That commonly used expression “exercise is good medicine” is right on target! Physical activity is the best non-prescription therapy there is. Few lifestyle habits offer as many health benefits as regular workouts and there are so many ways to get your heart pumping and muscles contracting. An exercise session can be long and drawn out or short and sweet and both offer health benefits. High-intensity interval training works well for those who lack time but still want to get a fitness-boosting workout.
With high-intensity interval exercise, also known as HIIT, you trade workout time for intensity. A moderate-intensity cardio workout could take up 30 to 60 minutes. Not so with HIIT! Studies show you can get an effective high-intensity workout in as little as 10 minutes, although most high-intensity interval workouts are in the 20-minute range. Despite the reduced time expenditure, high-intensity exercise can boost both aerobic and anaerobic fitness without a large time investment.
A Time Expedient Approach to Exercise
With high-intensity training, you alternate back and forth between high-intensity exercise and slow, recovery intervals. For example, a high-intensity workout could consist of 30 seconds of vigorous, sweat-producing exercise followed by 30 seconds of low-intensity movement to recover. You choose the length of your intervals and the type of exercise you do during each one.
The key with high-intensity intervals is to get the intensity right. To get the benefits, you must push yourself! During the active intervals, you exercise hard enough that you can’t speak in complete sentences. It’s a challenging way to work out but it requires less time too. You switch time for intensity.
HIIT Training and Heart Health
High-intensity interval training offers significant benefits for the health of your heart and blood vessels too. When you compare moderate-intensity exercise, exercise where you move your body at a moderate pace for a longer period, and HIIT training, they both offer heart health benefits, despite the fact that high-intensity interval training is shorter in length.
In one study, researchers asked a group of cyclists to work out at a moderate intensity most days of the week. Their workouts lasted 30 to 60 minutes. The other group did 4 to 6 intervals of high-intensity exercise with recovery intervals in between. The intervals were 30 seconds long and the recovery between active intervals lasted 1 to 3 minutes. Overall, the HIIT workout was far shorter. However, both groups experienced similar improvements in the health of their heart and blood vessels after 6 weeks of training.
The conclusion? There is value in trading time for intensity if you have limited workout time. Some people find shorter, more intense workouts are more motivating and easier to stick with. You may not have an hour to work out, but you can manage 15 or 20 minutes for the health of your heart.
How High-Intensity Training Affects Heart Health
Some cardiologists recommend high-intensity interval training even to patients who have had a heart attack. Of course, the training sessions are closely supervised to ensure they’re safe. HIIT training, and any form of vigorous exercise, reduces arterial stiffness. Why is this important?
With age, the inner walls of arteries stiffen. This stiffness makes the artery less flexible, leading to a rise in blood pressure and a higher risk of damage to the inner wall of the artery. As the wall accumulates damage, the risk of a blood clot forming in the artery goes up. Therefore, reducing the stiffness of the artery lowers the risk of high blood pressure and cardiovascular disease.
In fact, a study published in the American Journal of Cardiovascular Disease showed that high-intensity training is more beneficial for blood vessel health and for preventing hypertension than moderate-intensity exercise. That’s one reason cardiologists recommend it.
One study presented at the American College of Cardiology’s 68th Annual Scientific Session found that subjects who performed high-intensity interval training as a part of cardiac rehabilitation after a heart attack lost fat and gained muscle.
During the study, 120 patients began with a week of moderate-intensity exercise training. After the first week, 30 subjects continued moderate-intensity workouts while the other 90 did high-intensity training. At the end of the 12-week study, those who did the high-intensity training gained more muscle (1.5 pounds more) and lost more fat (4 pounds more) than the moderate-intensity group. The HIIT group also trimmed an inch off their waistline. These improvements in body composition should lower the risk of a future heart attack.
Get the Intensity Right
To meet the criteria for high-intensity exercise, boost the intensity to around an 8 on a 10-point intensity scale during the active intervals. It should be intense enough that you can’t say more than a few words because you’re breathing so hard. The type of exercise you do matters less than the intensity. For example, you could jog in place at a rapid clip, do squat jumps, jumping jacks, pedal on an exercise bike as fast as you can, or sprint across the floor during the active interval. During the recovery intervals, do a light movement like swinging your arms and legs or do a very light jog. During the recovery intervals, your muscles recover partially so you can repeat the process back and forth. HIIT training improves both anaerobic, so you perform better during short period of intense exercise, and aerobic fitness.
Because of the intensity of HIIT training, check with your physician first and make sure you’re healthy enough to do it. Also, don’t do high-intensity workouts more than twice per week. Your body needs more recovery time between intense workouts.
The Take-Home Message
High-intensity training is good medicine for your heart and blood vessels. It’s also more time expedient than the typical moderate-intensity exercise, like brisk walking, jogging, or cycling. If you’re healthy, tackle the challenge and you can enjoy these health benefits too!
References:
Science Daily. “Brief, Intense Exercise Can Benefit the Heart, Study Shows”
American Journal of Hypertension, Volume 19, Issue 10, 1 October 2006, Pages 1037-1038l
Eur J Prev Cardiol 19(2) : 151-160, 2012.
Softpedia. “Short Periods of Strenuous Exercise as Efficient as Traditional Endurance Training”
Am J Cardiovasc Dis. 2012; 2(2): 102-110.
Med Sci Sports Exerc. 2018 Jun;50(6):1177-1185. doi: 10.1249/MSS.0000000000001567.
Open Access J Sports Med. 2018; 9: 1-17.
Citation: Kravitz, L. (2014). Metabolic effects of HIIT. IDEA Fitness Journal, Vol. 11, No. 5, 16-18.
Circulation. August 6, 2019. Vol 140, Issue 6.
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