Dr. William Evans—Why Muscle Mass is a Marker of Longevity

Should the elderly engage in physical activity? How do nutrient needs change throughout the lifespan? Researchers and scientists worldwide strive to get revolutionary answers to top aging questions. Our guest is one of them. 

In this episode of the Longevity by Design podcast, our co-hosts, Dr. Gil Blander and Ashley Reaver, are joined by Dr. William Evans, adjunct professor of Human Nutrition at the University of California, Berkeley. In this episode, Dr. William Evans discusses his research on exercise in older adults, how protein requirements change during the lifespan, and how this contributes to aging as a whole. Tune in to the latest episode to find out more. If you're interested in learning more about longevity in sport, you definitely will not want to miss this one.

Meet Longevity by Design’s podcast guest, Dr. William Evans

Dr. William Evans is an Adjunct Professor of Human Nutrition at the University of California, Berkeley, and an Adjunct Professor of Medicine in the Geriatrics Program at Duke University. Dr. Evans' research examines the functional and metabolic consequences of older people's physical activity and how dietary protein and energy needs change with advancing age. He was the first to describe sarcopenia, the age-related loss of muscle mass and strength. Additionally, Dr. William Evans’ research sheds light on the connection between sarcopenia and lower levels of biomarkers like testosterone, estrogen, growth hormone production, and increased insulin resistance.



Dr. William Evans’s research on physical activity in older adults 

What do we know about exercise in the elderly? 

Before Dr. William Evans began his research, there was a notion that exercise might be more harmful than beneficial at a certain age. “We attempted to dispel that notion. We could essentially apply many of the concepts that we knew about exercise and training to older adults. It had never really been done before. My laboratory was the first to show that older people were remarkably responsive to increased levels of physical activity.”

Does age impact adaptation to exercise?

Dr. William Evans showed that if older adults properly approach fitness, they can expect results that are not that different from younger adults. "We wanted to address the question, 'Does aging in some way prevent the adaptation that we make to regular aerobic exercise?' We matched the amount, intensity, frequency, and duration of exercise in healthy older and younger people. We found that the absolute gains in maximum aerobic capacity were the same between healthy older and healthy younger people. Essentially they had regained the fitness that they had lost in the previous 30 or 40 years in three months of exercise."

Dr. William Evans described the term sarcopenia

"I was the first to describe the condition sarcopenia. The term was coined by Irv Rosenberg, the Director of the Nutrition Center. We observed that muscles in older people were smaller than muscles in younger people, so the word sarcopenia, which in the way that I described it, is the, “age-related loss of muscle mass”. 

Cohort studies found that the amount of lean body mass, or even changes in lean body mass, seemed unrelated to changes in function, risk of disability, and even mortality. Changes in strength appeared to be far more associated with these outcomes. Over the last 30 or so years, the term sarcopenia has taken on a slightly different meaning. 

Until recently, we've had no way of measuring how much muscle someone has in their body. Muscle mass, instead of lean mass or fat-free mass, is a particular part of the body that doesn't lend itself terribly well to measurement. Dr. Mark Hellerstein, at the University of California, Berkeley, invented a brand new way to measure how much muscle mass you have in your body.



Muscle mass becomes a prominent measure of health and aging

After being able to measure and research muscle mass, Dr. William Evans's findings show that the approach to muscle mass and overall health had been wrong for so many years. Now, Dr. William Evans believes that muscle mass is a top marker of aging. Here's why. 

"Muscle mass is strongly related to things like how fast you walk, grip strength, and fracture risk. In fact, it appears that in very old adults, muscle mass is more strongly related to the risk of a hip fracture than is their bone density. If you think about it, in very old adults, bone density is low, but muscle mass is variable. We've shown that muscle mass is strongly related to mortality among older adults, in ways that lean body mass is not at all."

The relationship between muscle mass and aging

Dr. William Evans and his team conducted an exercise trial with very elderly nursing home patients, a typically sedentary population. Patients received a weightlifting HIIT protocol, additional protein, or both. As Dr. William Evans recounts, "I think that those studies resulted in a tremendous interest. We were able to show that, for the first time, this process that we all thought was inevitable and unchangeable, which is the age-related loss of strength and muscle, is, in fact, treatable."



Nutrient needs change throughout the lifespan

Dietary needs also change as individuals age. "We have a reduction in the number of calories that we need and simultaneously have an increased need for protein. The reduction in growth hormone and testosterone, and to some extent estradiol, reduce the efficiency of protein synthesis, leading to what people call anabolic resistance." Young adults have far greater rates of muscle protein synthesis than older adults. Therefore, older adults have increased protein needs to match muscle protein synthesis rates in younger adults. 

Maintaining body weight is particularly important. Increasing dietary protein intake over time is also essential, and it isn't easy in many cases. Protein supplementation, particularly with very high-quality proteins, might be of some benefit. "Proteins that are rich in essential amino acids are far more efficient at stimulating muscle protein synthesis and helping to maintain muscle mass." 

Dr. William Evans concludes, "There are so many older people that the whole fitness industry has completely ignored and left out. My recommendation is to pay attention to prevention."

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