This is a solid look at a study of the effects of exercise at different intensities and durations in obese people who were sedentary at the start of the study. The explanation of what the researchers did and what they found is careful, and the take-home messages are reasonable. The story didn’t, however, acknowledge that subjects in the higher-intensity exercise group had a higher rate of injuries that were not trivial. In addition, a bit more discussion of how cost can affect the availability of exercise would have been welcome.
Many overweight, out-of-shape people want to begin exercise programs and are looking for guidance on how much is enough. This story highlights findings showing that exercising a bit harder and longer leads to a modest improvement in one risk factor for heart disease compared with a less intense regimen. While that’s one way to look at these results, you might also say that the results vindicate those who do the bare minimum that the government recommends. In this study, those who walked slowest, for the shortest amount of time, lost the same amount of bodyweight, the same number of inches from their waists, and had fewer injuries than those who exercised more vigorously. That might be a more relevant and inclusive message for a nation where getting no exercise at all is far too common.
Fitting exercise time into a life can be tricky if you are in poverty, working two jobs, or don’t have a safe neighborhood. The story delivers an implicit acknowledgment of such concerns in the first line when it says, “Some people — who are they? — have no problem fitting regular aerobic exercise into their lives.” But that’s not quite enough for a satisfactory rating here. The study involved “supervised” training sessions, which we assume means with some kind of trainer. How much would it cost to hire someone like that or join a gym that offers exercise equipment? A quick statement about those costs would’ve earned the story a pass here.
The story (complete with table) did a fair job of balancing a digestible message with the caveats of research. It tells us that all the exercise groups lost about 2 inches off their waistline and about 5% to 6% of their bodyweight. Since average people don’t really think about weight loss in terms of “percentage bodyweight,” however, it would have been better for the story to tell us how much participants weighed at the start of the study and how much weight each group lost in pounds.
And while the story suggests that brisker walking gives more benefit by improving glucose tolerance, it expressly cautions that this change may not be meaningful to patients: “It’s unclear whether the 9 percent improvement seen will be enough to cut their risk of heart disease, though.” That’s a useful distinction.
The high-intensity exercisers in this study had higher rates of musculoskeletal issues (cramping, strains, bone breaks — several of which required hospitalization) than other groups. Adverse effects caused more people to drop out of the study in the high-intensity group compared with the other groups. The story did not mention this.
The story thoroughly describes the study in broad strokes, although it could have clarified for readers that this was a randomized study — a strong type of design that reduces the risk of bias.
We also like the way the story helps readers parse the Goldilocks style levels of low, moderate and high intensity exercise. And it clarifies that all participants were told to keep a food diary and to eat a healthful diet that would keep their calorie intake constant. That’s valuable context, since changes in diet between the groups could have affected many of these outcomes.
But what’s not clear — either in this story or in the original study — is how much the “healthful diet” prescribed during the study differed from what the participants were eating at the start of the study, and how much that change contributed to the benefits that were seen in all of the exercise groups. The story focuses on exercise being the critical factor producing the benefits, but a better diet could arguably have contributed to improvements in many of these outcomes. We wish the story had inspected that aspect of the study more closely, but we won’t penalize it for not doing so.
There was no disease mongering.
The story quotes an exercise expert who was not affiliated with the study. He provides some useful context on the value of strength training.
The story discusses the benefits of aerobic exercise on obesity and cardiovascular outcomes. It also mentions strength training, which we’ll consider good enough for a satisfactory rating. A mention of other approaches — calorie-restricted diet, medications, even surgery in some cases — would also have earned the story a pass on this one.
[Editor’s note: this story was originally graded Not Satisfactory on this criterion, but has been change to Satisfactory for the reasons discussed below in the comments.]
Walking and other forms of exercise are widely available for most. As noted above, however, some mention of the cost of a gym membership would have been helpful in a story like this.
The story reminds readers that these results build on material already explored and reported. It establishes that the current study was investigating potential benefits — beyond saving time via a shorter workout — of higher exercise intensity.
Direct quotes from both the study author and an exercise expert show original reporting beyond any news release.