Overview of Topics
Physical activity - both leisure and non-leisure - has been included in the National Health Interview Survey for adults periodically since 1975. A brief description of NHIS physical activity questions follows.
- Questions about adult physical activity were first asked in the National Health Interview Survey (NHIS) in July-December, 1975 (Physical Fitness Supplement). NHIS respondents aged 20 years and over were asked a series of questions about their participation in exercise and sports activities and their self-perceptions of their physical activity levels relative to others the same age (6).
- Leisure-time physical activity questions were next asked in the 1984 NHIS Supplement on Aging (SOA) in a section entitled "Health Opinions." This section had a question about frequency of walking a mile or more, asked of adults aged 55 years and over. Although the question did not specify the reason for the walking (e.g., leisure, transportation, occupational, etc.), the context was consistent with leisure-time activity. Older adults in the 1984 SOA were also asked "Do you follow a REGULAR routine of physical exercise?" — a question that was repeated in the 1994 Supplement on Aging (SOA II).
- In the early 1980's the NHIS became the data source for tracking progress toward achieving many of the physical activity objectives outlined in the National Health Objectives for the Nation (10). Modeled after an approach used in the 1981 Canada Fitness Survey, the NHIS asked a detailed set of questions about leisure-time physical activity in 1985 and 1990 NHIS Health Promotion and Disease Prevention Supplements (25-27). These questions consisted of a list of specific leisure-time physical activities and included frequency, duration, and intensity questions for each activity mentioned. The questionnaire and documentation should be examined carefully to determine the universe for these questions as age and disability status determined which respondents were asked certain questions. Also asked in the 1985 and 1990 Health Promotion and Disease Prevention Supplements was a question on regularity of physical activity, "Do you exercise or play sports regularly?" and if yes, "For how long have you exercised or played sports regularly?"
- Questions for national surveillance of leisure-time physical activity continued through much of 1990's, with Health Promotion and Disease Prevention/Year 2000 Objectives Supplements in 1991, 1995, and 1998. The content of these questionnaires (renamed to Year 2000 Objectives supplements in 1995), was similar to the 1985 and 1990 versions, although there were some important differences that should be considered when analyzing data across years. For example, in the 1985 and 1990 supplements, some of the physical activity questions were limited to selected age groups. However, beginning in 1991, all adults aged 18 years and over were asked all of the physical activity questions.
- In 1997, as part of the National Health Interview Survey (core) questionnaire redesign, physical activity questions were included in the questionnaire for the first time. Questions used in Australia, Finland, and Canada, as well as studies of older adults and youth in the United States, influenced the development of the NHIS Sample Adult annual physical activity questions (28-31). Question wording and response options were modified for use in the NHIS Sample Adult questionnaire, tested in the Questionnaire Design Research Laboratory (QDRL) of CDC's National Center for Health Statistics, and included in a field pretest. Decisions concerning question phrasing, reference period, and response options were based on results of cognitive testing and debriefing of interviewers after the pretest. Consistency with other parts of the National Health Interview Survey questionnaire was also considered. The final NHIS core physical activity questions consisted of asking frequency and duration of usual leisure-time vigorous and light-moderate activities and frequency of strengthening activities.
- Additional physical activity questions have been added to the NHIS in supplements in selected years since 1997 and asked of the same adults who responded to the Sample Adult core questions.
- Selected leisure-time physical activity questions were included in the 1998 Healthy People 2000 Supplement and the 2000, 2005 and 2010 Cancer Supplements.
- A question about perceived physical activity level compared with activity level of other persons in the same age group was first asked in the NHIS in 1975. Respondents were asked "Would you say that you are physically more active, less active, or about as active as other persons your age?" Variations of this question were included in the NHIS in 1977, 1983, 1984, 1985, and 1990. Research has suggested that self-perception of physical activity compared with peers has reasonable validity (32, 33).
- A second indicator of perceived activity level, activity level compared with one year earlier, was first asked in the NHIS in the 1984 Supplement on Aging (SOA) for adults aged 55 years and over. The question was repeated in the 1994 Disability Follow-back Supplement (NHIS Phase II) and the Supplement on Aging Questionnaire (SOA II) and Adult's Questionnaire and asked of adults aged 70 years and over.
- In the 1984 Supplement on Aging, older adults were also asked about the perceived adequacy of their activity level: "Do you feel that you get as much exercise as you need, less than you need?"
- Transportation-related physical activity was first asked in the NHIS in the 2000 Sample Adult Cancer Control Supplement. Sample adults 18 years and over were asked "Do you usually walk or bike to work, school, or to do errands?"
- Questions about walking for transportation were also asked in the 2005 and 2010 Cancer Control supplements. The question wording differed across the three supplements.
- Occupation-related physical activity is an important component of physical activity for many U.S. adults. The 1985 and 1990 NHIS Health Promotion and Disease Prevention Supplements had questions to assess the amount of physical activity associated with a person's job or main daily activity.
- A 1988 Occupational Health Supplement had a few questions pertaining to physical activity on the job, although these questions were designed primarily to assess risk of repetitive motion injury.
- In 2000 and 2005, the NHIS Cancer Control Modules measured activity associated with one's job, although the frame of reference was expanded beyond occupation to include activities associated with any main daily activity to encompass adults not in the workforce, such as homemakers or retired individuals.
In addition to the measures of physical activity highlighted above, the NHIS has periodically included questions related to the broader context of the study of physical activity. Many of these have been included in the survey to measure progress toward specific national health promotion objectives. These additional physical-activity-related topics include:
- Knowledge of the health benefits of physical activity to strengthen heart and lungs (1985 and 1990) and to lose weight (1985 and 1990).
- Increases in physical activity behavior in order to lose weight (1985 and 1990) or in order to control weight (1991 and 1995).
- Medical advice received about physical activity generally (1993, 1994, 2000, 2005, 2006, and 2010), or specifically for high blood pressure (1985, 1990, 2003, and 2008), or for arthritis (2002, 2003, 2006, and 2009).
- Availability of/participation in employer-offered exercise facilities and programs (1991, 1993, and 1994).
- Family discussions about exercise or physical activity (1994).
- Participation in exercise classes (1995).
- Participation in alternative health exercises — yoga, tai chi, Qi Chong (2002, 2007 and 2008).
- Participate in exercises to treat a medical condition (2008).
- Sedentary behavior: sitting, watching TV, etc. (2000, 2005, 2010).