Light-intensity Activity Research Articles

Physical activity assessment in the general population; instrumental methods and new technologies.

The objective measurement of human movement and the quantification of energy expenditure due to physical activity is an identified need in both research and the clinical setting. Validated and well-defined reference methods (double labelled water, direct calorimetry, indirect calorimetry) are expensive and mostly limited to the laboratory setting. Therefore, in the last years, several objective measurement devices have been developed which are appropriate for field studies and clinical settings. There is no gold standard among them, as all have limitations. Pedometers are small, non-expensive, count the steps taken and give information on total physical activity, but not about physical activity patterns and behaviour. Accelerometers are expensive, save information about frequency and intensity of physical activity, but not about type of physical activity. Both pedometers and accelerometers only save information about lower body movement, but reliability about the estimation of energy expenditure is limited. Heart rate monitoring relates intensity to energy expenditure, but gives no information about physical activity. GPS watches are portable, relatively inexpensive, non-invasive and provide distance, speed, and elevation with exact time and location, but are maybe limited for the assessment of brief higher speed movement and energy expenditure. Combined motion sensors combine accelerometry with the measurement of physiological variables and share advantages of single devices and are more precise. Manufacturer software which applies activity-specific algorithms for the calculation of energy expenditure can affect energy expenditure results. Most of the devices estimate energy expenditure more accurately at light to moderate intensities; underestimation increases at very light and higher intensity activities.

The Potential Yield of Non-Exercise Physical Activity Energy Expenditure in Public Health

Previous work has shown prospective associations between total daily physical activity energy expenditure and various health outcomes including metabolic risk. Limited evidence is available on the health benefits of standing and light-intensity activity. Therefore, these behaviours are not supported in contemporary physical activity guidelines. Moreover, people may be more willing to replace sedentary activities with standing or light activities that can be incorporated into their daily lives, rather than activities of moderate intensity, as there are fewer potential barriers. With the rapid advancement of objective physical activity monitoring there is now potential to explore total daily physical activity energy expenditure in more depth. This article highlights the need for further research into all areas of total daily physical activity energy expenditure, in particular standing and light-intensity activities. Future physical activity guidelines may benefit from the inclusion of recommendations on physical activity energy expenditure rather than solely focusing on activities of a moderate or vigorous intensity.

Light Intensity physical activity and sedentary behavior in relation to body mass index and grip strength in older adults: cross-sectional findings from the Lifestyle Interventions and Independence for Elders (LIFE) study.

BackgroundIdentifying modifiable determinants of fat mass and muscle strength in older adults is important given their impact on physical functioning and health. Light intensity physical activity and sedentary behavior are potential determinants, but their relations to these outcomes are poorly understood. We evaluated associations of light intensity physical activity and sedentary time—assessed both objectively and by self-report—with body mass index (BMI) and grip strength in a large sample of older adults.MethodsWe used cross-sectional baseline data from 1130 participants of the Lifestyle Interventions and Independence for Elders (LIFE) study, a community-dwelling sample of relatively sedentary older adults (70-89 years) at heightened risk of mobility disability. Time spent sedentary and in light intensity activity were assessed using an accelerometer worn for 3–7 days (Actigraph GT3X) and by self-report. Associations between these exposures and measured BMI and grip strength were evaluated using linear regression.ResultsGreater time spent in light intensity activity and lower sedentary times were both associated with lower BMI. This was evident using objective measures of lower-light intensity, and both objective and self-reported measures of higher-light intensity activity. Time spent watching television was positively associated with BMI, while reading and computer use were not. Greater time spent in higher but not lower intensities of light activity (assessed objectively) was associated with greater grip strength in men but not women, while neither objectively assessed nor self-reported sedentary time was associated with grip strength.ConclusionsIn this cross-sectional study, greater time spent in light intensity activity and lower sedentary times were associated with lower BMI. These results are consistent with the hypothesis that replacing sedentary activities with light intensity activities could lead to lower BMI levels and obesity prevalence among the population of older adults. However, longitudinal and experimental studies are needed to strengthen causal inferences.

A description of the volume and intensity of sporadic physical activity among adults.

BackgroundEmerging evidence indicates that accumulating physical activity in periods of less than 10 minutes, termed sporadic physical activity (SPA), has similar effects on health as a similar volume of bouted physical activity (BPA). The purpose of this study was to describe the volume and intensity of SPA in adults.MethodsParticipants consisted of a representative sample of 6040 adults aged 20 years and older from the 2003–2006 U.S. National Health and Examination Nutrition Survey. Physical activity was measured over 7 days using Actigraph AM-7164 accelerometers. Each minute of accelerometer data was initially categorized by intensity (sedentary, light, moderate-to-vigorous), and then non-sedentary time was categorized as following a BPA or SPA pattern (≥ or < 10 consecutive minutes).ResultsAmerican adults accumulated 103 minutes/day of SPA of an intensity, which represented 27% of their total (BPA + SPA) daily physical activity. Only 3 minutes/day of the SPA was of a moderate-to-vigorous intensity; however, participants accumulated 16 minutes/day of moderate-to-vigorous activity embedded within light intensity BPA. This embedded moderate-to-vigorous activity represented 85% of total daily moderate-to-vigorous activity.ConclusionsSPA accounted for about a quarter of total daily physical activity. While the amount of moderate-to-vigorous SPA was minimal, a significant amount of moderate-to-vigorous activity was accumulated within bouts of primarily light intensity activity.

Effects of premorbid physical activity on stroke severity and post-stroke functioning.

To explore the impact of premorbid physical activity on stroke severity and functioning, measured by activities of daily living, gait and balance during the acute period of first-ever stroke and at one-year follow-up. Acute phase and one-year follow-up registrations of 183 patients with first-ever stroke or transient ischaemic attack were included in the study. Gender, age, education, living arrangements, body mass index, smoking, hypertension, stroke classification and use of walking aids were recorded. Premorbid physical activity was recorded with the Walking Habits questionnaire. The outcomes post-stroke were the National Institutes of Health Stroke Scale, the Modified Ranking Scale, Barthel ADL Index, Maximal Walking Speed and Berg Balance Scale. Significant associations (p < 0.05) were found between the participants` pre-stroke "duration of regular walks" and functioning on all outcomes in the acute phase of stroke. Participants who walked for more than 30 min each time achieved significantly better results. The measures of gait and balance showed similar associations (p < 0.05) at one-year follow-up. There are significant associations between premorbid walking habits and functional status after first-ever stroke. Weekly light-intensity activity, such as walking for more than 30 min, may have a sustained impact on functioning after stroke.

Mobility disability and the pattern of accelerometer-derived sedentary and physical activity behaviors in people with multiple sclerosis

ObjectiveLow physical activity and high sedentary behavior levels are major concerns in persons with multiple sclerosis (MS) and these differ depending on the level of mobility disability. However, the manner in which daily activity is accumulated is currently unknown in this population. MethodsA secondary analysis was performed on a combined data set of persons with MS from two previous investigations of physical activity and symptomatic or quality of life outcomes in the United States over a two year period (2007–2009). Mobility disability status was determined using the Patient Determined Disease Steps (PDDS) while activity behavior was objectively monitored using an ActiGraph accelerometer for 7days. ResultsPersons with MS who have mobility disability were involved in sedentary behavior, light and moderate intensity activity for 65%, 34% and 1% of the day, respectively compared to 60%, 37%, and 3%, respectively in those without mobility disability (p<0.05). Breaks in sedentary time did not differ by mobility disability status. Compared to those without mobility disability, the average number of sedentary bouts longer than 30min was greater in those with mobility disability (p=0.016). ConclusionPersons with MS with mobility disability are less active, engage in more sedentary behavior and accumulate prolonged sedentary bouts.

Effects of Physical Exercise on Cardiovascular Diseases: Biochemical, Cellular, and Organ Effects.

It is well recognised that regular exercise is cardioprotective. On the other hand, sedentariety is an established risk factor for cardiovascular diseases. Furthermore, several clues suggest that exercise capacity is a strong predictor of risk of death from any cause in both healthy subjects and in those with cardiovascular diseases. However, the exact mechanisms through which regular physical activity confers cardiovascular protection are not yet well understood. Exercise probably acts at multiple levels. One possibility is that regular exercise modifies genes expression, thereby changing the production of bioactive molecules such as proteins and enzymes; another potential site of action is on the mechanisms of cardiovascular regulation during effort, which are improved after periods of training; finally, exercise can affect endothelial and platelet functions, thus reducing the risks of atherosclerosis and consequently the risk of infarction and stroke. This special issue focuses on potential beneficial mechanisms by which exercise operates to confer protection against cardiovascular diseases. The interesting paper by S. Heber and I. Volf reviews the effects of inactivity and training on platelet functions. In their literature review, they conclude that regular physical activity diminishes or prevents platelet activation in response to acute exercise and that habitual physical activity also positively modulates platelet functions. They also conclude that these effects support the well-recognised relation between exercise and the risk for cardiovascular events, as a physically active lifestyle dramatically reduces cardiovascular mortality. In another intriguing review, C.-Y. Hsu et al. focus on the important topic of the effects of exercise training on autonomic function in chronic heart failure (CHF). Exercise intolerance is one of the major and disturbing symptoms in these patients. Increased sympathetic tone and decreased parasympathetic activity have been often reported in CHF and these phenomena are associated with a poor survival. Data from this review indicate that participation in exercise training programs induces beneficial effects on autonomic function in CHF patients. They also point out that further research could examine additional aspects of the effects of exercise training in this population, such as the impact on the responses to exercise training in different levels of CHF severity, the possibility that a threshold intensity may be needed to affect cardiac autonomic function, and the type of exercise that should be recommended to achieve the highest positive effects on sympathovagal balance. In a third review by A. Crisafulli et al., the complex issue of cardiovascular reflexes during exercise is addressed. During exercise, the neural mechanisms controlling the cardiovascular apparatus regulate cardiac output and arteriolar tone in order to counteract the exercise-induced vasodilation due to functional sympatholysis in the working muscle. These cardiovascular adjustments guarantee adequate perfusion to vital organs (the brain and the heart) and to the working muscles as well as adequate washout of exercise-induced by-products. Moreover, these mechanisms prevent excessive increments in blood pressure. In this review, authors summarise neural reflexes operating during dynamic exercise, particularly their interaction. They point out that cardiovascular regulation during exercise is achieved through the contemporary integration and interaction of input arising from motor cortex (central command), skeletal muscle receptors (exercise pressor reflex), and arterial baroreceptors. They also conclude that further research is warranted to better understand how these reflexes interact during effort. The last interesting review by R. B. Batacan Jr. et al. is about the effects of light intensity activity on cardiovascular risk factors. These authors claim that there is little support for the role of light intensity activity to reduce cardiovascular disease risk factors and that further studies are needed to establish the value of light intensity physical activity in reducing cardiovascular risk factors. Finally, the research paper by N. G. Rocha et al. aims at evaluating the acute effects of exercise on endothelial functions in early metabolic syndrome. They find that these subjects, despite being free of symptoms, present with an early impairment of endothelial function. Moreover, they put forward the hypothesis that the analysis of some biomarkers changes could be potentially useful to develop preventive measures before the onset of overt metabolic syndrome. Collectively, these manuscripts confirm that sedentariety is harmful for the cardiovascular system. Moreover, exercise not only exerts positive effect on cardiovascular functions and reduces the risks of cardiovascular diseases (primary prevention), but could also revert cardiovascular disease and play a preventive role in the progression of pathological conditions (secondary/tertiary prevention).

Effects of Light Intensity Activity on CVD Risk Factors: A Systematic Review of Intervention Studies.

The effects of light intensity physical activity (LIPA) on cardiovascular disease (CVD) risk factors remain to be established. This review summarizes the effects of LIPA on CVD risk factors and CVD-related markers in adults. A systematic search of four electronic databases (PubMed, Academic Search Complete, SPORTDiscus, and CINAHL) examining LIPA and CVD risk factors (body composition, blood pressure, glucose, insulin, glycosylated hemoglobin, and lipid profile) and CVD-related markers (maximal oxygen uptake, heart rate, C-reactive protein, interleukin-6, tumor necrosis factor-alpha, and tumor necrosis factor receptors 1 and 2) published between 1970 and 2015 was performed on 15 March 2015. A total of 33 intervention studies examining the effect of LIPA on CVD risk factors and markers were included in this review. Results indicated that LIPA did not improve CVD risk factors and CVD-related markers in healthy individuals. LIPA was found to improve systolic and diastolic blood pressure in physically inactive populations with a medical condition. Reviewed studies show little support for the role of LIPA to reduce CVD risk factors. Many of the included studies were of low to fair study quality and used low doses of LIPA. Further studies are needed to establish the value of LIPA in reducing CVD risk.

The impact of parenthood on Canadians' objectively measured physical activity: an examination of cross-sectional population-based data.

BackgroundParenthood has been associated with declines in leisure-time exercise and moderate-to-vigorous physical activity (MVPA), but less is known about its impact on sedentary time and light-intensity activity. Although the health benefits of MVPA are well established, a growing body of research has been showing that even after controlling for MVPA levels, a detrimental dose–response association exists between sedentary time and adverse health outcomes and a beneficial dose–response association exists for light-intensity activity.MethodsThis study examined the impact of parenthood, the number of children in the home, and the age of the youngest child on objectively measured physical activity (i.e., accelerometer derived daily minutes of sedentary, light, and MVPA) among a nationally representative cross-sectional sample of 2234 men and women who participated in the 2009–2011 Canadian Health Measures Survey.ResultsAfter controlling for sociodemographic variables, ANCOVAs indicated that parents engaged in more light activity but less MVPA than non-parents and women whose youngest child was aged 12–15 years were more sedentary than women without children. Among both men and women, having a child <6 years of age in the home was associated with the greatest amount of light activity and lowest MVPA.ConclusionsModest differences emerged between the physical activity level of parents and non-parents for both genders and across intensity levels. In general, parenthood was associated with less MVPA and more light-intensity activity, and more differences emerged among women compared to men. More research is needed before conclusions can be drawn regarding the health consequences of these differences.

Body Mass Index: Accounting for Full Time Sedentary Occupation and 24-Hr Self-Reported Time Use

ObjectivesWe used linked existing data from the 2006–2008 American Time Use Survey (ATUS), the Current Population Survey (CPS, a federal survey that provides on-going U.S. vital statistics, including employment rates) and self-reported body mass index (BMI) to answer: How does BMI vary across full time occupations dichotomized as sedentary/non-sedentary, accounting for time spent in sleep, other sedentary behaviors, and light, moderate, and vigorous intensity activities?MethodsWe classified time spent engaged at a primary job (sedentary or non-sedentary), sleep, and other non-work, non-sleep intensity-defined behaviors, specifically, sedentary behavior, light, moderate, and vigorous intensity activities. Age groups were defined by 20–29, 30–39, 40–49, and 50–64 years. BMI groups were defined by 18.5–24.9, 25.0–27.4, 27.5–29.9, 30.0–34.9, and ≥35.0 kg/m2. Logistic and linear regression were used to examine the association between BMI and employment in a sedentary occupation, considering time spent in sleep, other non-work time spent in sedentary behaviors, and light, moderate, and vigorous intensity activities, sex, age race/ethnicity, and household income.ResultsThe analysis data set comprised 4,092 non-pregnant, non-underweight individuals 20–64 years of age who also reported working more than 7 hours at their primary jobs on their designated time use reporting day. Logistic and linear regression analyses failed to reveal any associations between BMI and the sedentary/non-sedentary occupation dichotomy considering time spent in sleep, other non-work time spent in sedentary behaviors, and light, moderate, and vigorous intensity activities, sex, age, race/ethnicity, and household income.ConclusionsWe found no evidence of a relationship between self-reported full time sedentary occupation classification and BMI after accounting for sex, age, race/ethnicity, and household income and 24-hours of time use including non-work related physical activity and sedentary behaviors. The various sources of error associated with self-report methods and assignment of generalized activity and occupational intensity categories could compound to obscure any real relationships.

Comparison of total energy expenditure assessed by two devices in controlled and free-living conditions

The objective of this study was to evaluate the validity of total energy expenditure (TEE) provided by Actiheart® and Armband®. Normal-weight adult volunteers wore both devices either for 17 hours in a calorimetric chamber (CC, n = 49) or for 10 days in free-living conditions (FLC) outside the laboratory (n = 41). The two devices and indirect calorimetry or doubly labelled water, respectively, were used to estimate TEE in the CC group and FLC group. In the CC, the relative value of TEE error was not significant (p > 0.05) for Actiheart® but significantly different from zero for Armband®, showing TEE underestimation (−4.9%, p < 0.0001). However, the mean absolute values of errors were significantly different between Actiheart® and Armband®: 8.6% and 6.7%, respectively (p = 0.05). Armband® was more accurate for estimating TEE during sleeping, rest, recovery periods and sitting–standing. Actiheart® provided better estimation during step and walking. In FLC, no significant error in relative value was detected. Nevertheless, Armband® produced smaller errors in absolute value than Actiheart® (8.6% vs. 12.8%). The distributions of differences were more scattered around the means, suggesting a higher inter-individual variability in TEE estimated by Actiheart® than by Armband®. Our results show that both monitors are appropriate for estimating TEE. Armband® is more effective than Actiheart® at the individual level for daily light-intensity activities.

Light-Intensity Activity Attenuates Functional Decline in Older Cancer Survivors

While moderate- to vigorous-intensity physical activities (MVPA) confer the greatest health benefits, evidence suggests that light-intensity activities are also beneficial, particularly for older adults and individuals with moderate to severe comorbidities. To examine cross-sectional and longitudinal associations between light-intensity activity and physical function in older cancer survivors at increased risk for age- and treatment-related comorbidities, including accelerated functional decline. The analysis included data from 641 breast, prostate, and colorectal cancer survivors (54% female) age 65 yr and older who participated in a 1-yr home-based diet and exercise intervention designed to reduce the rate of physical function decline. ANCOVA was used to compare means of physical function across levels of PA intensity (low-light [LLPA]: 1.5-2.0 METs; high-light [HLPA]: 2.1-2.9 METs; MVPA: ≥3.0 METs). In cross-sectional analyses, increasing tertiles of light-intensity activity were associated with higher scores for all three measures of physical function (all P values <0.005), after adjusting for age, sex, body mass index, comorbidity, symptoms, and MVPA. Associations were stronger for HLPA than for LLPA. Compared with survivors who had decreased MVPA or maintained stable MVPA and HLPA at the postintervention follow-up, those who had increased HLPA, but had decreased MVPA or maintained stable MVPA, reported higher physical function scores (LS means [95% confidence interval]: SF-36 Physical Function Subscale: -5.58 [-7.96 to -3.20] vs -2.54 [-5.83 to 0.75], P = 0.14; Basic Lower Extremity Function: -2.00 [-3.45 to -0.55] vs 0.28 [-1.72 to 2.28], P = 0.07; Advanced Lower Extremity Function: -2.58 [-4.00 to -1.15] vs 0.44 [-1.52 to 2.40], P = 0.01). Our findings suggest that increasing light-intensity activities, especially HLPA, may be a viable approach to reducing the rate of physical function decline in individuals who are unable or reluctant to initiate or maintain adequate levels of moderate-intensity activities.

Relation of physical activity time to incident disability in community dwelling adults with or at risk of knee arthritis: prospective cohort study

Objective To investigate whether objectively measured time spent in light intensity physical activity is related to incident disability and to disability progression.Design Prospective multisite cohort study from September 2008 to...

The association between physical activity and reduced body fat lessens with age — Results from a cross-sectional study in community-dwelling older adults

IntroductionThe aim of this study was to describe the relationship between accelerometer-determined physical activity (PA) and adiposity in community-dwelling older adults. In addition, we were interested in comparing the extent of correlation between questionnaire and accelerometer determined PA. Methods636 community-dwelling older adults (66±7years) were studied. Adiposity was measured using dual-energy X-ray absorptiometry and BMI was calculated. We measured minutes/day spent in sedentary, light, moderate and vigorous intensity activity using both questionnaires and Actigraph GT1M accelerometers. ResultsParticipants spent a median of 583(IQR 522–646), 225(176–271), 27(12–45) and 0(0–0) minutes in sedentary, light, moderate and vigorous activities respectively. There was a non linear dose–response inverse relationship between activity intensity and adiposity. After adjusting for age, sex and other levels of PA, for every 10minute increase in activity, total body fat decreased by 169g(95% CI 61–277), 905g(632–1178), and 2208g(759–3657) for light, moderate and vigorous activities respectively. There was an interaction between age and activity; as age increased, the magnitude of the effects of light and moderate activities on adiposity decreased. Sedentary minutes were not associated with adiposity after adjusting for time spent at other PA intensities. Questionnaire measures of PA were weakly correlated with body fat measures when compared to accelerometer determined PA. ConclusionBoth the amount and intensity of PA, but not sedentary time, have an independent dose–response association with adiposity. The association is much stronger using objective assessment compared to questionnaire. The magnitude of these associations decrease with age suggesting that physical activity programmes may need to be modified with increasing age.

Be it resolved: plain radiography or MRI – which is better in assessing outcome in clinical trials?

Be it resolved: plain radiography or MRI – which is better in assessing outcome in clinical trials?

Breaking up prolonged sitting with light-intensity walking improves postprandial glycemia, but breaking up sitting with standing does not

To explore the effects of breaking up prolonged sitting time with standing or light-intensity walking on a range of cardiometabolic risk markers. A randomised three-period, three-treatment acute crossover trial. Ten non-obese adults took part in three trials: (1) uninterrupted sitting; (2) seated with 2-min bouts of standing every 20 min; and (3) seated with 2-min bouts of light-intensity walking every 20 min. Two standardised test drinks (total 80.3 carbohydrate, 50 g fat) were provided after an initial 1-h period of uninterrupted sitting. Plasma glucose and blood pressure were assessed hourly to calculate area under the curve. Total cholesterol, HDL, and triglycerides were assessed at baseline and 5-h. ANOVAs were used to explore between-trial differences. Glucose area under the curve was lower in the activity-break condition compared to the uninterrupted sitting and standing-break conditions: mean area under the curve 18.5 (95% CI 17, 20), 22.0 (20.5, 23.5), and 22.2 (20.7, 23.7) mmol L/5-h, respectively, p<0.001; no difference between uninterrupted sitting and standing-break conditions (p>0.05). Systolic and diastolic blood pressure area under the curve did not differ significantly between conditions, nor did responses in lipid parameters (p>0.05). This study suggests that interrupting sitting time with frequent brief bouts of light-intensity activity, but not standing, imparts beneficial postprandial responses that may enhance cardiometabolic health. These findings may have importance in the design of effective interventions to reduce cardiometabolic disease risk.

Older adults’ time in sedentary, light and moderate intensity activities and correlates: Application of Australian Time Use Survey

Understanding how older adults spend their time between active and sedentary activities is an important aspect of healthy ageing. This study examined the time spent in all-domains of sedentary, light and moderate intensity physical activities in old age and identified high-risk groups. A cross-sectional analysis of Australian 2006 Time Use Survey. Participants comprised non-working older adults with at least one 24-h time use diary (n=992). Primary activities were recoded by activity domain and intensity. Multivariate logistic regression analyses were used to calculate the odds ratios of having high sedentary time, low light-intensity physical activity (LIPA), and being insufficiently active (<30 min/day of moderate-to-vigorous physical activity, MVPA) by sociodemographic variables. Older adults spent 223 and 121 min/day of their waking time in LIPA and MVPA, respectively, mostly (88%) attributed to household chores. One third of participants spent ≥600 min/day in sedentary activities, 63% spent ≥180 min/day in LIPA, 85% achieved sufficient levels of MVPA by all domains, but only 30% of participants by the leisure/transport domains. Neither age nor socio-economic indicators were associated with insufficient MVPA. Marital status and living arrangement were significant correlates of low MVPA and LIPA but moderated by gender. The only correlate of high sedentary time (>10 h/day) was disability or long-term health condition. The majority of older Australians are sufficiently active when considering all domains. Household domain is the main source of LIPA and MVPA. In old age, prolonged sitting is associated with disability. Marital status and living arrangements can be used to identify physically inactive seniors.

Associations between objectively assessed and self-reported sedentary time with mental health in adults: an analysis of data from the Health Survey for England

ObjectiveThere is increasing interest in the association between sedentary behaviour and mental health, although most studies have relied solely on self-reported measures, thus making results prone to various biases. The...

Office Workers' Objectively Measured Sedentary Behavior and Physical Activity During and Outside Working Hours

To examine objectively determined sedentary behavior and physical activity (PA) during and outside working hours in full-time office workers. A total of 170 participants wore an ActiGraph GT1M accelerometer for 7 days. Time spent sedentary (<100 counts/min), in light-intensity PA (100 to 1951 counts/min), and moderate-to-vigorous PA (≥1952 counts/min) was calculated for workdays (including working hours and nonworking hours) and nonworkdays. Participants accumulated significantly higher levels of sedentary behavior (68% vs 60%) and lower levels of light-intensity activity (28% vs 36%) on workdays in comparison with nonworkdays. Up to 71% of working hours were spent sedentary. Individuals who were most sedentary at work were also more sedentary outside work. Those who are most sedentary at work do not compensate by increasing their PA or reducing their sedentary time outside work. Occupational interventions should address workplace and leisure-time sedentary behavior.

Ethnic disparities in objectively measured physical activity may be due to occupational activity

ObjectivesWe examined whether Mexican American adults report occupations that involve higher levels of objectively assessed physical activity compared with Non-Hispanic White and Black adults, and if the differences were independent of income. MethodsData from the 2003–2004 National Health and Nutrition Examination Survey (NHANES; N=2707) were analyzed in 2012–2013. An existing classification scheme was used to classify self-reported occupation as sedentary, low-active, or moderately active. From NHANES accelerometer data, proportion of wear time was stratified by intensity. ResultsA dose–response relationship was found such that workers in more active occupations spent more time in light-intensity activity and less time engaged in sedentary activities. The findings did not suggest a compensation effect for moderate-to-vigorous intensity physical activity. Mexican American adults engaged in more activity than Non-Hispanic Black or White adults for incomes between $10,000 and $64,999. ConclusionsMexican American adults may have higher total physical activity levels in NHANES because of occupational activity, particularly among lower income households. To the extent that light-intensity activity may provide health benefits, occupational activity may partly explain the Hispanic paradox.