00: Not in Universe
93: Extreme value
94: Less than once per week
96: Unable to do moderate/vigorous activity
98: Unknown-not ascertained
99: Unknown-don't know
VIG10FWK is a recoded variable created by the staff at the National Center for Health Statistics that draws upon the information in VIG10FTP (Frequency of vigorous activity 10+ minutes: Time period) and VIG10FNO (Frequency of vigorous activity 10+ minutes: Number of units) and reports the frequency of vigorous leisure-time physical activities in terms of a single time unit, times per week. Prior to 2020, the survey text for VIG10FNO and VIG10FTP inquired specifically about exercise that lasted at least 10 minutes. Beginning in 2020, the question did not include this provision.
Vigorous leisure-time activities are described in the survey question itself as activities that "cause heavy sweating or large increases in breathing or heart rate." The Field Representative's Manual provides examples of vigorous activities, although these examples were not routinely shared with respondents. These examples include fast walking, fast bicycling, jogging, strenuous swimming or sports play, vigorous aerobic dance, and strenuous gardening.
According to the Field Representative's Manuals for 2001-2018, the maximum frequency of each broad category of physical activity (moderate activity, vigorous activity, strengthening activities, and stretching activities) was topcoded at 4 times per day (or its equivalent in some other time unit). Beginning in 2020, individuals with values of 4 times per day (or its equivalent) or greater were coded as "93 - Extreme value."
For general discussion of how and why the NHIS collected information on adult physical activity for 1997 forward, see VIG10FNO.
VIG10FWK is available beginning in quarter 3 of 1997. For data on the frequency of respondents' vigorous activity in the first half of 1997, see VIG20FWK2.
The question wording for VIG10FTP and VIG10FNO, the variables used to create VIG10FWK, 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 frequency of vigorous activities reiterated the point that respondents were only to report leisure-time activities. From 1997 through 2003, interviewers asked, "How often do you do vigorous activities ..."; for 2004 forward, they asked, "How often do you do vigorous leisure-time physical activities ..." Thus, beginning in 2004, the question wording made explicit what had previously been implicit and had been specified in the introductory statement only.
A second minor change to the survey question was instituted in 1999, when the form added the following instruction to interviewers: "If necessary, prompt with: How many times per day, per week, per month, or per year do you do these activities?"
This prompt gave explicit directions to interviewers on how to proceed if respondents gave a vague answer such as "quite often," "once in a while," or "hardly ever." However, while these directions were missing from the survey questionnaire before 1999, they were included in the Field Representative's Manuals for 1997-200, which directed, "Prompt with 'How many times per day, per week, per month, or per year do you do these activities?'" Furthermore, the 1997-2000 Manuals stated, "Always probe for an exact number. If the Sample Adult reports a range or interval, assist the Sample Adult in making an estimate by probing. For example, you might ask 'Could you give me a more exact number?'"
A third change to the questionnaire text in 2020 removed the requirement that the respondent reports activities only lasting at least ten minutes.
VIG10FTP is asked after VIG10FNO, which reports the number to be used in conjunction with the time units reported in VIG10FTP. Prior to 2020, the question for VIG10FNO stated, "How often do you do vigorous leisure-time physical activities for at least 10 minutes that cause heavy sweating or large increases in breathing or heart rate?" Beginning in 2020, the question simply asks, "How often do you do vigorous-intensity leisure-time physical activities?" The question is preceded by a definition of vigorous intensity activities as those that "cause large increases in breathing or heart rate." MOD10FTP and MOD10FNO are used to construct MOD10FWK.
Finally, 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.
- 1998-2018: Sample adults age 18+.
- 2020: Sample adults age 18+.
- 1997-2018, 2020
- 1997-2018, 2020 : SAMPWEIGHT