In this post we explore the ageing process and the benefits of exercise as we age, with a particular focus on high-intensity interval training (HIIT). Unfortunately none of us can avoid getting older, but exercise could be a way to keep our bodies healthier for longer.

We explore more below, adapted from Pete McCall’s Ageless Intensity.

How we age

“Although…every physiological system shows some decline with age, the amount of decline, the systems affected and the age at which the decline begins are highly variable and specific to each individual”

McDonald, 2019

Just as no two snowflakes are alike, no two adults will age exactly the same way. Likewise, exercise will affect each person differently. Research can provide a general idea of the results from a particular mode of exercise, but exercise is only one variable that influences how the body changes; other factors include nutrition, sleep, and overall level of stress.

Although there is no way to guarantee specific results from any exercise program, the evidence does suggest that a lack of regular physical activity is bad for your health. A sedentary lifestyle with a lack of physical activity is a risk factor for developing heart disease; in fact, the World Health Organization (WHO) estimates that globally up to 5 million deaths a year could be avoided simply by increasing levels of physical activity. In addition, the WHO suggests that individuals who do not meet the recommended levels of physical activity have a 20 to 30 percent greater risk of an early death when compared to those who perform sufficient levels of physical activity (World Health Organization). So, while there is no guarantee about the results, the evidence suggests that not exercising could take years off your life.

How exercise gives you the ability to change how you age

The good news is that exercise in general, and high-intensity exercise in particular, can allow you to retain your youthful strength, power, and aerobic capacity as the years pass on the calendar. The challenge is knowing how to do the right types of exercise in the appropriate amounts to receive the greatest benefits.

Three types of exercise can do the most to mitigate the aging process: mobility training; muscle force production, which includes exercises for both muscular strength and power; and metabolic conditioning with a specific focus on high-intensity interval training (HIIT), which could do more to slow aging than traditional steady-state exercise programs. Yes, we already know that exercise is good for us, and chances are that you already exercise on a regular basis, but up until now most of the information on exercise related to aging has focused on low- to moderate-intensity exercise. If you have already been exercising throughout adulthood, you’re used to pushing yourself. You have the ability to function at a high level of fitness and do not need to be relegated to lower-intensity exercise just because of your age.

Not only can high-intensity exercise burn more calories and help create lean muscle, but heavy strength training or explosive power training can produce different responses in the body that may support successful aging. Therefore, you want to be sure to include them in your workout program. You don’t have to stop high-intensity exercise as you get older. In fact, this is when it could probably help you the most. You want to make sure that as you age, you exercise not only harder but also smarter.

The benefits of different exercise modes

Mode of exercise	Benefits
Mobility training	Increase tissue extensibility Enhance joint ROM Improve ability to perform foundational patterns of movement: – Hip hinge– Squat – Lunge – Push– Pull – Rotation Improve dynamic balance (the ability to control a moving center of gravity over a changing base of support)
Strength and power training	Increase muscle size and definition Increase BMD Enhance resiliency of connective tissues Increase production of satellite cells responsible for building new tissues Increase production of muscle-building hormones Increase muscle force outputMaintain levels of lean muscle mass for an efficient resting metabolism Increase levels of BDNF to reduce risk of developing dementia or Alzheimer’s Increase activation of type II muscle fibers Improve efficiency of glucose metabolism Enhance confidence and levels of self-esteem Improve functional performance for ADLs
Metabolic conditioning	Enhance cardiac outputIncrease blood flow to muscle tissue Increase capillary density Increase aerobic capacity Enhance mitochondrial density Increase energy expenditure (weight loss) Lower blood lipid profiles to reduce risk of high cholesterol Reduce risk of developing different types of cardiovascular disease Increase levels of BDNF and muscle-building hormones

Can HIIT help reduce the risk of developing chronic health conditions?

One risk of aging without regular exercise is developing chronic health conditions like heart disease, obesity, and type 2 diabetes; and yes, as with other forms of exercise, the evidence suggests that HIIT could be an important component for greatly reducing this risk. When you work at higher intensities, muscles will metabolize carbohydrate, specifically muscle glycogen, to produce ATP; one important benefit of exercise during the aging process is maintaining efficiency of carbohydrate metabolism in the muscle cells. Specific enzymes like LPL are used to metabolize FFAs into ATP, and different enzymes are required for type II muscle fibers to convert glycogen to ATP.

Research at Ball State University found that adults in their 70s who maintained a high level of fitness throughout their life span had enzyme levels similar to adults many years younger (Gries et al. 2018). This means that performing high-intensity exercise consistently through the aging process could help you to metabolize carbohydrate much more efficiently and reduce your risk of developing type 2 diabetes; because lower-intensity exercise relies on aerobic metabolism, it may not deliver the same benefit.

Hypertension is a common risk factor for developing further cardiovascular disease that could result in an early death. As arterial stiffness increases, it is more challenging for the heart to perform its function of pumping blood around the body. It’s widely accepted that low- to moderate-intensity cardiorespiratory exercise can help improve aerobic capacity and reduce risk factors, like hypertension, that could lead to heart disease. It’s important to note, however, that evidence is accumulating that HIIT could be an even more effective option than lower-intensity exercise for those at risk of heart disease. In a review of the literature comparing HIIT to continuous moderate-intensity exercise, Ciolac (2012) observed that the former is “superior” to the latter for improving cardiorespiratory fitness and improving numerous health markers that lower risks of developing hypertension and other forms of cardiorespiratory disease.

HIIT has been used successfully to help individuals reduce risk factors for heart disease, and in their review of the research on HIIT, Gibala and Shulgan (2017) found that studies have suggested that patients who have experienced heart attacks or heart surgery could benefit from HIIT as a component of rehabilitation. They also found that other studies showed that shorter, more intense workouts with HIIT could provide more favorable outcomes for heart patients than moderate-intensity, steady-state exercise. In one study, interval workouts were found to put less stress on the heart than steady-state aerobic exercise. In another study that lasted seven years, researchers tracked cardiac rehab patients who participated in both moderate-intensity and HIIT workouts and concluded that the risk of a cardiac event is low for both modes of exercise in a supervised setting. Another study noted, “The results of this randomized controlled study demonstrate that high-intensity aerobic exercise is superior compared to moderate-intensity exercise for increasing cardiorespiratory fitness in stable coronary artery disease patients” (Gibala and Shulgan 2017).

Many of these benefits are similar to those derived from high-intensity strength and power training, and yes, they are important benefits, but the body cannot function at high intensity all of the time, which is why it is important to perform lower-intensity workouts as well. During lower-intensity exercise, you can help promote recovery from more challenging workouts while burning calories, but without placing as much stress on your body.

Summary

We know that exercise is good for us, but as we age many may opt for lower intensity workouts. Pete McCall’s Ageless Intensity suggests that weaving in high-intensity workouts can allow us to reap the health benefits.

Read more about exercise and ageing, and gain access to specific exercises and workouts in Ageless Intensity.

References

McDonald, R. 2019. Biology of Aging. 2nd ed. New York: CRC Press.

Ciolac, E. 2012. “High-Intensity Interval Training and Hypertension: Maximizing the Benefits of Exercise?” American Journal of Cardiovascular Disease 2 (2): 102-10.

Gibala, M., and C. Shulgan 2017. The One-Minute Workout: Science Shows a Way to Get Fit That’s Smarter, Faster, Shorter. New York: Random House.

Gries, K., U. Raue, R. Perkins, K. Lavin, B. Overstreet, L. D’Acquisto, B. Graham, et al. 2018. “Cardiovascular and Skeletal Muscle Health with Lifelong Exercise.” Journal of Applied Physiology 125:1636-45.

Header photo by Anna Shvets from Pexels

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