Vigorous Exercise and Obesity
To play an AIDS victim in the film The Dallas Buyer's Club, actor Matthew McConaughey lost 40 pounds. How? He consumed only chicken, Diet Coke, and egg whites for six months.1 What might he have done if he had to gain a massive amount of weight instead?
A new study provides a shocking clue as to how to pile on the pounds. The study, just published in The Mayo Clinic Proceedings, tracked a representative sample of 2600 adults aged 20-74 for two years, observing their diets, sleep habits, weight, and exercise patterns.2 The study found that the average obese woman exercises vigorously only one hour a year! Obese men do slightly better at 3.6 hours annually. This figure was verified by having participants measure their activities using a device called an accelerometer.
For the purposes of the study, vigorous exercise was defined as intense aerobic, fat-burning activities such as jogging, running up a flight of stairs, playing tennis or basketball, swimming laps, or jumping rope.3 Critics of the study point out that obese people don't normally engage in such activities anyway, and the study didn't count more moderate activities such as walking. Nevertheless, it's the vigorous aerobic activities that promote significant weight loss, and getting only an hour of such exercise annually certainly isn't enough. As we've noted before, the US Department of Health and Human Services recommends that we get at least 75 minutes a week of vigorous exercise, plus two 30-minute sessions of weight-bearing exercise. Or, as an alternative, 150 minutes of moderate exercise will do the trick.4
Women of average weight get ten times as much vigorous exercise as do their obese counterparts. While that sounds significant enough to make a huge difference, the fact is, multiply one hour times ten and it adds up to only ten hours a year, which still leaves a breathtaking gap between the amount of exercise required to stay fit, and the reality.
Study director Edward Archer of the University of South Carolina commented, "We knew we lived in an incredibly sedentary nation, but didn't know the exact extent until we measured it. People are truly living life chair to chair." He adds, "I think [most people are] living the typical life. They drive their children to school, they sit at a desk all day long, they may play some video games and they go to sleep."
Archer explains that the problem with such dramatic levels of inactivity isn't simply that people take in more calories than they burn, leading to weight gain, but that as the body becomes increasingly inactive, it handles calories differently, making weight gain increasingly inevitable. A catch-22 situation develops, where the inactive person becomes increasingly obese and the more obese he or she becomes, the more difficult and painful it becomes to exercise.
"Inactivity is both the cause and the effect of obesity," Archer says.5 Those critics who fault the study for not measuring moderate activity as well as vigorous exercise should take note that Archer did measure the "physical activity ratio," or PAR, of all participants. The physical activity ratio shows the energy cost of any activity.6 For perspective, activities like eating, watching television, and lying down have a PAR of 1 to 1.4. Activities like sewing or typing have a PAR between 1.4 and 1.8. According to Archer, a completely bedridden person will have an average daily physical activity ratio of 1.35. The average person in the study had a physical activity ratio of 1.5, with obese individuals below that level. By comparison, an athlete or hunter-gatherer will have a physical activity ratio of around 2.0. Translated, this means that the participants had energy outputs far closer to bedridden individuals than to people in excellent shape. And that fact applies to the average person--not just to the obese. Certainly, long periods of inactivity can drive the average individual over the edge into obesity.
As Jon Barron has written many times, one out of every three adults in the US is obese, and two out of every three are overweight. Obviously, simply knowing that we need to exercise in order to reverse the trend isn't doing the trick for the masses. Archer stresses the fact that people don't exercise because they imagine they'll have to lift weights or jog, and those types of activities seem too challenging. But he notes that taking small measures like walking instead of driving the car, or standing rather than sitting, will start to make a difference.
Solving the problem clearly isn't a simple matter. For more on the obesity conundrum and what can be done about it, see Jon Barron's article, "Obesity: You're Still in Charge."
- 1. Gusmeroli, Danielle. "Losing three stone for Dallas Buyer's Club made me smarter, insists Matthew McConaughey." 18 February 2014. Daily Mail. 24 February 2014. http://www.dailymail.co.uk/tvshowbiz/article-2561875/Matthew-McConaughey-says-losing-three-stone-Dallas-Buyers-Club-smarter.html
- 2. Dotinga, Randy. "Average Obese Woman Gets 1 Hour of Exercise a Year." 20 February 2014. WebMD. 24 Februaray 2014. http://www.webmd.com/fitness-exercise/news/20140220/average-obese-woman-gets-just-1-hour-of-exercise-a-year-study
- 3. Castillo, Michelle. "Obese women only get one hour of vigorous exercise a year: Study." 21 February 2014. CBS News. 24 February 2014. http://www.cbsnews.com/news/obese-women-only-get-one-hour-of-vigorous-exercise-a-year-study
- 4. "Obese women only get an average of 1 hour of exercise a year, study says." 21 February 2014. Fox News. 24 February 2014. http://www.foxnews.com/health/2014/02/21/obese-women-only-get-average-1-hour-exercise-year-study-says
- 5. "Validation of a Protocol for Measuring Energy Requirements for the US Population." Mayo Proceedings. 25 February 2014. http://www.youtube.com/watch?v=gNX0124qY90&list=PLcFM5N99WwbmOgs_V0DxWBAS40LWPgPxd&feature=c4-overview-vl
- 6. http://www.ucl.ac.uk/~ucbcdab/enbalance/definitions.htm#PAR