Many people want to get healthier or perform sports better, but not everyone has the free time to train like an Olympian.
“Lack of time” is often cited as a major barrier for not meeting the recommended physical activity guidelines of 150 minutes per week—a goal only 40% of Americans achieve. As a way to sidestep the time barrier, there has been a recent rise in the popularity of high-intensity interval training (HIIT), which was the second ranked fitness trend in 2020. HIIT involves alternating periods of intense exercise with periods of low-intensity exercise for recovery. The selling point for HIIT is its time-efficient nature. Instead of spending hours in the gym, HIIT promises the benefits of a marathon-length workout in a shorter period of time.
There now seems to be a contest for who can create the shortest workout. This was the focus of a symposium at Experimental Biology 2021 called “Time-efficient Physical Training for Cardiovascular Health.”
Jenna Gillen, PhD, from the University of Toronto in Canada, kick-started the discussion about the interest in and importance of HIIT for health and gave some examples of popular workouts, including sprint interval training (SIT) and a very short, yet intense, HIIT workout that can be completed in around 10 minutes . Even with a very low time commitment, low-volume HIIT and SIT have been shown to have similar cardiometabolic benefits compared to moderate-intensity continuous training.
Gillen also discussed HIIT in the context of at-home exercise, which became extremely relevant during the coronavirus stay-at-home orders, when everyone was confined to their homes. Even without fancy equipment, fitness fanatics can still perform HIIT and SIT activities, such as stair sprints, effectively. Both HIIT and SIT can significantly improve aerobic fitness and metabolic health.
“Exercise snacks” were also discussed as another less structured way to get moving daily. Climbing a flight of stairs, biking to work, carrying groceries or doing a set of pushups at your desk all count as exercise snacks. Rather than scheduling dedicated time for physical activity, this more incidental form of exercise is more spontaneous, but may still provide strong health benefits if you move enough throughout the day.
Additional scientists presented their work on HIIT, including studies that suggest you could improve your health with five minutes of breathing exercises or by participating in one very high-intensity cycling session per week. These activities aren’t a cake walk, but boosting fitness by breaking a sweat just once per week seems enticing.
This compelling research suggests that even if you can’t make time for a structured exercise session every day, you can still improve your cardiometabolic health using time-efficient HIIT and exercise snacks throughout the day. In the end, movement is beneficial, no matter how you get it in.
Brady Holmer is a PhD student in exercise physiology at the University of Florida. His lab focuses on cardiovascular physiology, mainly how exercise can play a role in health, disease and aging. Holmer hosts a podcast called “Science & Chill,” where he sits down with scientists in the fields of physiology, biology, health and nutrition to discuss their work. He served as a meeting blogger for the American Physiological Society’s 2021 annual meeting at Experimental Biology.