We all know exercise is good for your cardiovascular health. But some types of exercise may be better for the heart than others, and some research suggests the wrong exercises could be putting your heart at risk.

“Too much of anything is bad for you, so if you’re constantly performing HIIT every day, you’re going to stress your body and heart and not give it time to heal,” said U.K.-based personal trainer Niko Algieri.

“In addition to heart health, too much of the stress hormone, cortisol, in the body can lead to loss of muscle [and] fat retention, and increase your risk of illness and injury.”

Some experts suggest that moderate-intensity workouts are best for improving heart health. This is because moderate exercises are easier to maintain and can result in fewer complications later on. Additionally, slow-paced exercises may not provide the heart with as many benefits as previously believed.

According to the British Heart Foundation (BHF), HIIT benefits the body by improving VO2max—the maximum oxygen you can provide to your muscles to create movement during exercise—which is a marker of cardiovascular fitness.

Another benefit, says the BHF, is that HIIT creates new organelles called mitochondria, which take the fat and carbohydrates you eat and convert them to usable energy.

“For most individuals, it is safe to participate in high-intensity training, and if you have a heart condition, you should always discuss any kind of new exercise you wish to take part in with your doctor,” the BHF recommends.

But even if you have a heart condition, it should not deter you completely from exercising. Working alongside your doctor can help you find safe exercises that also improve heart health. Always remember to exercise at a pace that works best for you and does not lead to discomfort.