You’ve probably promised yourself to get off the couch and get some exercise. But before you get up, you might be interested to know that new research suggests that not everyone will benefit from a good aerobic workout. The study appears in the Journal of Applied Physiology.

Many of us jog or swim or hit the gym in an attempt to keep fit, and to help ward off ailments like heart disease and diabetes. And aerobic exercise, which really gets your heart pumping and your blood flowing, is supposed to be the way to go. Because cardiovascular training generally increases what’s called the VO2 max, which is a measure of your ability to get oxygen to your hardworking muscles. The higher your VO2 max, the more fit you are. But in this study, scientists found that rigorous exercise does not boost everyone’s VO2 max. One in five participants improved less than 5 percent.

Their resistance was, in part, genetic—and the researchers were able to identify a set of genes that could predict who would not benefit from time on the Stairmaster. Imagine that tests show that, for you, exercise is a waste of time. Would you be disappointed? Or secretly delighted to get back on the couch?

—Karen Hopkin

[The above text is an exact transcript of this podcast.]