Caroline R. Richardson

Guide to the Assessment of Physical Activity: Clinical and Research Applications A Scientific Statement From the American Heart Association

The deleterious health consequences of physical inactivity are vast, and they are of paramount clinical and research importance. Risk identification, benchmarks, efficacy, and evaluation of physical activity behavior change initiatives for clinicians and researchers all require a clear understanding of how to assess physical activity. In the present report, we have provided a clear rationale for the importance of assessing physical activity levels, and we have documented key concepts in understanding the different dimensions, domains, and terminology associated with physical activity measurement. The assessment methods presented allow for a greater understanding of the vast number of options available to clinicians and researchers when trying to assess physical activity levels in their patients or participants. The primary outcome desired is the main determining factor in the choice of physical activity assessment method. In combination with issues of feasibility/practicality, the availability of resources, and administration considerations, the desired outcome guides the choice of an appropriate assessment tool. The decision matrix, along with the accompanying tables, provides a mechanism for this selection that takes all of these factors into account. Clearly, the assessment method adopted and implemented will vary depending on circumstances, because there is no single best instrument appropriate for every situation. In summary, physical activity assessment should be considered a vital health measure that is tracked regularly over time. All other major modifiable cardiovascular risk factors (diabetes mellitus, hypertension, hypercholesterolemia, obesity, and smoking) are assessed routinely. Physical activity status should also be assessed regularly. Multiple physical activity assessment methods provide reasonably accurate outcome measures, with choices dependent on setting-specific resources and constraints. The present scientific statement provides a guide to allow professionals to make a goal-specific selection of a meaningful physical activity assessment method.

A meta-analysis of pedometer-based walking interventions and weight loss

PURPOSE Cross-sectional studies show that individuals who walk more tend to be thinner than those who walk less. This does not mean, however, that the association between higher step counts and lower weight is causal or that encouraging sedentary individuals to increase step counts helps them lose weight. METHODS In this meta-analysis, we searched 6 electronic databases and contacted pedometer experts to identify pedometer-based walking studies without a dietary intervention that reported weight change as an outcome. We included randomized controlled trials and prospective cohort studies published after January 1, 1995, in either English or Japanese, with 5 or more adult participants and at least 1 cohort enrolled in a pedometer-based walking intervention lasting at least 4 weeks. RESULTS Nine studies met the study inclusion criteria. Cohort sample size ranged from 15 to 106, for a total of 307 participants, 73% of whom were women and 27% of whom were men. The duration of the intervention ranged from 4 weeks to 1 year, with a median duration of 16 weeks. The pooled estimate of mean weight change from baseline using a fixed-effects model and combining data from all 9 cohorts was −1.27 kg (95% confidence interval, −1.85 to −0.70 kg). Longer intervention duration was associated with greater weight change. On average, participants lost 0.05 kg per week during the interventions. CONCLUSION Pedometer-based walking programs result in a modest amount of weight loss. Longer programs lead to more weight loss than shorter programs.

Objectively measured physical activity of USA adults by sex, age, and racial/ethnic groups: a cross-sectional study.

BackgroundAccelerometers were incorporated in the 2003–2004 National Health and Nutritional Examination Survey (NHANES) study cycle for objective assessment of physical activity. This is the first time that objective physical activity data are available on a nationally representative sample of U.S. residents. The use of accelerometers allows researchers to measure total physical activity, including light intensity and unstructured activities, which may be a better predictor of health outcomes than structured activity alone. The aim of this study was to examine objectively determined physical activity levels by sex, age and racial/ethnic groups in a national sample of U.S. adults.MethodsData were obtained from the 2003–2004 NHANES, a cross-sectional study of a complex, multistage probability sample of the U.S. population. Physical activity was assessed with the Actigraph AM-7164 accelerometer for seven days following an examination. 2,688 U.S. adults with valid accelerometer data (i.e. at least four days with at least 10 hours of wear-time) were included in the analysis. Mean daily total physical activity counts, as well as counts accumulated in minutes of light, and moderate-vigorous intensity physical activity are presented by sex across age and racial/ethnic groups. Generalized linear modeling using the log link function was performed to compare physical activity in sex and racial/ethnic groups adjusting for age.ResultsPhysical activity decreases with age for both men and women across all racial/ethnic groups with men being more active than women, with the exception of Hispanic women. Hispanic women are more active at middle age (40–59 years) compared to younger or older age and not significantly less active than men in middle or older age groups (i.e. age 40–59 or age 60 and older). Hispanic men accumulate more total and light intensity physical activity counts than their white and black counterparts for all age groups.ConclusionPhysical activity levels measured objectively by accelerometer demonstrated that Hispanic men are, in general, more active than their white and black counterparts. This appears to be in contrast to self-reported physical activity previously reported in the literature and identifies the need to use objective measures in situations where the contribution of light intensity and/or unstructured physical activity cannot be assumed homogenous across the populations of interest.

Physical activity and mortality across cardiovascular disease risk groups

PURPOSE Several cohort studies suggest that sedentary individuals have an increased risk of death compared with individuals who are physically active. Most of these studies have been conducted in highly selected patient populations who tend to be healthier and are from higher socioeconomic status (SES) groups. We examined the impact of a sedentary lifestyle on mortality by cardiovascular disease (CVD) risk group in a national sample of U.S. adults who represent a wide range of activity levels, health conditions, and SES groups. METHODS Using data from the HRS, a nationally representative, observational study of 9824 U.S. adults aged 51-61 yr in 1992, we estimated the relative risk of death comparing sedentary individuals with those who are physically active by CVD risk group in a multivariate logistic regression model. RESULTS Even after adjusting for confounders, regular moderate to vigorous physical activity was associated with substantially lower overall mortality (odds ratio (OR) = 0.62 (95% CI 0.44-0.86)) compared with sedentary individuals. High CVD risk individuals (21% of the population) accounted for 64% of deaths attributable to a sedentary lifestyle. Those with high CVD risk had the most significant benefit from being active (regular moderate to vigorous exercisers OR = 0.55 (95% CI 0.31-0.97) and occasional or light exercisers OR 0.55 (95% CI 0.41-0.74)) compared with high CVD risk individuals who were sedentary. CONCLUSION A sedentary lifestyle is associated with a higher risk of death in preretirement-aged U.S. adults. Individuals with high CVD risk appear to get the largest benefit from being physically active. Physical activity interventions targeting high CVD risk individuals should be a medical and public health priority.

A randomized trial comparing structured and lifestyle goals in an internet-mediated walking program for people with type 2 diabetes

BackgroundThe majority of individuals with type 2 diabetes do not exercise regularly. Pedometer-based walking interventions can help; however, pedometer-based interventions targeting only total daily accumulated steps might not yield the same health benefits as physical activity programs specifying a minimum duration and intensity of physical activity bouts.MethodsThis pilot randomized trial compared two goal-setting strategies: 1) lifestyle goals targeting total daily accumulated step counts and 2) structured goals targeting bout steps defined as walking that lasts for 10 minutes or longer at a pace of at least 60 steps per minute. We sought to determine which goal-setting strategy was more effective at increasing bout steps. Participants were sedentary adults with type 2 diabetes. All participants: wore enhanced pedometers with embedded USB ports; uploaded detailed, time-stamped step-count data to a website called Stepping Up to Health; and received automated step-count feedback, automatically calculated goals, and tailored motivational messages throughout the six-week intervention. Only the automated goal calculations and step-count feedback differed between the two groups. The primary outcome of interest was increase in steps taken during the previously defined bouts of walking (lasting at least 10 minutes or longer at a pace of at least 60 steps per minute) between baseline and end of the intervention.ResultsThirty-five participants were randomized and 30 (86%) completed the pilot study. Both groups significantly increased bout steps, but there was no statistically significant difference between groups. Among study completers, bout steps increased by 1921 ± 2729 steps a day. Those who received lifestyle goals were more satisfied with the intervention (p = 0.006) and wore the pedometer more often (p < 0.001) than those who received structured goals.ConclusionIn this six-week intervention, Lifestyle Goals group participants achieved increases in bout steps comparable to the increases seen in the Structured Goals group, representing almost a mile a day of additional moderate intensity bout activity. Pedometer-based walking programs that emphasize total accumulated step counts are more acceptable to participants and are as effective at increasing moderate intensity bouts of physical activity as programs that use structured goals.Trial registrationNCT00151021

A pilot study of an Internet walking program and pedometer in COPD

BACKGROUND Higher levels of physical activity are associated with better functional status, fewer hospital admissions, and lower mortality. In this pilot study, we examined the feasibility and safety of a novel program that combines a pedometer with a website to increase walking. METHODS 27 persons with stable COPD wore the Omron HJ-720ITC pedometer and used the website for 90 days. They uploaded step-count data to the study server using their home computer and received an email each week with their individualized step-count goal. The website provided step-count feedback, education, and motivational content. Subjects participated in a monthly semi-structured interview by telephone. Subjects reported changes in medical condition by telephone or on the website. Paired T-tests assessed change in daily step counts. RESULTS Subjects were males, mean age 72 ± 8 years, with moderate COPD, FEV(1) 1.57 ± 0.48 L (55 ± 16% predicted). 87% and 65% reported no problems using the pedometer and website, respectively. At month 3, 96% reported it was true that they knew their step count goal every day, and 52% reported that they were able to reach their goal. 95% of participants said they would recommend the walking program to another person with COPD. Eight subjects experienced breathing problems unrelated to the intervention. In 24 subjects with step counts at baseline and month 3, there was a significant increase of 1263 steps per day (approximately 1.0 km), p = 0.0054. CONCLUSIONS The use of a website and pedometer was feasible and safe, and persons increased their daily walking.

Are adults with bipolar disorder active? Objectively measured physical activity and sedentary behavior using accelerometry

BACKGROUND Little is known about physical activity and sedentary behavior of adults with bipolar disorder (BP). Physical activity and sedentary behaviors may be modifiable factors associated with elevated rates of obesity, diabetes, cardiovascular disease, metabolic syndrome, and mortality in adults with BP. METHODS Sixty adult outpatients treated for BP (> 18 yr) wore accelerometers for seven consecutive days. Each minute epoch was assigned an activity level based on the number of counts per minute; sedentary(<100 counts), light(101-1951 counts), or moderate/vigorous(>1952 counts). Adults with BP were matched 1:1 to users and non-users of mental health services (MHS) (NHANES 2003-2004) by gender, closest BMI, and age. RESULTS On average, adults with BP wore actigraphs over 17 h/day. The majority of monitoring time (78%) was classified as sedentary (approximately 13.5h/day). Light physical activity accounted for 21% of the monitoring time/day (215 min/day). None achieved 150 min/wk of moderate/vigorous activity as recommended by national guidelines. Adults with BP were significantly less active and more sedentary than MHS users and non-users in NHANES 2003-2004 (p<0.01). LIMITATIONS Majority of the participants were relatively asymptomatic with most (87%) having no more than mild depressive symptoms and none experiencing severe manic symptoms. The sedating effects of medications on physical activity were not investigated. CONCLUSION From clinical perspectives, these findings justify physical activity interventions targeting adults with BP as a possible means to improve their physical and mental health and to reduce the elevated risk of commonly observed medical comorbidities in this high-risk population.

TYPE OF PHYSICAL ACTIVITY GOAL INFLUENCES PARTICIPATION IN HEALTHY MIDLIFE WOMEN

BACKGROUND Regular physical activity can help to prevent cardiovascular disease in women. Understanding midlife womens exercise goals could offer insight into their motivational facilitators and barriers, and assist in the development of better primary prevention strategies for this population. OBJECTIVES We sought to investigate the relationship between midlife womens physical activity goals and their physical activity participation over time. METHODS A random sample of healthy, midlife women (40-60 years of age) was selected to participate in a longitudinal study (n = 156). This study fit a linear mixed model to the data to investigate the fixed effects of physical activity goals on physical activity participation, controlling for Body Mass Index (BMI) and Social Support. Mediational analyses were conducted to investigate whether commitment and planning mediated these results. RESULTS There were significant differences between participants with distinct types of goals on physical activity participation over time (i.e., baseline, 1 month, and 1 year postbaseline), controlling for the effects of BMI and Social Support. Participants with Weight Loss and Health Benefits goals participated in significantly less physical activity than those with Sense of Well-being and Stress Reduction goals. Commitment and Planning each mediated the relationship between participant goals and their physical activity participation. CONCLUSIONS These data suggest having physical activity goals that aim to decrease weight or benefit health may not bode well for healthy midlife women who desire to sustain physically active lives. Instead, health care providers and health promotion specialists might better facilitate long-term participation among healthy women if they emphasize physical activity as a means to enhance their quality of life.

Increasing lifestyle physical activity in patients with depression or other serious mental illness.

People with severe and persistent mental illness are more likely to be overweight and to suffer from obesity-related illnesses such as diabetes and heart disease than healthy individuals. Lifestyle change interventions that emphasize integrating physical activity into daily life have not been studied extensively in people with mental illness. The authors present the results of an initial feasibility study of a lifestyle modification program for individuals with serious mental illness. Thirty-nine individuals with depression or other serious mental illness were recruited from three different mental health facilities to attend an 18-week lifestyle intervention program promoting physical activity and healthy eating. At each session, participants discussed topics related to healthy lifestyle changes and participated in group walks. Data were collected at baseline, 6 weeks, and 18 weeks. The results demonstrated that individuals who have depression and other serious mental illnesses can participate in a lifestyle intervention program. Participants who attended the final follow-up session had lost weight over the course of the intervention. Study retention was a problem. However, the cost of this type of group-based lifestyle intervention was relatively low, so that such an intervention for this high-risk group may still be cost-effective.

Frailty in people with COPD, using the National Health and Nutrition Evaluation Survey dataset (2003-2006)

BACKGROUND Little is known about frailty in people with chronic obstructive pulmonary disease (COPD). The purposes of this study were to describe frailty, to identify, which demographic and clinical characteristics contributed to frailty, and to examine the relationship between frailty and health-related outcomes in people with COPD. METHODS This was a secondary cross-sectional study, using data from the National Health and Nutrition Evaluation Survey. The frailty index and outcome measures were derived primarily from survey responses. RESULTS The prevalence of frailty was 57.8%. Multivariate logistic regression showed that individuals with COPD who had self-reported shortness of breath and comorbid diabetes were more likely to be frail than those who did not. Frail people tended to have a greater number of disabilities. CONCLUSIONS The findings support the importance of frailty in the COPD population. Further study is needed to understand frailty in people with COPD, using objective measures for criteria of frailty.