When was the last time you felt like an Olympian during your workout?
That’s a hard “nope” for us, too.
But if you’re doing high-intensity interval training (HIIT) — you’re practically Simone Biles. After all, the exercise routine was created in the 1950s to help elite athletes improve their performance.
Admittedly, the workout for Olympians was a bit more intense than the HIIT routines most people do today — but it’s still giving Biles vibes.
And it turns out HIIT may be able to do more than just improve performance. Some health benefits associated with HIIT include decreased risk for cardiovascular disease (the number one killer of women in the U.S.), lower blood pressure levels and mental health perks.
But is “high intensity” too intense?
Here’s what science says and everything you need to know about high-intensity interval training.
What is HIIT?
High-intensity interval training is pretty much just like it sounds. The exercise routine involves cycles of brief, high-intensity exercise periods alternating with low-intensity recovery periods. Because of the intensity, the workouts are short — usually 30 minutes or less.
HIIT can be integrated into pretty much any exercise routine such as running, walking, biking or dancing. It’s important to pick something you like so you can stay motivated.
The goal is to significantly raise your heart rate during the high intensity part to at least 80% of your maximum heart rate. (To find 80% of your maximum heart rate, subtract your age from 220 and multiply that by 0.80. For example, if you’re 50 years old, your max heart rate is 170, and 80% is 136.)
During the low-intensity activity, your heart rate drops, but it’s still elevated compared to your resting heart rate. The sustained increase burns calories and improves cardiovascular fitness — two main draws of the workout.
How does HIIT work?
HIIT sessions usually start with a 5-10-minute warm up, followed by a cycle of 30 to 90 seconds of high-intensity exercise, depending on what you can tolerate. Then, you do low-intensity exercise for 30 to 90 seconds or longer. Repeat this cycle multiple times over the workout.
Here’s an example of a beginner HIIT routine:
- Warm up by walking for five minutes
- Walk or run as fast you can for one minute
- Go back to your warm-up pace or even slower for three minutes
- Repeat the cycle five times
Why do people like HIIT?
HIIT has become increasingly popular over the years. You’ve probably seen variations of the workout on social media or online — there are HIIT videos on YouTube that have millions of views.
The workout has stayed in the spotlight for a few reasons:
- It’s easy. You can take any cardio exercise — walking, jogging, riding a bike — and make it HIIT by alternating the intensity. You can also apply HIIT to strength exercises such as push-ups, squats, lunges, etc. or combine both cardio and strength training. The world is your HIIT oyster!
- It’s quick. Most HIIT sessions last between 10 and 30 minutes.
- It’s effective. One minute of vigorous activity is about the same as two minutes of moderate-intensity exercise. And getting close to your max heart rate causes post-exercise oxygen consumption, which basically means you’re going to continue to burn calories even after your workout is over.
What does science say about HIIT?
After consulting everyone’s good friend, Science, there is research to back up the potential health benefits of HIIT and the benefits of HIIT vs. other types of exercise.
Here are some of the noteworthy findings:
- HIIT burns fat. One systematic review of 15 studies found that HIIT workouts led to a significant reduction in body fat percentage among women. Another review of 29 studies found HIIT was superior in reducing waist circumference, fat mass and improving peak oxygen uptake compared to moderate-intensity continuous training (MICT).
- HIIT can lower the risk for cardiovascular disease. One analysis of 22 studies found that people who do HIIT can achieve greater reduction in cardiovascular disease risk factors when compared to MICT.
- HIIT can lower blood pressure. A systematic review published in the Journal of Science and Medicine in Sport found that people who did HIIT had lower blood pressure during the day and at night compared to people who did MICT.
- HIIT can lower blood glucose. One analysis of 20 studies found that participants with Type 2 diabetes who did HIIT had significantly better blood sugar levels compared to participants who didn’t do HIIT.
- HIIT can improve overall fitness and quality of life. A 2026 study of women 65 and older women found that the participants who did three sessions of HIIT a week showed improvements in functional fitness — the ability to do everyday activities like carrying groceries — and quality of life compared to the women who didn’t do the workout.
- HIIT can boost mental health. One analysis found that HIIT led to improvements in mental well-being, depression and perceived stress compared to people who were not doing the workout.
The risks of HIIT
There are some risks to think about when it comes to high-intensity interval training.
HIIT releases the hormone cortisol in the body, but if it’s done too often, it can cause a range of problems, including mood changes, anxiety and sleep issues. But if you get enough sleep and eat properly, then your cortisol levels should drop back down to normal ranges within a few hours of doing HIIT.
Some HIIT workouts may include high-impact movements that can lead to injuries if you’re not doing the exercises properly, or you’re prone to injuries or have joint problems.
You can also HIIT too hard. Because of the intensity of the activity, HIIT should only be done a max of three times per week. Too many HIIT workouts can cause burnout and injury among other problems.
If you can, hiring a personal trainer can help you learn progressions and proper form, which can help you avoid injuries.
Who shouldn’t try HIIT?
Although HIIT is generally safe for most people, it’s not for everyone.
It’s a good idea to talk to your clinician before trying HIIT, especially if you have high blood pressure, high cholesterol, diabetes or heart disease.
HIIT the (exercise) jackpot
For many people, high-intensity interval training is like the Swiss Army Knife of exercise.
It’s versatile — no special equipment required — easy to do and you don’t have to dedicate a lot of time to get a good workout in. That means more free time to shine your gold medals. Win, win!
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