Does HIIT Work?
The American College of Sports Medicine predicts that HIIT will be the top fitness trend in 2018. There are a number of gyms that offer HIIT programs. Which leads us to ask, Does HIIT work?
The answer is elusive because many different exercise programs are called HITT. Does HIIT mean one thing? And if so, what is that one thing? Does that one thing equal the thing that you call HITT?
Researchers have questions of their own. Specifically, they have asked:
- Does HIIT work for cardiac patients?
- Does HIIT work for diabetics?
Does HIIT work for cardiac patients?
HIIT works for senior cardiac patients. It may give them more exercise-related benefits than does steady state aerobic exercise.
The title of the paper is, “Superior Cardiovascular Effect of Aerobic Interval Training Versus Moderate Continuous Training in Heart Failure Patients.” It was originally published on June 18, 2007. It has become one of the most cited articles about HIIT.
What do we know about the 27 subjects of the study?
- Aged 50 and up
- Suffered heart failure
- Took Beta-blockers and ACE inhibitors
- Normal weight
What was their HIIT?
They walked on an incline (up to 11%) for 4 minutes at an intensity equal to 90-95% of their maximum heart rate. They followed that with a 3-minute walking break. Then, that work-rest sequence was repeated, for a total of 4 rounds.
There was a cool down and warm up period before and after the actual HIIT. The total exercise time was 38 minutes, including warm up and cool down. They did the workout 3 times per week.
A comparison group simply walked continuously at an intensity equal to 70-75% of peak heart rate. Their workout lasted 47 minutes and was also done 3 times per week.
Both groups exercised for 12 weeks.
Every pulmonary measure, which were taken before and after the 12-week exercise program, improved more with the HIIT patients than it did with the steady-exercise subjects. Even more to the point, a couple of measures only improved among the HIIT subjects.
Does HIIT work for diabetics?
HIIT works for seniors with type 2 diabetes.
The title of the paper is, “Low-volume high-intensity interval training reduces hyperglycemia and increases muscle mitochondrial capacity in patients with type 2 diabetes.” It was originally published on August 25, 2011. It has become one of the most cited articles about HIIT.
What do we know about the 8 subjects in the study?
- Between 50 and 70 years old
- Had type 2 diabetes
- Took a variety of medications—metformin, gliclazide sitagliptin, etc.
- All overweight, some were obese
What was their HIIT?
They rode a stationary bike for 60 seconds, at an intensity equal to 90% of their maximum heart rate. They followed that with 60-seconds of rest or slow pedaling. Then, that work-rest sequence was repeated, for a total of 10 rounds.
The total exercise time was 25 minutes, including a warm-up and cool down. They did the workout 3-times per week, for 2 weeks, for a total of 6 workouts.
Measures of glucose control and skeletal muscle adaptations were taken before and after the HIIT program. Each one of those measures improved.
What is HIIT?
We have already seen that HIIT can be exercising for 60 seconds, but it could also last 4 minutes. The recovery interval can be 60 seconds, but it can also be 3 minutes. The exercise can include treadmill walking as well as stationary biking.
The most frequently recurring element that I see in HITT training is…intensity. The exercise is usually done at about 90% of maximum heart rate.
We offer an Athletic Circuit Training class that allows an exerciser to turn it into a HIIT workout. That’s because we assign each workout for 30 seconds, and each exercise is followed by 15 seconds of rest. Each exerciser therefore has the option to go all-out, which would turn it into a HIIT workout. Some of our participants do exactly that. It’s difficult—even by HIIT standards—but they love it!