High-Intensity Interval Training (HIIT): Exercise Bursts with Surprising Benefits

**By Drew Baldwin, MD, FACC**


Monitored high-intensity workouts were key in Glen Cook’s recovery.

Whether or not you’re a runner, it’s hard not to be impressed by Glen Cook’s accomplishment. The Midwest native has run the Chicago Marathon every 10 years since 1982, and he has finished faster each time.

Yet despite having been a lifelong runner, the 61-year-old Bainbridge Island resident suffered a heart attack at home in September 2016. After a three-day hospital stay, he was discharged and referred to the Virginia Mason Heart Institute’s Cardiac Rehabilitation program for outpatient care.

Once he recovered from the shock of his first major health event, Cook’s love of running and dogged determination spurred him to tell the cardiac rehabilitation staff about his dream – to run his fastest Chicago Marathon yet in 2022. For five months, he traveled to Seattle twice a week for cardiac rehab sessions. Those 36 customized sessions involved short, high-intensity aerobic workouts that were carefully monitored to ensure his safety.

The American College of Sports Medicine recommends that healthy adults should be getting at least 150 minutes of moderate physical activity throughout the week. Recent research has shown that even 10-15 minutes of vigorous exercise per day may have substantial heart-health benefits.

My usual recommendation is to get at least 10 minutes of vigorous aerobic exercise daily. In addition to that, light weightlifting, gentle stretching, and balance exercises can help to develop strength, flexibility and balance.

Few Americans achieve the amount of exercise recommended by the American College of Sports Medicine. Many report that a major barrier to regular physical activity is insufficient time. One approach to exercise that requires less time is high-intensity interval training (HIIT).

HIIT and what it involves

HIIT involves short periods of high-intensity exercise training. This is much different than the traditional long periods of steady, moderate exercise. HIIT can provide similar exercise benefits in much less time.

According to David Cowan, the exercise physiologist who supervises Virginia Mason’s Cardiac Rehabilitation program, a typical HIIT routine includes alternating bursts of intense, heart-pumping activity followed by short periods of recovery. “The recovery can either be complete rest or low-intensity effort,” said Cowan. “As long as you stick with this pattern, the chosen exercise can be whatever gets you moving – whether that’s cycling at the gym, sprinting outside, climbing stairs, or even using your own body weight for burpees and jump squats.”

A typical HIIT workout consists of performing a challenging exercise – at 80 percent to 90 percent of maximum aerobic capacity – for 30 seconds to one minute, followed by an easier exercise. That sequence is repeated, with different exercises, for 20 minutes.

Beginners can start with an easy-to-remember 10 x 1 routine: one minute of high-intensity exercise followed by one minute of recovery that is repeated 10 times.

Benefits of HIIT

The benefits of HIIT include weight loss, increased exercise capacity and overall fitness improvement. But one of the best benefits is the short amount of time required. Considering that many people cite lack of time as the main reason for not exercising on a regular basis, HIIT provides an excellent alternative to the long, boring workouts most people dislike.

Researchers around the world have conducted various studies and found HIIT to have positive effects on patients with heart conditions. In some studies, it has been shown to be more effective than continuous moderate activity at improving cardiovascular and respiratory fitness.

Forms of HITT

Interval training can be tailored for different starting levels of fitness. For instance, older adults can start HIIT with intervals of brisk walking alternated with slow walking.

A 2007 study of middle-aged and older people found that participants who trained in interval walking for at least four days per week had a reduction in blood pressure, increase in thigh muscle strength and improved peak aerobic capacity after the five-month study period. The changes seen after interval walking exceeded those seen in subjects who performed moderate-intensity continuous walking. This suggests that HIIT may do a better job at protecting against an age-related decline in fitness.

Final thoughts

Whether you want to reduce your risk for heart disease, or just improve your overall health, interval training may be an excellent option. A person who is new to HIIT should ease into it, starting with a five-minute workout three times a week then increasing the intensity and duration. If you have a health condition, always consult with your primary care provider before starting any new exercise regimen.

Drew Baldwin, MD, FACC, is board certified in Interventional Cardiology and Cardiovascular Diseases. He practices at Virginia Mason Hospital and Seattle Medical Center and Virginia Mason Federal Way Medical Center. Dr. Baldwin’s clinical expertise includes clinical cardiology, interventional cardiology, echocardiography and nuclear cardiology. He has special interest in coronary artery disease and peripheral vascular disease. Dr. Baldwin is a Mercer Island resident.


  1. Katie L. says:

    Orange Theory Fitness is a great place for interval training. If you like group fitness and a way to get your competitive spirit on. Give it a try.


    This is not spam, I truly love this workout and always promote it to all my friends and family. My boyfriend’s parents even go to it and they are in their 60s. It’s for all age groups and you will come away loving it.

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