High intensity interval training workouts have become popular in recent years, particularly because they push individuals to reach a maximum heart rate and show benefits in calorie-burning and weight loss.

However, the question today is this: How long is too long?

Rachel Vaziralli, exercise expert and creative manager of Equinox group fitness, she says, “[People] think high-intensity, high volume—instead of high-intensity, low volume.” She goes on to say, “You can’t perform at a true high intensity if [the workout] is long.”

This brings about important questions: Is there a time ‘limit’ or proper duration for an ideal HIIT workout? And are there any damaging effects if one disregards time/volume/intensity all together?

HIIT was designed to be a challenge. Someone exercising is supposed to push to his or her (healthy, of course!) limits, with the intention to reach a high heart rate. That being said, HIIT is meant to be exactly as it’s acronym states: interval, meaning there is a time of maximum work, followed by rest. The high intensity isn’t consistent throughout the whole workout, or too long.

Though it makes logical sense to think that the longer you sit at a high intensity, the better, but research shows that it might actually not have as many benefits as we think.

Vaziralli speaks to this, saying, “What happens is your body just adjusts, so you hold back on the intensity. You’re spending more time than [necessary] for the same results.”

This is interesting to consider. It’s easy to get excited about a workout, and wanting to push yourself for as long as possible, but in terms of protecting muscles (especially in regards to injuries!) it may be better to have shorter, more intense workouts than long, extensive ones that can cause unnecessary wear and tear.

That all being said, HIIT workouts are great. Just make sure to pay attention to your body and keep in mind that 30-minute daily workouts may be the best and most safest for you and your body.