Codes and Frequencies
For sample adults who do moderate physical activities (MOD10FTP), MOD10DTP reports the time period (minutes or hours) during which they engaged in light or moderate leisure-time physical activities. Prior to 2020, the survey text inquired specifically about exercise that lasted at least 10 minutes. This variable must be interpreted in conjunction with the variable MOD10DNO, which reports the duration in number of units corresponding to the time period reported in MOD10DTP. For example, a respondent who walks for 30 minutes would have a MOD10DNO value of 30 and a MOD10DTP value of 1 (which is the code for "minutes").
MOD10DMIN, a recoded variable created by the staff at the National Center for Health Statistics, draws upon the information in MOD10DNO and MOD10DTP and reports the duration of light or moderate physical activity in a standardized unit of time, minutes.
Light or moderate activities are described in the survey questionnaire as activities that "cause only light sweating or a slight to moderate increase in breathing or heart rate." The Field Representative's Manual provides examples of light or moderate leisure-time physical activities, although these examples were not routinely shared with respondents. These examples include leisurely walking or bicycling, slow swimming or dancing, and simple gardening.
Beginning in 2020, individuals with a duration value (ascertained through combining MOD10DNO and MOD10DTP) equivalent to 720 minutes or 12 hours or more were coded as "3 - Extreme value." Additionally, the 2020 Survey Description notes that "an instrument error in 2020 allowed for entries of more than 24 hours in duration" (85). These entries were recoded to "Extreme value."
For further discussion of data collection on leisure-time physical activity in general for 1997 forward, see VIG10FNO (Frequency of vigorous activity 10+ minutes: Number of units).
MOD10DTP is available beginning in quarter 3 of 1997. For data on the duration of respondents' light or moderate activity in the first half of 1997, see MOD20DTP2.
The question wording for MOD10DTP changed slightly in 2004.
For all years from 1997 forward, the survey section on physical activity began with the statement, "The next questions are about physical activities (exercise, sports, physically active hobbies ...) that you may do in your leisure time." Beginning in 2004, the question about duration of light or moderate activities reiterated the point that respondents were only to report leisure-time activities. From 1997 through 2003, interviewers asked, "About how long do you do these light or moderate activities each time"; for 2004 forward, they asked, "About how long do you do these light or moderate leisure-time physical activities each time?" Thus, beginning in 2004, the question wording made explicit what had previously been implicit and had been specified in the introductory statement only.
Prior to 2020, the series of questions about moderate physical activity included that the exercise last at least 10 minutes. Beginning in 2020, people who report engaging in moderate physical exercise in MOD10FTP are in universe for MOD10DNO, regardless of whether they typically engaged in such exercise for at least 10 minutes.
Additionally, while the basic meaning of this variable is completely comparable over time, major questionnaire changes introduced in 2019 may affect comparability with earlier years. The NHIS questionnaire was substantially redesigned in 2019 to introduce a different data collection structure and new content. For more information on changes in terminology, universes, and data collection methods beginning in 2019, please see the user note.
- 1997: Sample adults age 18+ in quarters 3 and 4 who participate in moderate activities for at least 10 minutes.
- 1998-2018: Sample adults age 18+ who participate in moderate activities for at least 10 minutes.
- 2020: Sample adults age 18+ who do moderate physical activities (MOD10FTP).
- 1997-2018, 2020
- 1997-2018, 2020 : SAMPWEIGHT