Updated: Apr 15, 2020
HIIT stands for high-intensity interval training, It’s an exercise routine in which you give maximum effort at high intensity bursts, followed by a quick rest phase and repeat this interval. These rest phases and high-intensity intervals add up to your desired workout length. For example, a HIIT routine could consist in running on the treadmill at an all-out sprint for 30 seconds, resting, then repeating the sprint–rest sequence several minutes. You can also do HIIT right in your living room with jumping jacks or burpees for 15-25 minutes.
What are some of the benefits of HIIT?
Some of the benefits of a HIIT workout include improved anaerobic and aerobic fitness, improves cardiovascular health, it builds lean muscle, improves endurance, increases your metabolism and in turn it burns fat during the exercise and even for hours after you’ve completed the routine, which is one of my favorite benefits to share with my patients and clients. This phenomenon is commonly referred to as “the after-burn” and known to us experts as “excess post-exercise oxygen consumption, or EPOC. Which simply means that there is an even greater oxygen uptake with higher intensity exercises and this requires energy. According to the American College of Sports Medicine, EPOC generally tends to add 6 to 15% more calories to the overall workout energy expenditure with HIIT routines.
How does it impact the body differently than steady-state?
What we know is that it has been well documented in the literature that high intensity workouts burn significantly more total calories and fat calories overall when compared to a conventional steady-state aerobic exercise routine, such as jogging.
A well-known study done by the Journal of Physiology showed that 10 one-minute sprints was equal to several hours of steady-state cycling in burning fat.
How do I get the most out of my HIIT routine?
It depends on your level of experience, but I typically will recommend my beginner clients and patients to start off with one HIIT workout per week and gradually increase the frequency and intensity as your endurance improves. As you add another HIIT workout be sure to take “rest days” in between each workout to prevent overuse injuries and allow for optimal muscle recovery.
HIIT workouts should never exceed 30 minutes regardless of your fitness level, and when done effectively even 15 minute routines can be highly effective.
The key to an effective HIIT routine is during the High intensity interval phase to exercise at 75-80% of your maximum heart rate for 2-3 minutes (difficult to hold a conversation), followed by an “active recovery phase” at 40-50% of your maximum heart rate for 2-3 minutes (can mildly hold a conversation). There are some HIIT protocols that allow for a 30 second “non-active recovery phase” this may be a better protocol for beginners.
What are some potential risks that a "newbie" should be aware of?
Possible risks with HIIT exercises that are important to point out is increased coronary artery disease in individuals that have a sedentary lifestyle. Which is why discussing Family History and Medical History (i.e. cigarette smoker, high blood pressure, diabetic, or high cholesterol) thoroughly with a physician to determine if HIIT is safe for you or what is the safest way to introduce a HIIT program based on your health status.
Another risk that I warn my patients and clients about is “Overuse Injuries” due to too long and too frequent of a HIIT workout. Remember less is more with HIIT routines. So, I encourage individuals to implement rest days between workouts regardless of their fitness level, to reduce the risk or injury and allow for optimal muscle recovery. A HIIT workout should never be over 30 minutes, and ideally I would recommend limiting it to 15-25 minutes and no more than 4 days per week.