood cholesterol (TC) and blood glucose levels were significantly higher in middle-aged adults (TC; 195.21 ± 43.34, glucose; 103.57 ± 12.61 mg/dL) than in young adults. RMR was significantly lower in middle-aged adults (1619.57 ± 290.28 kcal/day) than in young adults (1894.37 ± 405.00 kcal/day). In middle-aged adults physical activity (PA). PA (METs, min, EE) was inversely correlated with fat mass (FM, kg, and %) and blood triglyceride (TG) level in young adults. In middle-aged adults, PA showed a significant positive correlation with lean body mass (LBM), FM (%), and RMR. Furthermore, PA EE showed significant interrelatedness with BMC among middle-aged adults.

CONCLUSION

These results demonstrated that high PA levels enable LBM and RMR maintenance in middle-aged adults. Furthermore, in young adults, more PA is required to induce change in body composition.

Using Heart Rate and Accelerometry to Define Quantity and Intensity of Physical Activity in Older Adults

Background

Physical activity (PA) prevents disease and promotes longevity; yet, few older adults meet the recommended daily guidelines. Wearable PA and heart rate monitors provide the opportunity to define age-related differences in the absolute and relative intensity of daily activities, and provide insight into the underlying factors influencing PA in older adults.

Methods

Participants in the Baltimore Longitudinal Study of Aging (n = 440, 52% male, aged 31 to 88 years) completed a clinical assessment and wore an Actiheart monitor in the free-living environment. The association between age and minutes per day in sedentary, light, moderate, and vigorous PA was assessed using relative intensity, as defined by heart rate reserve, and absolute intensity using activity count thresholds.

Results

In cross-sectional analyses, time spent in sedentary and light activities as defined by relative intensity did not differ across age (p > 0.05), whereas time spent in moderate and vigorous relative PA was higher for each 1 year increase in age (p < .01). Using absolute intensity PA thresholds, older adults registered fewer activity counts per day with more sedentary time and lesser amounts of light, moderate, and vigorous PA (p < .05). Persons with higher relative and lower absolute PA intensity had poorer functional performance and higher subclinical disease indicators.

Conclusions

These findings suggest that time spent in moderate or higher intensity activities may not be lower with age after considering changes in physiology, functional ability, and subclinical disease burden and highlight the need for more age- and ability-specific PA research to inform future interventions and public health guidelines.

Preditores e condições de saúde associados à prática de atividade física moderada e vigorosa em adultos e idosos no sul do Brasil

RESUMO: Introdução: A atividade física (AF) regular promove diversos benefícios à saúde. O objetivo deste estudo foi analisar os preditores da AF moderada (AFM) e da AF vigorosa (AFV), separadamente, bem como alguns desfechos de saúde relacionados a cada intensidade. Método: Estudo transversal, de base populacional, com adultos e idosos da zona urbana do município de Rio Grande (RS), Brasil. A AF foi coletada por meio da seção de lazer do Questionário Internacional de Atividade Física (IPAQ). Os pontos de corte utilizados para AFM e AFV foram, respectivamente, 150min./sem. e 75min./sem. As condições de saúde analisadas foram: obesidade, estresse, hipertensão, diabetes, depressão e autopercepção da saúde. Resultados: Participaram 1.290indivíduos, com idade média de 46,0 anos (DP = 17,3). Foram classificados como ativos para AFM e AFV 14,3% (IC95% 11,7 - 16,8) e 14,6% (IC95% 12,1 - 17,1), respectivamente. Sexo masculino, maior escolaridade, percepção mais favorável do bairro e mais horas diárias de sono foram associados a maiores prevalências de AFM. Sexo masculino, idade de 20 a 39 anos, cor de pele branca, ausência de tabagismo, maior escolaridade e maior índice de bens foram associados a maiores prevalências de AFV. Com relação aos desfechos de saúde, a AFM conferiu proteção para estresse, enquanto a AFV constituiu fator protetor para obesidade, hipertensão e diabetes. Conclusões: Verificou-se que tanto os preditores quanto os desfechos de saúde diferiram conforme a intensidade da AF.

Are There Limitations to Exercise Benefits in Peripheral Arterial Disease?

Substantial evidence exists indicating that inactivity contributes to the progression of chronic disease, and conversely, that regular physical activity can both prevent the onset of disease as well as delay the progression of existing disease. To that end "exercise as medicine" has been advocated in the broad context as general medical care, but also in the specific context as a therapeutic, to be considered in much the same way as other drugs. As there are non-responders to many medications, there also are non-responders to exercise; individual who participate but do not demonstrate appreciable improvement/benefit. In some settings, the stress induced by exercise may aggravate an underlying condition, rather than attenuate chronic disease. As personalized medicine evolves with ready access to genetic information, so too will the incorporation of exercise in the context of those individual genetics. The focus of this brief review is to distinguish between the inherent capacity to perform, as compared to adaptive response to active exercise training in relation to cardiovascular health and peripheral arterial disease.

Establishing cut-points for physical activity classification using triaxial accelerometer in middle-aged recreational marathoners

The purpose of this study was to establish GENEA (Gravity Estimator of Normal Everyday Activity) cut-points for discriminating between six relative-intensity activity levels in middle-aged recreational marathoners. Nighty-eight (83 males and 15 females) recreational marathoners, aged 30–45 years, completed a cardiopulmonary exercise test running on a treadmill while wearing a GENEA accelerometer on their non-dominant wrist. The breath-by-breath V̇O₂ data was also collected for criterion measure of physical activity categories (sedentary, light, moderate, vigorous, very vigorous and extremely vigorous). GENEA cut-points for physical activity classification was performed via Receiver Operating Characteristic (ROC) analysis. Spearman’s correlation test was applied to determine the relationship between estimated and measured intensity classifications. Statistical analysis were done for all individuals, and separating samples by sex. The GENEA cut-points established were able to distinguish between all six-relative intensity levels with an excellent classification accuracy (area under the ROC curve (AUC) values between 0.886 and 0.973) for all samples. When samples were separated by sex, AUC values were 0.881–0.973 and 0.924–0.968 for males and females, respectively. The total variance in energy expenditure explained by GENEA accelerometer data was 78.50% for all samples, 78.14% for males, and 83.17% for females. In conclusion, the wrist-worn GENEA accelerometer presents a high capacity of classifying the intensity of physical activity in middle-aged recreational marathoners when examining all samples together, as well as when sample set was separated by sex. This study suggests that the triaxial GENEA accelerometers (worn on the non-dominant wrist) can be used to predict energy expenditure for running activities.

Metabolic equivalent of task (METs) thresholds as an indicator of physical activity intensity

The purpose of the study was to identify and compare validity parameters of different absolute intensity thresholds in METs, using relative intensity classification as criterion measure. Convenience sampling was used to recruit total of 112 adults. The participants carried out an incremental maximal cycle ergometer test and asked to perform nine free-living activities. The oxygen uptake was measured by a VO2000® gas analyser throughout the tests. The intensity thresholds were identified using Receiver Operator Characteristic (ROC) curve analysis, having relative intensity categories as criterion measure. A total of 103 participants attended the two visits. Among 54 men and 49 women, the mean (± SD) ages were 36.1 (± 11.1) and 33.9 (± 10.6) years, respectively. The intensity thresholds identified were 4.9 METs for moderate and 6.8 METs for vigorous physical activity. In conclusion, the physical activity thresholds, generated according to the entire sample, were higher and presented improved specificity when compared to thresholds currently recommended. Moreover, these parameters presented relatively high accuracy, even when applied to specific groups such as sex, age, nutritional status and physical fitness.

Experimental effects of acute exercise duration and exercise recovery on mood state

OBJECTIVE

Accumulating evidence suggests that, in addition to various psychosocial parameters, affective responses to exercise play an important role in subserving future exercise behavior. This study comprehensively evaluated whether acute exercise duration and recovery period influenced the relationship between moderate-intensity walking exercise and mood profile.

METHOD

We employed a randomized controlled cross-over trial. Participants completed two laboratory visits, separated by one-week. One of the visits involved a mood profile assessment with no exercise, while the other visit involved a mood profile assessment after an acute bout of exercise. Participants (N = 352; 22 per group; young [M_age = 21 yrs] healthy adults) were randomized into one of 16 experimental groups: 10, 20, 30, 45 or 60min bout of exercise coupled with either a 5, 15 or 30min recovery period. The exercise bout was of moderate-intensity (40-59% of HRR). Mood profile was assessed from the POMS survey, considering subscales of depression, anger and hostility.

RESULTS

For all three mood profile parameters, there was no evidence of a group x time interaction effect. However, the main effect for time was statistically significant for each mood parameter. These significant results demonstrate that, generally, exercise had a favorable effect on each of the mood profile, regardless of exercise duration and recovery period. In addition to the significant main effects for time, we also observed a significant main effect for group for the mood parameter hostility. With the exception of the group 13 (60min of exercise with 5min recovery) and the 3 groups that employed a 10-min bout of exercise (groups 1-3), all other experimental groups had a lower (better) hostility score after the exercise visit.

CONCLUSIONS

Generally, exercise had a favorable effect on various mood profiles, regardless of exercise duration (between 10 and 60min) and recovery period (between 5 and 30min).

Absolute and relative accelerometer thresholds for determining the association between physical activity and metabolic syndrome in the older adults: The Generation-100 study

BACKGROUND

When assessing population adherence to physical activity (PA) recommendation using accelerometers, absolute intensity threshold definition is applied despite having limited validity in those with low cardiorespiratory fitness (CRF), who are unable to reach them (e.g older adults). Thus, PA thresholds relative to CRF may be an alternative approach. We compared the proportion of the older adults meeting the PA recommendation when PA is assessed using absolute versus sex-and-CRF-adjusted (relative) accelerometer thresholds and determined the association between relative versus absolute moderate PA (MPA), vigorous PA (VPA) and moderate-to-vigorous PA (MVPA) and metabolic syndrome (MetS).

METHODS

Cross-sectional study of 509 men and 567 women aged 70-77. Accelerometer assessed MPA, VPA and MVPA were analyzed using absolute and relative thresholds. Meeting the PA-recommendation was defined as amounting ≥150 min/week in MPA/MVPA or 75 min/week in VPA, respectively. CRF was directly measured as peak oxygen uptake (VO_2peak). MetS was defined as 3 or more of the following: elevated waist circumference, fasting glucose, hypertension, triglycerides, decreased HDL-cholesterol or diabetes, dyslipidemia or hypertension medication.

RESULTS

Higher proportion of the population met the recommendation when PA was assessed with relative compared to absolute thresholds: VPA (72.4% vs. 1.7%) and MVPA (75.2% vs. 33.8%). Logistic regression analysis revealed that men and women not meeting the relative-MVPA or VPA recommendation had higher likelihood of MetS (Men: MVPA OR: 1.59, 95% CI: 1.08-2.33.

VPA OR

1.81, 95%CI: 1.23-2.67 and Women: MVPA OR: 2.12, 95% CI: 1.36-3.31; VPA OR: 1.95, 95% CI: 1.29-2.95), compared to men and women meeting the relative MVPA or VPA recommendation. There was no significant association between MetS and absolute MVPA, MPA or VPA recommendations in the fully adjusted model.

CONCLUSIONS

The association between meeting/not meeting the PA recommendation and MetS differed with method. Not meeting relative MVPA and VPA recommendation was associated with significantly higher likelihood for presence of MetS. Since relative intensity is part of the current PA recommendation, it should be considered when assessing population PA and associated health risks in the older adults.

TRIAL REGISTRATION

Clinical Trial Registration: NCT01931111 (Date of trial registration: July 19, 2013).

Behavioral determinants of physical activity across the life course: a "DEterminants of DIet and Physical ACtivity" (DEDIPAC) umbrella systematic literature review

Background

Low levels of physical activity (PA) are a global concern and increasing PA engagement is becoming a priority in current public health policies. Despite the large number of studies and reviews available, the evidence regarding the behavioral determinants of PA is still inconclusive. Thus, the aim of this umbrella systematic literature review (SLR) was to summarize the evidence on the behavioral determinants of PA across the life course.

Methods

A systematic online search was conducted on MEDLINE, ISI Web of Science, Scopus, and SPORTDiscus databases. The search was limited to studies published in English from January, 2004 to April, 2016. SLRs and meta-analyses (MAs) of observational studies that investigated the behavioral determinants of PA were considered eligible. The extracted data were assessed based on the importance of the determinants, the strength of evidence, and the methodological quality. The full protocol is available from PROSPERO (PROSPERO 2014:CRD42015010616).

Results

Seventeen reviews on 35 behavioral determinants of PA were eligible for this umbrella SLR. Regardless of age, the most investigated determinants were those related with ‘screen use’ and ‘smoking’. For youth, probable positive evidence emerged for ‘previous PA’ and ‘independent mobility and active transport’ among children and adolescents. For the adult population, ‘transition to university’ and ‘pregnancy/having a child’ showed probable negative associations.

Conclusions

Although the majority of the evidence was limited and most of the determinants were not associated with PA, this umbrella SLR provided a comprehensive overview of the associations between behavioral determinants and PA. Youth should be physically active in the early years and increase active transportation to/from school, independent mobility, and ‘free-range activities’ without adult supervision, whilst adult PA behaviors are mostly influenced by the life events. Finally, more research is needed that incorporates prospective study designs, standardized definitions of PA, objective measurement methods of PA assessment, and the use of interactionist and mediational approaches for the evaluation of different behavioral determinants influencing PA behaviors.

Cardiovascular response to bouts of exercise with blood flow restriction

[Purpose] Occlusion training with low-intensity resistance exercises and blood flow restriction increases muscle cross-sectional area and strength. This form of training is used in rehabilitation; therefore, the aim of this study was to examine the effect of one occlusion training session on the cardiovascular response to bouts of exercise. [Subjects and Methods] Two groups took part: a control group without blood flow restriction and an experimental group with blood flow restriction. A single training session was used with the exercise intensity set at 40% of the one repetition maximum. Maximum voluntary contraction, arterial blood pressure, and electrocardiogram measurements were performed. [Results] Heart rate was slightly higher in the control group. The performed training had no effect on diastolic blood pressure in either group, however, a tendency for a small systolic blood pressure increase was observed during the session in the experimental group. JT interval changes did not reveal significant differences between groups. There were no significant changes in ST-segment depression during the exercise or at rest. A lower tendency for JT/RR increases was observed during the repeated exercise tasks with partial blood flow restriction. [Conclusion] Low intensity exercises carried out with a partial blood flow restriction do not result in significant overload of cardiac function.

Leisure-Time Physical Activity and Sedentary Behavior and Their Cross-Sectional Associations with Excessive Daytime Sleepiness in the French SU.VI.MAX-2 Study

BACKGROUND

The potential benefit of physical activity in terms of decreasing excessive daytime sleepiness (EDS) prevalence is unclear, especially in aging adults.

PURPOSE

We aimed to elucidate the associations among physical activity, sedentariness, and EDS in middle-aged and older adults.

METHODS

We conducted a cross-sectional analysis using data from a subsample of participants in the SU.VI.MAX-2 observational study (2007-2009; N = 4179; mean age = 61.9 years). EDS was defined as a score >10 on the Epworth Sleepiness Scale. Leisure-time physical activity and different types of sedentary behavior were assessed with the Modifiable Activity Questionnaire. The associations were examined with multivariable logistic regression models.

RESULTS

In the adjusted multivariable model, total leisure-time physical activity (modeled in quartiles, Q) was significantly, inversely associated with EDS (odds ratios (OR)Q4 vs Q1 = 0.70, 95 % confidence interval (CI) = 0.54-0.89). The association persisted in analyses restricted to individuals not taking sleep medication (ORQ4 vs Q1 = 0.72, 95 % CI = 0.54-0.95). In turn, time spent watching television and time spent reading appeared protective against EDS (ORQ4 vs Q1 = 0.73, 95 % CI = 0.57-0.94; ORQ4 vs Q1 = 0.76, 95 % CI = 0.60-0.97, respectively), whereas time spent on a computer appeared to confer an increased risk for EDS (ORQ4 vs Q1 = 1.30, 95 % CI = 1.05-1.62). When physical activity and sedentariness were modeled jointly, using WHO recommendation-based cutoffs for high/low levels, no significant associations were observed in the fully adjusted models.

CONCLUSIONS

The findings reinforce public health recommendations promoting behavior modification and specifically moderate-intensity exercise in middle-aged and older adults. The association of high physical activity/low sedentariness with EDS, which was not supported by the data, merits further investigation before firm conclusions could be drawn.

Perceived exertion of physical activity: Negative association with self-rated fitness

Introduction: In epidemiological studies information on physical activity is often obtained by self-report questionnaires, assessing the type of activities performed, the absolute metabolic demand (metabolic equivalents), and the duration and frequency of the activities. As health benefits from physical activity are coupled to the relative intensity of the physical effort, we wanted to relate perceived exertion to self-reported fitness. Aim: To use a questionnaire for obtaining information on perceived exertion of physical activity in a population sample and to evaluate whether perceived exertion is associated with self-reported fitness. Methods: A total of 42 specific physical activities were included in a perceived exertion questionnaire that was sent by mail to 2,543 randomly selected men and women between 19 and 60 years of age. The participants were asked to rate activities by degree of perceived exertion on an 11-point box-scale. General linear regression analyses were undertaken with perceived exertion of the specific physical activities as outcome variables and age and self-rated fitness as determinants. Results: The response rate was 61.7% (n=1,568) and 54.3% of the respondents were women. In men and women both, the perceived exertion of 40 out of 42 specific physical activities of low, moderate, and high absolute intensity was negatively associated with self-rated fitness level. Conclusion: Perceived exertion is significantly associated with self-rated fitness level in both genders after adjustment for age. Self-rated fitness level seems to determine perception of exertion in leisure time, occupation, household, and transportation activities, whether of low, moderate, or high absolute intensity.

Relations of Body Concerns and Exercise Behavior: A Meta-Analysis

Numerous studies have examined the relations between body concerns and exercise. This meta-analysis is based on 35 studies with exercise programs influencing body concerns. There was an overall effect of .45, suggesting that exercise positively affects body concerns. Moderator variables, such as sex, type of exercise, and length of intervention were examined and discussed. Generally, there were no sex differences in effects of exercise on body concerns, but anaerobic exercise such as weight training generated a stronger effect ( d=.64) than aerobic-type exercises such as jogging ( d=.40).

Cadence Feedback With ECE PEDO to Monitor Physical Activity Intensity: A Pilot Study

The purpose of this study was to examine the monitoring capabilities of the equipment for clever exercise pedometer (ECE PEDO) that provides audible feedback when the person exceeds the upper and lower limits of the target step numbers per minute and to compare step counts with Yamax SW-200 (YX200) as the criterion pedometer.A total of 30 adult volunteers (15 males and 15 females) were classified as normal weight (n = 10), overweight (n = 10), and obese (n = 10). After the submaximal exercise test on a treadmill, the moderate intensity for walking was determined by using YX200 pedometer and then the number of steps taken in a minute was measured. Lower and upper limits of steps per minute (cadence) were recorded in ECE PEDO providing audible feedback when the person's walking speed gets out of the limits. Volunteers walked for 30 minutes in the individual step count range by attaching the ECE PEDO and YX200 pedometer on both sides of the waist belt in the same session. Step counts of the volunteers were recorded. Wilcoxon, Spearman correlation, and Bland-Altman analyses were performed to show the relationship and agreement between the results of 2 devices.Subjects took an average of 3511 ± 426 and 3493 ± 399 steps during 30 minutes with ECE PEDO and criterion pedometer, respectively. About 3500 steps taken by ECE PEDO reflected that this pedometer has capability of identifying steps per minute to meet moderate intensity of physical activity. There was a strong correlation between step counts of both devices (P < 0.001, r = 0.96). Correlations across all three BMI categories and both sex remained consistently high ranging from 0.92 to 0.95. There was a high level of agreement between the ECE PEDO and YX200 pedometer in the Bland-Altman analysis.Although both devices showed a strong similarity in counting steps, the ECE PEDO provides monitoring of intensity such that a person can walk in a specified time with a desired speed.

Validity of Cooper's 12-minute run test for estimation of maximum oxygen uptake in male university students

The present study was conducted to validate the applicability of Cooper's 12-minute run test (CRT) for predicting VO₂max in male university students of Kolkata, India, to bypass the exhaustive and complicated protocol of direct estimation of VO₂max. Eighty-eight sedentary male university students recruited by simple random sampling from the University of Calcutta, Kolkata, were randomly assigned to the study group (N = 58) and the confirmatory group (N = 30). VO₂max of each participant was determined by the direct procedure and the indirect CRT method. The mean value of predicted VO₂max (PVO₂max) (42.8±4.0 ml · kg⁻¹ · min⁻¹ with a range of 33.7–50.9) showed a significant difference with VO₂max (39.8±4.0 ml · kg⁻¹ · min⁻¹ with a range of 33.5–47.7) in the study group. Limits of agreement between PVO₂max and VO₂max were large enough (0.10 to 5.94 ml · kg⁻¹ · min⁻¹) with poor confidence intervals indicating inapplicability of the current protocol of CRT in the studied population. The prediction norm [Y = 21.01X – 11.04 (SEE = 0.193 ml · kg⁻¹ · min⁻¹)] was computed from the significant correlation (r = 0.93, P < 0.001) between distance covered in CRT and VO₂max. Application of this norm in the confirmatory group revealed an insignificant difference between PVO₂max and VO₂max. The modified equation is recommended for application of CRT as a valid method to evaluate the cardiorespiratory fitness in terms of VO₂max in sedentary male Indian youth.

Non-exercise physical activity and survival: English longitudinal study of ageing

BACKGROUND

The activity patterns of older adults include more light/mild-intensity or "non-exercise" activity and less moderate- to vigorous-intensity activity. The health benefits of this type of activity pattern remain unclear.

PURPOSE

To examine dose-response associations between physical activity and survival using time-varying analysis to understand the importance of "non-exercise" activity for survival in older adults.

METHODS

Participants (N=10,426) were drawn from The English Longitudinal Study of Ageing, a representative sample of men and women aged ≥50 years living in England. Participant data were linked with death records from the National Health Service registries from 2002 to 2011. Analyses were conducted in 2013. Cox proportional hazards models were used to estimate the risk of death according to time-varying estimates of physical activity.

RESULTS

Over an average follow-up of 7.8 years (median follow-up, 8.5 years), there were 1,896 deaths. In models adjusted for comorbidities, psychosocial factors, smoking, and obesity, there was a dose-response association between time-varying physical activity and mortality, with the greatest survival benefit in vigorously active participants. However, participating in mild ("non-exercise")-intensity physical activity was also associated with a lower risk of all-cause mortality (hazard ratio [HR]=0.76, 95% CI=0.69, 0.83); cardiovascular mortality (HR=0.74, 95% CI=0.64, 0.85); and death by other causes (HR=0.67, 95% CI=0.58, 0.78). Time-varying models produced stronger, more robust estimates than models using a single measurement of physical activity at baseline.

CONCLUSIONS

Older adults gain health benefits from participating in regular "non-exercise" physical activity, although the greatest benefits are observed for more vigorous activity.

Dose-response association of physical activity with acute myocardial infarction: do amount and intensity matter?

OBJECTIVE

The aims of this study were to analyze the dose-response association between leisure time physical activity (PA) practice and myocardial infarction (MI), considering not only the total amount but also the amount of PA at different levels of intensity, and to determine whether these associations were modified by age.

METHOD

In a population-based age- and sex-matched case-control study, all first acute MI patients aged 25 to 74 years were prospectively registered in four Spanish hospitals between 2002 and 2004. Controls were randomly selected from population-based samples recruited during the same period of time. The Minnesota PA questionnaire was administered to assess total energy expenditure in PA and in light-, moderate-, and high-intensity PA.

RESULTS

Finally, 1339 cases and 1339 controls were included. The association between PA and MI likelihood was non-linear, with significantly lower MI odds at low practice levels (≥ 500 MET·min/week), lowest odds around 1500 MET·min/week, and a plateau thereafter. Light- (in subjects older than 64 years), moderate-, and high-intensity PA produced similar benefits.

CONCLUSION

Most of the population could reduce their likelihood of MI by engaging in PA at a moderate level of intensity or, in individuals older than 64 years, at a light level of intensity.

Evidence-based risk recommendations for best practices in the training of qualified exercise professionals working with clinical populations

This systematic review examines critically "best practices" in the training of qualified exercise professionals. Particular attention is given to the core competencies and educational requirements needed for working with clinical populations. Relevant information was obtained by a systematic search of 6 electronic databases, cross-referencing, and through the authors' knowledge of the area. The level and grade of the available evidence was established. A total of 52 articles relating to best practices and (or) core competencies in clinical exercise physiology met our eligibility criteria. Overall, current literature supports the need for qualified exercise professionals to possess advanced certification and education in the exercise sciences, particularly when dealing with "at-risk" populations. Current literature also substantiates the safety and effectiveness of exercise physiologist supervised stress testing and training in clinical populations.

Evidence-based risk assessment and recommendations for physical activity clearance: Consensus Document 2011

The Physical Activity Readiness Questionnaire (PAR-Q) and the Physical Activity Readiness Medical Evaluation (PARmed-X) are internationally known preparticipation screening tools developed on the basis of expert opinion. The primary purposes of this consensus document were to seek evidence-based support for the PAR-Q and PARmed-X forms, to identify whether further revisions of these instruments are warranted, to determine how people responding positively to questions on the PAR-Q can be safely cleared without medical referral, and to develop exercise clearance procedures appropriate for various clinical conditions across the human lifespan. Seven systematic reviews were conducted, examining physical-activity-related risks and effective risk-stratification procedures for various prevalent chronic conditions. An additional systematic review assessed the risks associated with exercise testing and training of the general population. Two gap areas were identified and evaluated systematically: the role of the qualified exercise professional and the requisite core competencies required by those working with various chronic conditions; and the risks associated with physical activity during pregnancy. The risks associated with being physically inactive are markedly higher than transient risks during and following an acute bout of exercise in both asymptomatic and symptomatic populations across the lifespan. Further refinements of the PAR-Q and the PARmed-X (including online versions of the forms) are required to address the unique limitations imposed by various chronic health conditions, and to allow the inclusion of individuals across their entire lifespan. A probing decision-tree process is proposed to assist in risk stratification and to reduce barriers to physical activity. Qualified exercise professionals will play an essential role in this revised physical activity clearance process.

Exercise acts as a drug; the pharmacological benefits of exercise

The beneficial effects of regular exercise for the promotion of health and cure of diseases have been clearly shown. In this review, we would like to postulate the idea that exercise can be considered as a drug. Exercise causes a myriad of beneficial effects for health, including the promotion of health and lifespan, and these are reviewed in the first section of this paper. Then we deal with the dosing of exercise. As with many drugs, dosing is extremely important to get the beneficial effects of exercise. To this end, the organism adapts to exercise. We review the molecular signalling pathways involved in these adaptations because understanding them is of great importance to be able to prescribe exercise in an appropriate manner. Special attention must be paid to the psychological effects of exercise. These are so powerful that we would like to propose that exercise may be considered as a psychoactive drug. In moderate doses, it causes very pronounced relaxing effects on the majority of the population, but some persons may even become addicted to exercise. Finally, there may be some contraindications to exercise that arise when people are severely ill, and these are described in the final section of the review. Our general conclusion is that exercise is so effective that it should be considered as a drug, but that more attention should be paid to the dosing and to individual variations between patients.

Factors affecting the estimated maximal oxygen uptake: a follow-up study of participants in the total health promotion plan

OBJECTIVES

To elucidate the effects of risk factors for arteriosclerosis on estimated VO(2) max and obtain useful information to advise enterprise employees.

SUBJECTS

One hundred and nineteen male and 87 female enterprise employees underwent exercise tests for health evaluation in the Total Health Promotion Plan at the Fukui Occupational Health Center between April 1990 and March 1993.

METHODS

Multiple regression analysis was performed using estimated VO(2) max as the dependent variable, and percent body fat, blood pressure, blood tests, habitual physical activity, number of cigarettes smoked and alcohol consumption as independent variables in the first and second year, and for yearly changes in these variables.

RESULTS

The significant variables selected were as follows: in the first year, systolic blood pressure and percent body fat in males, and age in females; in the second year, diastolic blood pressure and habitual physical activity in males and systolic blood pressure in females; for yearly changes in each variable, cigarettes in males and percent body fat in females were selected.

CONCLUSION

It was suggested that guidance to reduce cigarettes in males, and to keep a proper percent body fat in females would be effective in maintaining the estimated VO(2) max.

Influence of electrically assisted cycling on physiological parameters in untrained subjects

Electrically assisted bicycles (EAB) as a form of transport not only offer the potential to reduce energy use and environmental impact but could also be an effective way of encouraging active living. The purpose of this study is to assess the influence of physical active commuting to work using an EAB, on physiological parameters in 20 untrained men and women. Tests were performed at three different time points over a 10-week period, including four weeks of passive (control period) and six weeks of active commuting (intervention period). ANOVA for repeated measures was used to test differences between the testing series for the most important physiological parameters: Pmax·kg(-1), V˙O2peak·kg(-1), fixed blood lactate concentration (2, 4 mmol·l(-1)). The subjects performed over a 6-week period a mean total cycling distance of 405.1±156.0 km with a weekly frequency of 4.1±1.7 days·week(-1) for men and 246.0±116.3 km with a frequency of 2.9±1.0 days·week(-1) for women. Pmax·kg(-1) significantly increased in men and women after 6 weeks of active commuting. Power output at 2 mmol·l(-1) significantly increased in women (P=0.001) but not in men (P=0.0604). Power output at 4 mmol·l(-1) significantly increased for men and women. V˙O2peak·kg(-1) did not differ. With respect to the study limitations, it is concluded that cycling to work on an EAB was effective in increasing the maximal power output and power output at 4 mmol·l(-1) in these untrained subjects. Cycling on an EAB seems to be a promising tool as a health enhancing physical activity, for those who will benefit the most in terms of health related fitness, namely the physically inactive, unfit and older people.

How many steps/day are enough? For older adults and special populations

Older adults and special populations (living with disability and/or chronic illness that may limit mobility and/or physical endurance) can benefit from practicing a more physically active lifestyle, typically by increasing ambulatory activity. Step counting devices (accelerometers and pedometers) offer an opportunity to monitor daily ambulatory activity; however, an appropriate translation of public health guidelines in terms of steps/day is unknown. Therefore this review was conducted to translate public health recommendations in terms of steps/day. Normative data indicates that 1) healthy older adults average 2,000-9,000 steps/day, and 2) special populations average 1,200-8,800 steps/day. Pedometer-based interventions in older adults and special populations elicit a weighted increase of approximately 775 steps/day (or an effect size of 0.26) and 2,215 steps/day (or an effect size of 0.67), respectively. There is no evidence to inform a moderate intensity cadence (i.e., steps/minute) in older adults at this time. However, using the adult cadence of 100 steps/minute to demark the lower end of an absolutely-defined moderate intensity (i.e., 3 METs), and multiplying this by 30 minutes produces a reasonable heuristic (i.e., guiding) value of 3,000 steps. However, this cadence may be unattainable in some frail/diseased populations. Regardless, to truly translate public health guidelines, these steps should be taken over and above activities performed in the course of daily living, be of at least moderate intensity accumulated in minimally 10 minute bouts, and add up to at least 150 minutes over the week. Considering a daily background of 5,000 steps/day (which may actually be too high for some older adults and/or special populations), a computed translation approximates 8,000 steps on days that include a target of achieving 30 minutes of moderate-to-vigorous physical activity (MVPA), and approximately 7,100 steps/day if averaged over a week. Measured directly and including these background activities, the evidence suggests that 30 minutes of daily MVPA accumulated in addition to habitual daily activities in healthy older adults is equivalent to taking approximately 7,000-10,000 steps/day. Those living with disability and/or chronic illness (that limits mobility and or/physical endurance) display lower levels of background daily activity, and this will affect whole-day estimates of recommended physical activity.

Work form affects maximum oxygen uptake for one year in workers

Our previous study suggested that the work form is related to the maximum oxygen uptake (VO(2)max). Therefore, we test the hypothesis by a longitudinal study that, besides these lifestyle-related factors, the work form increases VO(2)max among workers. Seven hundred and ninety nine males aged 37.1 ± 10.6 and 395 females aged 37.7 ± 10.5 (range: 20 to 59 yr old), who participated in The Total Health Promotion Plan (THP) at their respective workplaces twice in one year from 1997 to 1998, were selected. Data on VO(2)max were analyzed for age, systolic blood pressure (SBP), body mass index (BMI), work form (sedentary, standing, and ambulatory), exercise, and smoking. Age and the baseline variables for BMI and for VO(2)max showed significant negative relationships with a change in VO(2)max in males and females. Further, a change in the BMI showed a significant negative relationship with a change of VO(2)max in males. However, exercise habit and an ambulatory work form showed significant positive relationships with a change of VO(2)max in males. It was suggested that after adjusting for other factors in males, an ambulatory work form may be associated with an increase in VO(2)max in one year.

Do or Decline?

Research has shown that physical activity (PA) is associated with overall successful aging (SA), but it is unknown whether PA promotes each SA component in similar ways. This cross-sectional population-based cohort study investigates SA in adults aged 60 years+ using data from the Canadian Community Health Survey ( N = 12,042). Multivariate comparisons showed that, compared to those who were PA, physical inactivity was a much stronger associate of functional limitations than either chronic disease or being socially unengaged with life. This effect was not found for moderately active participants. Findings reinforce that PA, even at moderate levels, is an efficient way of optimizing biopsychosocial health, particularly functional health, in later life.

A systematic review of the evidence for Canada's Physical Activity Guidelines for Adults

This systematic review examines critically the scientific basis for Canada's Physical Activity Guide for Healthy Active Living for adults. Particular reference is given to the dose-response relationship between physical activity and premature all-cause mortality and seven chronic diseases (cardiovascular disease, stroke, hypertension, colon cancer, breast cancer, type 2 diabetes (diabetes mellitus) and osteoporosis). The strength of the relationship between physical activity and specific health outcomes is evaluated critically. Literature was obtained through searching electronic databases (e.g., MEDLINE, EMBASE), cross-referencing, and through the authors' knowledge of the area. For inclusion in our systematic review articles must have at least 3 levels of physical activity and the concomitant risk for each chronic disease. The quality of included studies was appraised using a modified Downs and Black tool. Through this search we identified a total of 254 articles that met the eligibility criteria related to premature all-cause mortality (N = 70), cardiovascular disease (N = 49), stroke (N = 25), hypertension (N = 12), colon cancer (N = 33), breast cancer (N = 43), type 2 diabetes (N = 20), and osteoporosis (N = 2). Overall, the current literature supports clearly the dose-response relationship between physical activity and the seven chronic conditions identified. Moreover, higher levels of physical activity reduce the risk for premature all-cause mortality. The current Canadian guidelines appear to be appropriate to reduce the risk for the seven chronic conditions identified above and all-cause mortality.