I came across a video on YouTube that I think is critical to anyone who is old, or plans to become old one day.

Internet searches for the origin of the quote, "You don't quit running because you got old. You get old when you quit running." yield  Christopher McDougall, the author of Born to Run. I know this to be incorrect. I have known this quote all my life. I first read it in an article in Runner's World circa 1974 or 1975 by the great running philosopher George Sheehan, MD. He was a physician, senior athlete, and prolific author. At that time, many in the running community were wondering why runners, and endurance athletes in general, seemed to live longer, healthier lives. This was before widespread knowledge of Jeremy Morris' seminal London Transport Workers Study and James Fries' work. Now, a huge body of research indicates that any activity improves health, and cardiovascular training, coupled with strength training, is even more effective. Amazingly, the general public remains ignorant because of the flood of misinformation and disinformation promulgated by Big Food and various social media influencers. 

 I recently watched a video on aging and exercise on YouTube, "The #1 Antidote to Aging." Of course, this venue is full of content producers pontificating all sorts of unsubstantiated rubbish on all topics. Besides the fact that I agreed wholeheartedly with the message, what caught my attention was the caliber of the speakers. I always check sources for reliability in any contentious or academic topic. The speakers, in order of appearance, are:  



  1. Eric Kandel, MD, specialized in psychiatry and was a neuroscientist and a biochemistry and biophysics professor at the College of Physicians and Surgeons at Columbia University. He shared the 2000 Nobel Prize in Physiology or Medicine with two other researchers.

  2. Morgan Levine, PhD. is a Principal Investigator at the Altos Labs San Diego Institute of Science. Before going to Altos Labs, she was a tenure-track Assistant Professor in the Department of Pathology at Yale University and ran the Laboratory for Aging in Living Systems. She is currently working on methods to quantify system dysregulation that occurs over an organism's lifetime. 

  3. Jillian Michaels is a prominent American fitness expert, certified nutritionist, businesswoman, media personality, and author.
  4. Wendy Suzuki, PhD, is a Professor of Neuroscience and Psychology at the New York University Center for Neural Science and popular science communicator. 
  5. Daniel Lieberman, PhD., is a  Professor and the Chair of the Department of Human Evolutionary Biology at Harvard University. He is an active  researcher and has published three books relating to human evolution, health, and exercise.


After initial teasers and the message from the sponsor, Dr. Levine begins the video by making a distinction between health span and lifespan. This echoes James Fries' notion of "compression of morbidity."

"Lifespan is just the time you've been alive between birth and death. And what scientists think healthspan is is the time you're alive in a more healthy, functioning state. We want to increase the quality of life and maintain it over time and if that produces a longer life, that's an extra bonus but that's not the ultimate goal."

"Aging is associated with functional changes, things like how fast you can run or walk or your ability to go upstairs. Aging is personified by dysfunction and we see a lot of this in the diseases that tend to arise with aging."

Dr. Kandel adds that cognitive decline is also characteristic of aging. He points out that Alzheimer's typically begins in people's seventies but becomes practically epidemic by their nineties. Age-related memory loss begins in midlife.

Dr. Levine continues by noting that aging is accompanied by body composition changes such as gaining fat and losing muscle mass.

Finally, Dr. Lieberman completes the dismal picture by noting that sarcopenia means "flesh loss."

"As people get older, they tend to lose a lot of strength and power and that makes basic tasks difficult. And when that happens, people become less active, they become less fit; and this sets in motion a really disastrous vicious circle. And so, as we get older, strength training becomes really important so we can avoid those losses of vigor that are really important to maintaining your health and staying strong."

As people enter adulthood, they become less active. This lowered activity level makes them less fit. This results in strength loss. It is not unusual to see individuals in sedentary populations in their sixties and seventies who have become unable to climb stairs or even walk down a hallway. I see this at work daily.

viscious circle


Once the challenge is described, Dr. Levine offers a glimmer of hope.

"Life style is the best ticket in terms of slowing our aging process. And this is because living systems are adaptive. We adapt to our environment; we adapt to the things we experience."

Dr. Lieberman adds:

"And so health span is really the key thing. What physical activities does is that it increases your health span and your health span, therefore, increases your life span." 

"It is important to make a distinction between exercise and physical activity. PA is just moving….Exercise is discretionary voluntary PA for the sake of health and fitness. It's planned. 

Dr. Suzuki, a neuroscientist, takes a different tact by describing the effects of physical activity on the brain.

"Every time you move your body, including running, you are giving your body what I like to call a wonderful bubble bath of neurochemicals. Those neurochemicals include dopamine, serotonin, noradrenaline, and endorphins. But it also includes what are called growth factors. Several different growth factors get released during movement. And that is going towards the long-term effects of exercise that can actually help grow and strengthen two key parts of the brain. One is the hippocampus, which is critical for long-term memory. And the second is the prefrontal cortex, critical for your ability to shift and focus attention…..The hippocampus is an extraordinary structure because it is one of the only human brain areas that can grow new brain cells in adulthood. And what does that mean? Your memory is better. The other brain area that benefits in terms of growth and strength is the pre-frontal cortex. ….. Some evidence suggests that the outputs of cells from the prefrontal cortex, called the axons of those cells, perform better, work better with more exercise."

Here, I believe, Dr. Lieberman touches upon why people for more than a century have noticed that athletes just seem to age more slowly. Research has progressed from establishing whether activity and exercise make you age more slowly to how this slowdown is accomplished.

"But there's another benefit. And that other benefit is that physical activity is important because when you're physically active, you stress your body. You produce reactive oxygen species, which cause cellular damage throughout your body. It causes mutations; it causes inflammation. But because that's normal, our bodies turn on all kinds of maintenance and repair mechanisms that counter them. As we get older that repair and maintenance activity becomes really important because it prevents senescence. It prevents our bodies from decaying. So when people become physically inactive as they get older, they're no longer turning on those mechanisms that we evolved to use…..that help us to age better. And makes us more vulnerable to disease and we age faster."

This is the fundamental balance in life. Human bodies conserve any energy they can. Muscles, tendons, cartilage, ligaments, and bones are all living tissues that consume energy. When you are inactive, less of them are needed, so the body metabolizes them away. You get weaker. In order to cause your body to increase these tissues, you have to put your body under stress. 

Ms. Michaels articulates this.

"We often think of stress as evil. but in reality stress is designed to make us stronger. Somebody has osteoporosis or osteopenia…their bone density has become compromised 'with old age.' Ok. Why do we recommend working out, in particular, with weights? The idea is that stress is an injury. We injure the muscles; we injure the bones. The bone remodels and becomes more dense."

I realize that Ms. Michaels is an exercise expert but I disagree with her on one detail. Stress is not designed. Stress is a result of being alive. Living creatures are designed, or to put it more accurately, living creatures have evolved to become stronger in the presence of stress. 

Dr. Kandel adds:

"Bone is an endocrine gland. They release a hormone called osteocalcin. It enhances memory storage in young and old people. One of the reasons exercise is important is that it increases bone mass. When you exercise, you increase your bone mass, you increase your osteocalcin, and you improve age-related memory loss."

Dr. Lieberman, professor of evolutionary biology and marathoner, notes:

"As we get older, let's not cut physical activity. Let's maintain it. Do some strength. Do some endurance. The evidence is incontrovertible. The more we age, the more physical activity is really beneficial.

According to the CDC only 20% of Americans get the very minimal amount of exercise that every health organization in the world thinks is the minimum for an adult.

No one ever exercised in the Stone Age. They were physically active when they had to be."

At this point, the video comes to the inescapable fact that exercise is an essentially unnatural act. No human in a state of nature would exercise. This explains, in large part, why so few people manage to do it consistently. 

Ms. Michaels:

"For these behaviors in the moment that are less than pleasurable to become manageable, you've got to have perspective and a long-term goal that's worth it. And we call that 'Finding your why.'

You need to think about what ways health will improve the quality of your life because I'm gonna tell you right now that getting healthy is usually dis-pleasurable."

Dr. Suzuki:

"Physical activity is the most transformative thing that you can do, not only for your body but for your brain as well. That is the key message."

Dr. Lieberman, as a runner, is compelled to add:

"In fact, lots of research shows that physical activities like running actually cause your joints to repair themselves and to stay healthy. But you have to know how to do it properly."

With this remark, he attempts to correct a particularly pernicious myth that endures despite the evidence against it. Knee cartilage is living tissue. It needs to be stressed to be healthy.

The group of speakers comes to a consensus. While not everyone will be able to commit to an exercise regimen, physical activity is fundamental to healthy aging and doing any amount is better than doing none at all.

Dr. Morgan Levine finishes the video with:

"What we really want to do [in aging research] is to keep people healthy and functioning for as long as possible and if that results in a longer life, that ends up just being the added bonus."

A quote from Elaine Lalanne comes to mind: "I don’t want to be old when I’m old." I think this is the message of the whole video.