The median energy expenditure score, including sleeping, was 36.8 kcal·kg-1 for men and 36.5 kcal·kg-1 for women (mean: 39.9 kcal·kg-1 and 37.8 kcal·kg-1 respectively.) Using median body weights and energy scores, the total energy expenditure would be 2885 kcal and 2469 kcal for men and women respectively. The total number of hours per person resulting from the calculation of persons × Average Duration / 7515 is 24.01 hours per person.
The 88 activities were ranked in order of their contribution to energy expenditure for the entire sample. Sleeping or napping was the most common activity performed by the population, and averaged eight hours in the past 24-hour period, for both males and females. Sleeping or napping contributed 19% of the overall energy expenditure of the population.
In order to understand energy expenditure during waking hours only, all further descriptions of rankings will exclude sleeping as an activity. After exclusion of sleeping, the largest contributor (10.9%) to energy expenditure was "Driving a car" (Table ). The next largest contributors were "Job: office work" (9.2%), "Watching TV or a movie" (8.6%), "Taking care of children/baby" (8.4%), "Activities performed while sitting quietly" (5.8%), "Eating" (5.3%) and "Cleaning house, general" (3.9%). With the exception of "Taking care of children/baby" and "Cleaning house", the majority of the activities that account for 50 percent of the energy expenditure of the sample are predominantly very light in intensity. The 31 activities that account for 90 percent of the total energy expenditure, not including sleeping, are listed in Table . Ten of the 31 activities found on this list are occupational categories. It is notable that in the list representing the top 90% of energy expenditure, only four leisure-time activities are included (#s 22, 25, 29 and 31). Two of them, swimming and exercise/aerobics, are commonly measured by physical activity assessment tools. However, together these four activities make up less than 3% of the total waking energy expenditure in this sample.
Activities that account for 90% of energy expenditure in the United States, not including sleeping1.
A complete list that ranks all 88 activities can be found in the Appendix, together with identifications of the activities that were categorized as leisure and household. From the Appendix the total number of hours expended on each activity and each category of activity (moderate intensity, vigorous intensity, leisure, job, etc.) can be calculated. Overall, activities that are considered leisure time physical activity made up only approximately 5% of the total energy expenditure. On any given day, approximately 86% of the population engaged in no leisure physical activities as defined here. In contrast, activities that are household-related made up 27% of the total energy expenditure for this sample. Approximately another one-fourth of energy expenditure was derived from employment. Low-intensity jobs (MET < 3.0) made up 12.7% of all energy expenditure, moderate-intensity jobs (3–6 MET) contributed 11.4%, and high-intensity jobs (MET > 6.0) contributed only 1.8% to total energy expenditure. Activities of any type (leisure, work, household or other) that represented moderate-intensity physical activity (3–6 METs) represented 33.6% (most of which were at the lower end of the range), while high-intensity physical activity (MET > 6) represented 5.5 % of total energy expenditure. On average, the population spent 2 hrs 50 minutes "Watching TV/movies" and 1 hr 25 minutes on "Activites performed while sitting quietly".
Activities by gender
In the data-based approach to activity assessment used here, all types of activities are assessed, including activities that are not often thought of as important energy expenditure contributors due to their lower intensity level (e.g. cleaning house). Using this approach, the median energy expenditure scores for men and women were approximately equivalent, 36.8 vs. 36.5 kcal·kg-1 for men and women respectively. Mean scores for males and females were 39.9 and 37.8 kcal·kg-1 respectively, suggesting that there is a subset of men who expend substantially more energy than women. These results suggest that independent of the difference in body weight between men and women, the per-kg energy expenditure of men and women is similar.
The types of activities contributing to these expenditure levels are shown in Table , by gender, for activities contributing to the top 90% of energy expenditure. Ninety percent of men's energy expenditure can be described by thirty-one activities, while women's energy expenditure can be described by twenty-five. The two lists of activities in Table demonstrate the difference in time and energy expenditure between males and females in their typical activities during the day. There are five activities mentioned on these two lists that were not present on the previous list for the entire sample. The energy expenditure for leisure time physical activity was slightly higher for males (6.5 %) than females (4.2 %) (data not shown). Household related activities accounted for 20.1 and 33.3 % of the energy expenditure for males and females, respectively. Only 16.4% of males and 11.3% of females reported performing at least one occurrence of leisure time physical activity during the previous 24-hour period.
Activities accounting for 90% of energy expenditure in the United States for males and females1.
Activities by ethnic Group
The NHAPS study included subjects from five ethnic groups across the country. While activities are described below for each ethnic group, these representations of usual activity patterns should be interpreted with caution for the Asian and Other groups, due to small sample size.
Lists of activities contributing to daily energy expenditure were calculated for each ethnic group (data not shown). Each list uncovered additional activities that were not seen on the overall list. The list for Whites was similar to the overall list of activities except for the addition of two more activities: "Moving, packing items" and "Sports: Golf". The list for African-Americans included the additional activity of "Caring for another person". The list for Hispanics included the additional activity of "Household chores, light cleaning". The list for Asians included two additional activities: "Sports: Golf" and "Playing with children, baby". The list for Others included two additional activities: "Job: Painting" and "Home projects".
The number of activities needed to capture 90% of the energy expenditure varied by ethnic group, with the most number of activities used to describe the White group and the least number of activities used to describe the African-American group (Table ). The White group's percentages for both leisure time physical activities and household-related energy expenditure were the highest among the ethnic groups. African-Americans had the lowest percentage of leisure-time physical activity and Asians had the lowest percentage of household-related activities. The African-American group also had the highest percentage of individuals who did not report any leisure time physical activity in the past 24-hour period. Scores for Hispanics were intermediate between the White and African American group.
Physical Activity Patterns of each Ethnic Group in the NHAPS Survey4.
Past studies have indicated that minority women often have lower physical activity levels than other subgroups [9
]. A further division of ethnic group by gender was used to examine differences in activity patterns between men and women, by ethnic group. The mean Scores, and percentages for leisure time physical activity and household related activities for White, African-American, Hispanic and Asian males and females are displayed in Table . In all ethnic groups except Asians, there is a pronounced difference between the two genders in the amount of energy expenditure attributed to household related activities, and to leisure time activities. In each ethnic group, the percentage of energy expended on household related activities was higher for females than males. The percentage of energy expenditure due to leisure time physical activities was higher for males in each ethnic group except for Asians. As in previous research, African-American women were found to have the lowest expenditure on leisure time physical activities. They do perform, however, a much larger percentage of household related activities than their male counterparts.
Race and Gender Patterns of Physical Activity in the NHAPS Study3.
Each ethnic and gender subgroup also provided additional activities that were not on the overall activity list or their respective gender activity list. For White males, there were four activities that did not appear on the overall list: "Sports: Golf", "Car maintenance, repair", "Yardwork – hard: e.g. chopping firewood..." and "Job: Feeding/ Working with livestock." White females include three more additional activities that were not on the overall list: "Home projects (sewing...)", "Moving, packing items" and "Washing dishes/loading dishwasher". The list created for African-American males included three activities that were not on either the overall or male activity list. These were "Caring for another person", "Sports: soccer", and "Sports: Basketball". African-American females also included the activities of "Caring for another person" and "Exercise, aerobics". The list for Hispanic males included two activities that were not on either the overall or male activity list: "Sports: Basketball" and "Sports: Soccer." Hispanic females also included two additional activities that were not on the list generated for females: "Dancing/ Heavy Partying..." and "Playing outdoors with others". For Asian males, there were three activities that did not show up on the list generated for all males: "Cleaning kitchen (sweeping)", "Playing with children", and "Other moderate recreational sports." The list for Asian females included two activities that were not on the overall list: "Sports: Golf" and "Home projects (sewing...)". The activities of "Sports: Golf" and "Fishing and Hunting" were also on the Asian female list but not on the list generated for all females.
Activities by age
The results in Table demonstrate a decreasing trend in the amount of energy expended on leisure time physical activities with increasing age. This is paralleled by an increasing amount of energy being spent on household related activities with increasing age. Mean scores for the study population peaked in the age group of 35–44 years and dropped off in successive years. Each age group included activities different from those found in the overall list. The lists for the older age groups (65–74 and 75 + years) had the largest number of different activities. The activity list for the age group of 65–74 years included six activities that were not on the overall list: "Sports: Golf", "Yardwork – hard: e.g. chopping firewood...", "Home projects (sewing...)", "Game, board or cards...", "Petcare: walking..." and "Household chores, light cleaning." The activity list for the age group of 75 years and over included six activities that were not on the overall list as well: "Painting walls", "Volunteer work, unspecified", "Game, board or cards...", "Home projects (sewing...)", "Household chores, light cleaning" and "Washing dishes/ loading dishwasher."
Physical Activity Patterns of each Age Group in the NHAPS Survey1.
Activities by region
Physical activity patterns were also evaluated by region (Table ). Energy expenditure for leisure time physical activity was the greatest for the Pacific (California, Nevada, Arizona, Hawaii), New England (Maine, New Hampshire, Vermont, Massachusetts, Connecticut and Rhode Island) and Mountain (Washington, Oregon, Idaho, Alaska) regions. The Central region (Nebraska, Kansas, Iowa, and Missouri) had the lowest energy expenditure for leisure time physical activity. The percentage of individuals who didn't mention any leisure time physical activity in the past 24 hour period was lowest in the Pacific and Mountain regions, and highest in the Central region. The South Central (New Mexico, Texas, Oklahoma, Arkansas, and Louisiana) and Central regions had the greatest energy expenditure spent on household related activities, while the North Central region (Montana, Wyoming, Utah, Colorado, North Dakota, and South Dakota) had the lowest.
Physical Activity Patterns of each EPA Region in the NHAPS Survey1.
As individuals were surveyed throughout the year, we also evaluated whether there were any seasonal differences in activity (data not shown). As expected, a larger percentage of energy expenditure on leisure time physical activities was seen in the warmer seasons: summer (6.8%), spring (5.3%) and fall (5.3 %) than in the winter (3.9%) season. This is similar to the findings from the Surgeon General's report that individuals are substantially more often physically inactive in the winter months than the summer months [1