It is at the top of many people's New Year's resolutions. It is what people vow to do even when the New Year's celebration is a foggy memory. Get more exercise! So who really does get more exercise?
I was especially happy to find the study I'm going to tell you about because exercise is something that comes up not infrequently in the comments posted to this blog. And though I comment on the comments only occasionally, I always read them and stay alert for relevant research that addresses the questions that come up.
The study was based on data collected in the year 2000 from a national sample of more than 13,000 Americans, ages 18 to 64. The study was a cross-sectional one (data were collected at just one point in time) so we need to be cautious in interpreting any marital status differences. A better study would follow the same people as they stay single or marry or divorce or remarry, and see how their patterns of exercise change.
The participants were asked if they engaged in each of 16 different "exercises, sports, or physically active hobbies" or any other type of exercise not listed, during the previous 2 week period. They were also asked how many minutes they spent at each. Adding all of the time spent exercising added up to the averages that are listed below. (The first number is the number of hours and the next two are the number of minutes; so 8:03 is 8 hours and 3 minutes over the course of 2 weeks.)
Time Spent Exercising
8:03 always single
4:47 currently married
5:25 always single
4:00 currently married
Men get more exercise than women in every marital status category. People who have always been single - including both men and women - get more exercise than people in any other marital status category. The currently married get the least exercise among the men, and next-to-least among the women.
Statistical analyses control for age, so that does not account for the differences.
What's with the married men getting so little exercise relative to all of the other men? I bet you can anticipate the authors' guess about this before they analyzed the data: The married men work harder at their jobs and some of them are spending time as parents, too. The authors tested that, in analyses that controlled for the men's parental status and the number of hours they spent at work. Guess what? Married men still got less exercise than single men.
The authors also tested the prediction that marriage and family status would put a bigger dent in women's exercise time than men's. Again, this study does not allow for an ideal test of that hypothesis, but even in a suggestive way, the data are not cooperating. For men, the difference in exercise time between the always-single and the currently married is a whopping 3 hours and 16 minutes for the 2-week period. For women, it is just 1 hour and 25 minutes.
Here's another interesting (though just suggestive) nugget from the authors:
"From the mid-1970s to the mid-1990s, during the period when adult women's labor force participation increased, women's participation in exercise increased dramatically."
OK, readers, go at it: What do these findings really mean?
Nomaguchi, K. M., & Bianchi, S. M. (2004). Exercise time: Gender differences in the effects of marriage, parenthood, and employment. Journal of Marriage and Family, 66, 413-430.