HIIT | This Specific Form of Exercise May Slow Aging

Do you wish you could slow down the clock on aging? Research shows that a specific form of exercise – called high intensity interval training (HIIT) – will do just that. HIIT involves short bursts of intense aerobic activity, intermixed with stretches of lower intensity exercise. Although HIIT won’t take away wrinkles, a Mayo Clinic study has shown that it does slow and reverse some age-related changes at the cellular level.1

The best exercise for aging adults

According to the 12-week Mayo study, HIIT is good for individuals of all ages, but it’s especially beneficial for older adults.

The study’s goal was to find evidence to help develop targeted therapies and exercise recommendations for individuals of various ages. Mayo researchers compared the effects of HIIT, resistance training, and workouts combining a mix of resistance and cardio.

The researchers observed that HIIT seems to reverse the age related decline in mitochondrial function. Mitochondria, commonly called the powerhouses of the cell, create energy rich molecules called ATP that are used by cells to carry out bodily functions.1

As you age, the ability of mitochondria to produce energy slowly decreases. Study participants, ages 18-30, who engaged in HIIT had a 49-percent increase in mitochondrial function, while an older group of HIIT participants, ages 65-80, saw a 69 percent increase.1

HIIT also increased protein synthesis and triggered the growth of new muscle, helping counteract the inevitable muscle loss that comes with aging. In fact, some age-related deterioration of muscle cells was actually reversed.1 

Researchers verified that both high intensity and combined training improved aerobic capacity and mitochondrial function specific for skeletal muscle.1 They also verified that strength training was most effective for building muscle mass and improving strength – which is no surprise. And all training types improved lean body mass and insulin sensitivity among participants. But the HIIT group showed the best results at the cellular level. 1

The take-home message:  For aging adults, supervised high intensity training is probably best, because both metabolically and at the molecular level, it confers the most benefits. 

HIIT: No equipment needed and simpler than you think

HIIT doesn't require special training or equipment. And it benefits people at all fitness levels. The HIIT participants combined stationary biking three days per week with two days of treadmill walking. But only the biking portion incorporated a high intensity workout.

After warming up, the cyclist pedaled four minutes at 90 percent or more of their individual peak oxygen consumption, then three minutes at a minimal oxygen load. They repeated this pattern four times. 

You don’t need to know your peak oxygen level or maintain high intensity for four minutes to benefit from a high intensity cycling routine. To begin, warm up for three minutes at an easy pace. Then pick it up to as fast as you can, without feeling a burning sensation in your muscles, and hold it for about 30 seconds. Take it back to the easy warm-up pace for three minutes, and repeat for four rounds. 

The purpose of HIIT is to raise your heart rate for a short period of time, then lower it again. Catch your breath during the lower-intensity portion of the workout – but keep moving. This is literally building the strength of your heart muscle. You only need to repeat this cycle four or five times to reap the benefits.

It doesn’t matter if you bike, run, skip rope, or combine movements – the concept is the same. In one study, walkers who added high-intensity intervals to their walking routine improved their aerobic fitness, leg strength, and blood pressure.

They did it by alternating between three minutes of fast walking and three minutes of slow walking for 30 minutes four times a week.2 Peers who walked twice as long but at a moderate, consistent pace made minimal gains in fitness or other measures – similar to a comparison group that didn’t exercise at all.2

HIIT: Your workout, your way

A quick web search returns a plethora of HIIT workouts. The key to success is to do the right moves for you at your own pace.

If you simply want to vary your exercise routine, then you can determine the length and speed of each high intensity interval based on how you feel that day. After a warm up, you might increase the intensity for 30 seconds and then resume your normal pace. How much you pick up the pace, how often, and for how long, is up to you.3

Interval training needn’t involve high impact exercise, jumping movements, or heavy weights. Instead, start slowly. If you think you're overdoing it, then slow down. As your stamina improves, challenge yourself to vary the pace.3  You might be surprised by the results.

HIIT: Compatible with many health conditions

Although it’s always best to check with your healthcare professional before you start a new workout routine, studies have concluded that HIIT is safe and beneficial even for individuals with diabetes or heart disease.4

In a 2017 study, individuals with heart disease who alternated between fast and slow pedaling (20 and 40 seconds, respectively) on an exercise bike safely improved how fast their heart rates slowed to normal after exercise, an important marker for longevity.4

Every workout shouldn't be HIIT

Experts recommend just one or two HIIT workouts a week, combined with light or moderate aerobic exercise and strength training in between.5,6 This is important because the time between hard workouts allows your body to recover and increase strength.5-7 

December 30, 2019 • Brent Bauer, M.D.


  1. Robinson M, Dasari S, Konopk A, et al. Enhanced protein translation underlies improved metabolic and physical adaptations to different exercise training modes in young and old humans. Cell Metab 2017;25:581-592.
  2. Masuki S, Morikawa M, Nose, H. Interval walking training can increase physical fitness in middle-aged and older people. Exerc Sport Sci Rev 2017;45:154-162. 
  3. Rev up your workout with interval training. Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/interval-training/art-20044588. [Accessed Nov. 19, 2019]
  4. Villelabeitia-Jaureguizar K, Vicente-Campos D, Senen A, et al. Effects of high-intensity interval versus continuous exercise training on post-exercise heart rate recovery in coronary heart-disease patients. Int J Cardiol 2017;244:17-23. 
  5. High-intensity interval training. American College of Sports Medicine. https://www.acsm.org/docs/default-source/files-for-resource-library/high-intensity-interval-training.pdf?sfvrsn=b0f72be6_2.  [Accessed Nov. 5, 2019]
  6. Fit facts: High-intensity interval training. American Council on Exercise. https://www.acefitness.org/acefit/fitness-fact-article/3317/high-intensity-interval-training/. [Accessed Nov. 5, 2019]
  7. Myers C. Don't call it a comeback: Moderate-intensity exercise is still effective. American Council on Exercise. https://www.acefitness.org/certifiedarticle/6490/don-t-call-it-a-comeback-moderate-intensity-exercise-is-still-effective. [Accessed Nov. 6, 2019]

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