Very short version
More physical exercise gives you more energy and a longer life.
Short version
Physical exercise is a signal for the body to repair (thus live longer) and to improve mitochondria (thus have more energy).
The results:
You live longer and better
Life is easier because you have more energy
You do more in life. So you live even longer
Life is more pleasant because you have more energy
Long version
In childhood I was active because my parents put me into various sports, including four years of water-polo.
Then in high-school I gave this up to focus on studies.
In University I had transformed from a high-energy kid to a perpetually tired old man. Some of it was awful eating and sleeping. But most of it was because I had a sedentary lifestyle.
The more I lay on the couch doing nothing, the less energy I had to do anything.
All activities were more tiring. But I could avoid the more strenuous ones to ignore the decrease in energy.
A wake-up call came from a hike. It was an easy trail that I knew from childhood.
Yet it was devastatingly difficult for me in University. This was a signal I was in trouble. One I could not ignore.
I took up sports again and slowly gained energy.
Now I do intensive exercise (Crossfit) and endurance work (trail running in summer, backcountry skiing in winter).
I have more energy at 35 y.o. than I ever had at 20 y.o.
This is more than perception. Science is uncovering how we can influence our cellular age. Exercise is the most potent such signal. It is a way to make yourself younger. Conversely lack of exercise makes you older.
Exercise is the Pool of Youth
One way physical exercise improves health is it signals the body to activate its repair mechanisms.
This happens through hormesis.
Hormesis is the adaptation that occurs in response to low to medium stress.
It occurs when you suffer stressors, but then have time to recover. Physical exercise creates hormesis. As does hunger, fatigue, social pressure, fear, any other stressor. Even poison in small quantities creates adaptation: resistance to that poison.
When we experience stressors which we survive and then recover from, our body adapts in response. This is why running makes you a better runner, why fasting makes you more able to go without food, and so on.
Hormesis is key to stopping or even reversing ageing. More on this in later posts. Now the focus is on exercise, which is a type of hormesis.
Physical movement is a powerful stressor. It breaks muscle fibers, creates damaging free radicals, inflicts inflammation at the muscle level, strains the cardiovascular system, the bone system, the nervous system.
If your body was like a car, small stress would add up to catastrophic failure.
But our body is not like a car.
In response to stress, we don’t degrade, we adapt.
The stress of physical exercise triggers the body to repair the damage and enhance the systems that were used. Your muscles get bigger. Your cardiovascular system becomes more efficient. Your bones grow stronger. Your peripheral nervous system gets faster.
But it’s not just that you get better at the exercise that you do. Your body improves overall.
Physical exercise gives energy
Doing sports and then having more energy than if you were sedentary is counter-intuitive.
Our unconscious model of the world assumes that if you expend energy, then you have less of it. It pushes towards conservation of energy (being lazy) because that was advantageous for most of human history. Our ancestors had to run for food and survival, it was beneficial to rest whenever they could.
But the science of biology shows our intuition is wrong.
Doing the effort of hard physical exercise makes everything else easier in the long term.
A universal adaptation to physical exercise is improved efficiency and number of mitochondria. These are organelles which produce energy for your cells. They are the engines of everything that you do, feel and think.
More and better mitochondria means more energy.
More energy means a better life. You do more things with less effort. You think better. You make better decisions. You are generous instead of selfish. Long-term instead of short-term. Considerate instead of rash. Enthusiastic instead of lethargic.
More energy means more life. You spend less time resting and recovering. You have more activities in your life.
Research shows that as humans we perceive time mainly by counting the relevant activities and events that take place. Doing nothing or the same things over and over feels like less time than having many rich experiences. More energy means you live a subjectively longer life.
Physical exercise increases lifespan
Lead longevity scientist David Sinclair states in his book Lifespan that science has not yet identified all the ways in which exercise improves health and lifespan, but that it is certainly critical.
Physical exercise signals repair processes in the body.
These repair processes improve health and longevity.
The benefits of exercise on living longer are indisputable. They even feature in WHO guidelines.
Exercise is so important that scientists have problems measuring its effects. There was a recent big study on exercise called the Generation 100 study. It aimed to measure the effects of regular exercise during a 5 year period. However it failed to do so because its test group did HIIT training (high-intensity interval training), while the control group were not sedentary, but rather did MICT (medium intensity continuous training). Both groups exercises five days per week.
Why did the researchers not choose a control group that was relevant, aka did not do exercise? Because they felt it was unethical to get people to not do exercise. This is how certain science is that exercise is critical to health.
Evolved to move
Our ancestors did varied physical exercise often. They did not do it to burn calories or build six-pack abs. They did it to survive and thrive.
For them a workout was hunting for a mammoth or escaping a predator. It was climbing trees for fruit, digging for tubers and moving to a different location.
They did endurance exercise. As nomads they moved constantly. One surviving ‘primitive’ people, the Tarahumara regularly run 50 to 80 miles per day.
They did strength work. They moved and carried heavy objects. They did not have cars, tools, machines. Everything was done with their own strength.
They did flexibility and skill work. Climbing precarious trees. Crouching and twisting in various ways. Resting in a crouch position, not on chairs like us.
They did high intensity exercise. Predators and prey were not planned but occurred. When an opportunity, or a threat, arose, our ancestors had to act in the moment. A five minute all out sprint with obstacles could happen at any time.
What to do
“Get off your butt.’ David Sinclair, longevity researcher
First step is to do low intensity exercise every day. Walking is the simplest and best because it uses most of your muscles and cardiovascular. The stereotypical goal of 10,000 steps might be too much. You can get benefits from as little as 4,000 steps per day. But this does mean getting off your butt, and finding moments to do these walks.
It’s best to incorporate them in your life. Walk part of your commute. Take a walk after lunch. Take a walk as a work break.
Second step is to incorporate more exercise in your life. There are three types that you should take into account: high intensity, aerobic and strength. They can overlap.
Aerobic is medium intensity exercise for relatively long periods. A marathon pace or slower one-hour run qualifies here.
High intensity is exercise with high heart rate, but for shorter periods. Interval training qualifies here. As does Crossfit.
Strength training is exercise where you push your muscles to their maximum power. Weightlifting and powerlifting qualify here. But it can also be done with bodyweight.
Ideal is to mix these three types throughout each week: aerobic, strength and high-intensity.
How you achieve this depends on your context and preferences. For aerobic for example you could do morning runs or you could go for bi-weekly volleyball sessions with friends.
What I do is Crossfit three times per week coupled with one-two long endurance activities, such as trail running and in winter backcountry ski-touring. Crossfit covers the high intensity and strength bits, trail running/ ski-touring cover the aerobic. Often the latter is a one weekend day and it also provides immersion in nature.
Don’t worry about being perfect in your exercise regimen. We don’t yet know the perfect protocol.
Worry about moving as much as possible. In return you will have a longer and better life.
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Previous Ideal Life entries:
References and further reading on Physical Exercise:
Lifespan - David Sinclair
Lifespan podcast - David Sinclair