Over time, your exercise budget may change. As you age, your body needs more recovery time, so it may be necessary to count more hours of rest between strenuous workouts. It is also limited by other things that are happening in your life. Spending long hours at work or traveling or dealing with stressful situations at home can drain a portion of your energy budget and decrease your ability to recover from exercise, says Dieffenbach. A 2016 study of 101 college football players, for example, found the risk of injury nearly doubled during times of academic stress (such as midterms and final week).

The most reliable signs that you’re exercising too much come from your subjective feelings of well-being, says Dieffenbach. If you’re suddenly tired all the time, or if an exercise that once seemed easy seems difficult, or your performance suddenly declines (e.g. if your running time slows down without explanation, or your daily walk is longer than usual) it may be time to back off and rest, said Dieffenbach. Other classic signs of overtraining include difficulty sleeping, feeling tired, and being unable to recover from minor colds and other respiratory infections. “Sometimes you have to step back to move forward,” says Dieffenbach.

If you start to force yourself into an exercise you previously enjoyed or feel guilty about not exercising enough, that’s another sign that you’re overdoing it. This is especially true if the sensation lasts for more than a few days, says Dieffenbach. (Of course, it can also be a sign of other health problems, such as depression, so you should be aware of that too.)

On the other hand, if you find that your love of sports is turning into a crazy obsession, that too deserves attention, says Szabó Attila, a health psychologist who studies exercise addiction at Eotvos Lorand University in Budapest. Sports addiction can occur when a person feels compelled to do physical activity despite pain or injury. One of Attila’s studios of 2019 found that no specific number of hours in a week could be correlated with exercise addiction, but “it becomes problematic when it impairs other areas of life,” he says. If you’ve put exercise above your relationships, work and everything else, Attila adds, that’s a sign that it’s become too much.

One of Attila’s colleagues, Mark Griffiths, a psychologist at Nottingham Trent University in England, has developed six criteria for use during exercise addiction monitoring by a healthcare specialist:

1. Sport is the most important thing in my life.

2. Conflicts arise with my family or my partner because of the many sports that I do.

3. I use exercise as a way to change my mood (eg to run away, get high, etc.).