On the whole, working out is good for people. But when digging into the numbers, researchers have found a wide range of responses to regimens: Some people reap tremendous benefits, while others actually regress in their fitness, reports the New York Times. But new research suggests that these so-called "non-responders" just need to switch up their game plan and find something their bodies respond to instead of sweating over lack of progress. Reporting in the journal PLOS ONE, researchers note a simple at-home test that can help people learn if they're getting anything out of a particular workout: Measure your fitness level before starting a new fitness regimen by quickly stepping onto and off a box or climbing stairs, then check your pulse to get a baseline number. After a month of exercising, do the test again; if your pulse rate hasn't gone down, you might not be responding to the exercise you chose and you should consider a different type of workout.
Researchers found that people who didn't respond well to endurance training did respond to interval training, and vice versa. These findings suggest "there is no one-size-fits-all approach to exercise," the lead researcher tells the Times. "But it does seem as if there is some size that fits everyone." While they have yet to find any correlation between age, sex, or ethnicity and being a non-responder, researchers find it tends to run in families, suggesting genes play a role. And roughly a third of people tested fit the bill. Some non-responders benefit from higher-intensity workouts in particular, meaning that this study highlights why the "just get to the gym" advice doesn't work for everyone, Shape notes: "You're better off turning up the intensity—whether it's with bodyweight Tabata workouts, functional fitness routines, or lifting free weights." (Don't like intense workouts? Music helps.)