Current U.S. physical activity (PA) guidelines recommend at least 30 min of moderate-intensity PA on most, preferably all, days of the week for overall health benefits (17). Regularly performed aerobic PA can increase fitness and reduce the risk of death from cardiovascular disease, various cancers, and complications of diabetes (22). Despite these public health recommendations, national data suggest that in 2003, only 45.9% of the population engaged in regular activity that met the public health recommendations (4). Moreover, a large proportion of the population (39%) reported some activity, but not in combinations of frequency, duration, and intensity equal to or exceeding recommendations (11).
Epidemiological research suggests that the total amount of energy expended in PA has an important bearing on mortality rates (18). The rationale for recommending activity on most days of the week is attributable to evidence from early intervention studies that involved exercise training over multiple days (7,21). The literature suggests that certain risk factors such as blood pressure (14) and depressive symptoms (6) respond more favorably to more frequent bouts of aerobic PA. However, few studies have been able to isolate the effect of physical activity frequency for all-cause mortality (9).
Weekend warrior is a colloquial term used to describe people who tend to compress their weekly activity into long durations (i.e., 4-h hike, 3 h of yard work, or an afternoon of basketball) on 1 or 2 d·wk−1. Anecdotal evidence suggests that weekend warriors are common in the U.S. population and that they may be at risk of future injury (20). Only recently, in a paper by Lee et al. (8), has the dose of the weekend warrior pattern been examined in relation to health outcomes. To date, there is insufficient evidence that an irregular PA pattern with an energy expenditure comparable with the minimum PA recommendations is associated with overall health benefits. Weekend warriors are of interest to public health because they may reap some health benefits by being physically active, but they may be at a higher risk for chronic disease than those who are regularly active. In addition, weekend warriors may be receptive to increasing their PA frequency to improve their cardiovascular health.
Little is known about the characteristics of adults who engage in irregular patterns of PA at volumes that may be equivalent to recommended levels. The purpose of this paper is to describe the prevalence, estimated energy expenditure, and types of activities performed by adults (≥18 yr) who engage in irregular patterns of PA (1-2 d·wk−1) with a total time of ≥ 150 min·wk−1 spent in moderate- and vigorous-intensity activity (i.e., weekend warriors).
Data for this study were obtained from the Behavioral Risk Factor Surveillance System (BRFSS) and the National Health and Nutrition Examination Survey (NHANES). These two surveys have been described elsewhere (5,13) and are briefly summarized below. For the purpose of our study, two complementary data sources were used to allow a more complete description of weekend warriors.
The BRFSS is a state-based, random-digit-dialed telephone survey of health risk behaviors in the civilian, noninstitutionalized population in the United States. Data are collected each year by all 50 states and the District of Columbia. Self-reported data on moderate- and vigorous-intensity leisure-time, household, and transportation-related PA are reported in odd-numbered years. In 2003, the sample size for 50 states and the District of Columbia was 264,684 people, and the median response rate for those states was 53.2%. In 2003, PA (http://www.cdc.gov/brfss) was assessed from responses to six questions about the frequency and duration of moderate- and vigorous-intensity nonoccupational physical activity. Respondents were classified as weekend warriors if their summed frequencies of moderate- and/or vigorous-intensity PA was 1 or 2 d and if their summed durations totaled ≥ 150 min·wk−1 of moderate- and vigorous-intensity PA. To estimate weekly energy expenditure, moderate-intensity activities were assigned a metabolic equivalent (MET) value of 3.0, and vigorous-intensity activities were assigned 6.0 METs according to the compendium of physical activities (1). MET-minutes per week were calculated by multiplying the MET value by the minutes per week of activity and summing the moderate-intensity and vigorous-intensity MET-minutes per week.
Because the 2003 BRFSS does not include questions on specific types of physical activities performed, NHANES data were analyzed as part of this study to provide additional descriptive details about PA patterns among weekend warriors. The NHANES is an in-person health interview and examination that collects information on health conditions and risk factors. Data are collected in 2-yr cycles from the U.S. civilian, noninstitutionalized population. Survey questions about PA collected in three cycles (1999-2000, 2001-2002, and 2003-2004) were comparable in wording and methods and, therefore, were combined to increase the sample size of adults aged ≥ 18 yr (N = 31,126). To examine types of activities reported, we analyzed survey data questions about transportation, household, sports, and leisure-time PA. Because the sample size for each specific activity was small, we created two categories: household/transportation-related activities, and sports/exercise-related activities.
Data from the 1999-2004 NHANES (http://www.cdc.gov/nchs/guidelines1.pdf) were analyzed to identify weekend warriors, using responses to 16 PA questions on transportation, household, sports, and leisure-time activities. In 1999-2000, the overall response rate for those interviewed was 81.9%. In 2001-2002, the overall response rate for those interviewed was 83.9%. In 2003-2004, the overall response rate for those interviewed was 79.3%. Transportation-related PA was defined as walking or bicycling to work, school, or to do errands. Respondents were asked about participation, frequency (i.e., how many times per day, per week, or per month), and duration (i.e., how many minutes or hours per day) of walking and bicycling. The NHANES survey also included three questions about participation, frequency, and duration per session of moderate-intensity household-related PA such as gardening, yard work, or heavy cleaning. The question on participation in vigorous-intensity leisure-time PA was, "Over the past 30 d, did [you] do any vigorous activities for at least 10 min that caused heavy sweating, or large increases in breathing or heart rate?" Respondents who answered "yes" were then asked to report on the specific sports and exercises from a list of 23 possible activities (e.g., running, basketball, aerobic exercise). Respondents were then asked how often and for how long they performed each activity. Participation in moderate-intensity leisure-time PA for at least 10 min per occasion, during the past 30 d, was evaluated in a similar manner. Respondents were asked to report on the specific sports and exercises from a list of 33 possible activities (e.g., hiking, walking, gardening, yard work, or martial arts). Using the aforementioned questions, respondents were classified as weekend warriors if they answered "yes" to any of the questions and if they reported participating in four to eight sessions of total activity within the 30 d before the interview, for a total of ≥600 min per month. We considered this to be equivalent to one to two sessions per week and ≥ 150 min·wk−1 of moderate- and vigorous-intensity activity. To determine participation in types of activities, data from questions about household and transportation-related activities and gardening and yard work that were reported as leisure-time physical activities were combined into household and transportation-related activities (e.g., gardening, yard work, heavy cleaning, walking or bicycling for transportation), and data from specific sports for either vigorous- or moderate-intensity activities (e.g., jogging, walking) were grouped as sports and exercise-related activities.
To demonstrate the comparability of the surveys, sample characteristics for weekend warriors were described by sex, age, race/ethnicity, and education level for the BRFSS and the NHANES data as sample sizes and weighted percents. Overall and sex-specific prevalences of weekend warriors were reported from the BRFSS and the NHANES data. Estimates of energy expenditure (median and 25th and 75th percentiles) were based on MET-minutes per week and were calculated using the BRFSS data. Participation in activity domains were reported for weekend warriors overall and by sex from the NHANES data. Statistical significance of findings was interpreted from degree of overlap in 95% confident intervals. All analyses were conducted using SUDAAN version 9.0 (Research Triangle Institute, Research Triangle Park, NC, 2004) to account for the complex sample design of each of the two surveys.
The demographic characteristics of weekend warriors tended to vary by age, race/ethnicity, and education level (Table 1). Sample age distributions varied from 12.3% in the BRFSS for those aged 18-29 to 19.4% in the NHANES for those aged 18-29. Weekend warriors were primarily non-Hispanic white (64.7% in BRFSS; 74.7% in NHANES). The distribution of demographic characteristics of weekend warriors in the BRFSS was similar to that in the NHANES.
Overall, approximately 1% of adults were classified as weekend warriors according to BRFSS data, and approximately 3% were weekend warriors according to NHANES data (Fig. 1). In both surveys, more men than women were classified as weekend warriors. Among weekend warriors, the distribution of sex by age is shown in Figure 2 from the BRFSS. The prevalence of this pattern is highest among those aged 45-64 and is lowest among those aged 18-24.
From the BRFSS, the estimated median energy expenditure for those classified as weekend warriors was 1079 MET·min·wk−1. The estimated energy expenditure reported by weekend warriors did not vary by sex (Table 2).
From the NHANES analyses, household/transportation or sports/exercise activities were frequently reported by weekend warriors (Fig. 3). Approximately 81% of weekend warriors engaged in purposeful activities such as gardening, yard work, and walking and/or bicycling for transportation. Approximately 65% of weekend warriors participated in sports and exercise. A greater proportion of men than women participated in sports/exercise-related activities (P < 0.001).
This study suggests that approximately 1-3% of U.S. adults may be weekend warriors-adults who participate in PA patterns that may be equivalent to recommended levels in terms of total volume but that are accomplished on 1 or 2 d·wk−1. The national prevalence was less than expected in light of anecdotal evidence suggesting that occupational constraints and lack of leisure time lead to difficulty in scheduling physical activity during the workday (12,19). According to BRFSS data, this pattern of activity is highest among those aged 45-64-an age group that often experiences time constraints from having to care for children as well as parents, in addition to large occupational time requirements.
It cannot be determined from these data whether the same volume of PA achieved through infrequent bouts (1-2 d·wk−1) or regular activity (≥ 5 d·wk−1) has different health effects. The estimated energy expenditure for those classified as weekend warriors may be sufficient to confer some of the health benefits of regular PA. We found that weekend warriors had an estimated median energy expenditure of 1079 MET·min·wk−1, and Brown and Miller (3) suggest that at least 525 MET·min·wk−1 are needed to meet PA recommendations for health (e.g., 30 min of moderate intensity on five or more days per week). Lee et al. (8)found that healthy men who were physically active only 1-2 d·wk−1 with an energy expenditure of 1000 kcal·wk−1 (equivalent to ≥ 150 min·wk−1 of moderate-intensity PA) had reduced risk of all-cause mortality compared with sedentary men. However, the same study found that men with any risk factors for chronic disease who engaged in this PA pattern did not have a reduced risk of all-cause mortality, whereas those whose energy expenditure met the recommendations had a reduced risk of mortality.
In our study, we found that a large proportion of weekend warriors participate in household/transportation-related activities and sports/exercise-related activities. Because studies have shown that household activities such as home repair and gardening are associated with health benefits (10,15), and because these activities are often performed in intermittent bouts and on weekends, future research comparing the conditioning response and health effects gained from household versus leisure-time activity is needed. One study found that engaging in two consecutive days of walking or running as endurance training for 75 min·d−1 (e.g., weekend warriors) compared with 30 min·d−1 of similar activities performed on 5 d at the same intensity produces a similar training effect on V˙O2max (12). Although not significant, the cumulative training effect was slightly lower for those who engaged in more frequent bouts of endurance training for a shorter duration than it was for the weekend warriors. Future research is needed to compare the health benefits gained by participation in activities of low intensity (e.g., golf) (16) versus more strenuous activities (e.g., basketball, yard work) (2) among weekend warriors.
The results of this analysis are subject to several limitations. First, data from both the BRFSS and NHANES are self-reported, and physical activity levels may be underestimated. Additionally, these datasets were not specifically designed to study weekend warrior behavior. Second, the survey questions did not specifically ask respondents to report the actual day(s) of the week they engaged in activity (i.e., weekday or weekend); therefore, we conducted the analysis on the basis of the frequency of activity (i.e., 1-2 d·wk−1; four to eight sessions per month), and we cannot verify whether activities were performed on the weekend, or whether multiple activities were performed on the same day or different days. Moreover, there were different sample frames in the questions used (i.e., BRFSS measured times in the past week, and NHANES measured times in the past 30 d), which may introduce bias when comparing the surveys. Third, the NHANES sample was small, limiting the subgroup analyses that could be performed. Furthermore, NHANES asked respondents to report on 23 questions about sports and exercise activities, possibly leading to reporting of more PA. Fourth, our computation of MET-minutes per week was based on the absolute MET-value activity codes in the compendium of physical activities (1), and we classified total energy expenditure for moderate- and vigorous-intensity at the low end of each intensity range without adjusting for respondents' age. Because many activities can be performed at multiple intensities, respondents could have reported time spent in moderate-intensity activity when light-intensity activity had been performed.
Important strengths of this study include the use of two national surveys with somewhat similar questions on PA, allowing for comparison of national estimates between surveys and a more detailed descriptive analysis of weekend warriors than would have been possible using only one survey. Specifically, the NHANES included questions on specific types of activities; this was not part of the BRFSS survey.
In summary, roughly 1-3% of the U.S. population engages in irregular patterns of PA (i.e., 1-2 d·wk−1) that approximate PA recommendations in terms of volume of activity, and more men than women have this activity pattern. Among men and women, the distribution of this pattern is highest among those aged 45-64. The types of PA reported by weekend warriors include household and transportation activities, such as gardening, yard work, and sports, or exercise. More research is needed to help further describe the activity patterns and trends in these individuals.
The findings and conclusions in this report are those of the authors and do not necessarily represent the views of CDC. The results of the present study do not constitute endorsement of the product by the authors or ACSM.
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Keywords:©2007The American College of Sports Medicine
EXERCISE; SPORTS; PHYSICAL FITNESS; PHYSICAL ACTIVITY