How High-Intensity Interval Training Slows Aging at the Cellular Level

Cathe Friedrich leads a High-intensity interval training class at Four Seasons Fitness

Who doesn’t want to slow the aging process and stay healthy and functional longer? Aging begins at a basic level – at the level of the cell and its contents, including the nucleus that houses DNA, or the genetic material, and mitochondria, the organelles that produce energy. Aging often manifests with familiar signs such as gray hairs, achy joints, and wrinkles but these are outward manifestations at what’s happening at the cellular level.

Cells accumulate damage over the lifetime of a person or animal – damage to proteins and other cellular structures like the cell membrane as well as to DNA, the genetic inside your cells. As this damage accumulates over time, it can negatively impact the function of proteins and manifest at the tissue level as organs like your heart, brain, liver, lungs, etc. begin to malfunction. That’s also when the incidence of age-related diseases goes up.

As mentioned, inside cells lie tiny organelles called mitochondria that produce the energy cells rely on to function. Mitochondria, too, become damaged over time. One theory is that mitochondria become injured due to oxidative stress and exposure to free radicals and this reduces their ability to function effectively. Yet, it’s probably more complicated than this. There’s still a lot we don’t understand about aging!

One thing that we do know is that lifestyle habits play a role in how our bodies age. Healthy lifestyle routines like eating a clean diet and exercising help reduce the damage and slow the aging process. Aerobic exercise even helps nerve cells in the brain form new connections and reduces shrinkage in a portion of the brain called the hippocampus, leading to a more youthful brain. A healthy diet and lifestyle can also reduce the burden of inflammation in your body, another factor that likely contributes to aging and chronic health problems, like autoimmune disease, heart disease, and cancer.

What type of exercise is best? We tend to think of moderate-intensity aerobic exercise, like running or cycling, as being the most beneficial for health but research suggests that high-intensity interval training may be the real fountain of youth.

Does Interval Training Slow Cellular Aging?

Researchers at the National Institutes of Health recently conducted a study comparing the effects of different types of exercise on one aspect of aging, the energy-producing mitochondria. In the study, they asked healthy, young volunteers (between the ages of 18 and 30) and older volunteers (between the ages of 65 and 80) to take part in a 3-month exercise program. Some of the participants, including both young and old, did high-intensity interval training three days per week and on two other days did moderate-intensity walking on a treadmill. Other volunteers did whole body strength training two days per week. The third group did a combination of moderate-intensity aerobic exercise and weight training, although they did fewer repetitions than the second group.

At the end of the three-month study, the researchers measured a variety of parameters, including muscle mass, BMI, strength, along with blood tests, as well as insulin sensitivity. They also took muscle biopsies of the participants’ thigh muscles. As you might expect, the second group who strength trained showed the greatest improvement in strength and muscle size. However, all three groups enjoyed upgrades in overall fitness as well as improvements in insulin sensitivity. Yet, the high-intensity interval training group had the greatest documented improvement in insulin sensitivity.

Yet, the biggest difference between the groups was at the cellular level. The participants who did interval training enjoyed the most pronounced upgrades in mitochondrial function. In fact, the younger participants experienced a 49% enhancement in mitochondrial capacity while the older participants enjoyed an even greater return, around 69% improvement. They also found that high-intensity interval training boosted the production of the proteins mitochondria use to make energy.

Why are these changes so important? Studies link a variety of age-related health problems to a decline in mitochondrial function. When mitochondria become damaged they “poop out” and can’t produce energy as efficiently, physical health begins to suffer. This can manifest as inflammatory health problems, like cardiovascular disease. Metabolic syndrome, type 2 diabetes, or arthritis.

Another Way High-Intensity Interval Training Slows Aging

Women, in particular, lose bone mass with age and the loss speeds up after menopause. High-impact, high-intensity exercise stimulates the cells, called osteoblasts, that lay down new bone and helps counteract the activity of cells called osteoclasts that break it down. You get this benefit if you do an exercise where both feet leave the floor like running and jumping. So, doing high-intensity interval training on a cycle won’t have this benefit.

Adding some plyometric intervals, where you rebound or jump, are particularly beneficial for stimulating the laydown of new bone. Fortunately, heavy resistance training pulls on the muscles, which pulls on tendons, which in turns tugs on the bones, enough to stimulate the laydown of new bone. The key is to lift heavy – 80% of your one-rep max or greater.

Also, high-intensity interval training seems to be more effective for blasting deep-seated visceral abdominal fat, the type that most strongly contributes to health problems, like type 2 diabetes, metabolic syndrome, and cardiovascular disease. Deep tummy fat produces inflammatory chemicals called cytokines that fuel inflammation and worsen insulin resistance.

The Bottom Line

Any exercise is better than no exercise but high-intensity interval training may be especially beneficial for slowing aging at the cellular level. Of course, you still need strength training since it’s most constructive for preserving muscle strength, mass, and power capabilities as you age. The combination of the two forms of exercise may be the perfect combination for slowing aging and for staying highly functional as you age. So, take advantage of the ideal anti-aging prescription and add more movement of all types to your life, including high-intensity interval training.



J Clin Invest. 2013 Mar 1; 123(3): 951–957.Published online 2013 Mar 1. doi:  10.1172/JCI64125.

Biochimica et Biophysica Acta (BBA) – Bioenergetics. Volume 1847, Issue 11, November 2015, Pages 1347-1353.

Science Daily. “How exercise — interval training in particular — helps your mitochondria stave off old age” March 7, 2017.


Related Articles By Cathe:

High-Intensity Interval Training: How Intense Does It Have to Be?

The Anti-Aging Benefits of Hiit Training

Can High-Intensity Interval Training Revitalize Aging Cells?


Related Cathe Friedrich Workout DVDs:

HiiT, Metabolic, and Interval Workout DVDs

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