1527 Reasons to Exercise

I’ve been reading more reviews of fitness-related studies over the past few weeks, and two studies, in particular, recently caught my attention.

In the first study, researchers recruited previously sedentary females to perform aerobic exercise six days per week for three weeks. Three days each week included steady-state cardio on a treadmill while the other three days included interval sessions on a stationary bike.

While body composition changes were underwhelming—there was basically zero body fat loss or muscle growth—aerobic power and mitochondrial capacity in the legs increased significantly. (Mitochondria are the parts of cells which produce energy.)

Now none of that is particularly surprising: on the body composition front because there were no nutritional modifications, and on the aerobic power and energy production fronts because there was a large increase in training time.

That said, there was one interesting finding: Just three weeks of this varying intensity cardiovascular exercise produced changes in 1,527 genes. In particular, some of the genes that were downregulated are involved in inflammation while some of the genes that were upregulated are involved in fat turnover (both the storage of triglycerides in body fat tissue and their removal/breakdown/use for energy).

I’ll come back to why that’s important in a minute. Before we get there…

In the second study, researchers analyzed data from genome-wide association studies about age-related declines of certain traits including appendicular lean mass (muscle mass in the legs and arms), grip strength, walking speed, and cognitive function.

They found that a causal relationship exists from lean mass to all of the other three abilities, as does a reverse causal relationship from cognitive functioning to lean mass and walking speed.

Basically, that means a decrease in muscle mass predicts declines in not only grip strength and walking speed (which you’d probably expect) but also in cognitive functioning (which you might not expect). Conversely, a decrease in cognitive functioning (e.g. memory, decision-making) predicts declines in muscle mass and walking speed.

Of course, this doesn’t mean that you’ll develop Einstein’s intellect if you strength train to build lean mass or Schwarzenegger’s physique if you take up chess to improve your mental abilities. What it does mean is that doing what you can to maintain/build lean mass and support your brain is vitally important if you want to maintain both (or even either) as you age.

And that brings me back to the importance of the first study’s observations and some takeaways from both studies:

1. Some inflammation is necessary for normal body functioning. But excess inflammation has been linked to a host of issues from heart disease to diabetes to dementia (and other neurodegenerative diseases) to difficulty building muscle mass. So anything we can do to reduce it is beneficial. This includes exercising as well as eating fewer processed foods, getting enough sleep, and managing stress.
2. Even in the absence of a negative fat turnover balance (i.e. fat loss), fat turnover itself is beneficial because highly mobilized fat has more mitochondria. Body fat that has more mitochondria is more readily used for energy, while body fat that loses mitochondria becomes more inflammatory and less sensitive to insulin. This means exercise that increases fat turnover is beneficial for the brain and muscle mass, even if it’s not used in conjunction with nutrition changes to alter overall body composition.
3. Aerobic exercise decreases inflammation and increases fat turnover, but it isn’t particularly useful for building muscle. For that, you have to lift stuff that’s at least moderately challenging for you.
4. Aerobic training, strength training, cognitive functioning, and general health are interconnected. We don’t have to do everything perfectly in each area, but any improvement that we can make in any area should provide some type of benefit to some of the others.

Often the visible benefits of improved body composition or performance are what we’re after when we begin to exercise. And it’s completely understandable to feel at least a little frustrated if we don’t see the specific benefits that we want after putting in what might feel like a lot of time and effort. But an important point to remember is that exercise of any kind does improve our health on some level. (Or 1,527 levels.)

Putting it into practice

This week consider how you can get in just a little more movement than usual.

Go for an extra walk after dinner. Or take a yoga (or kettlebell) class. Or dance, hike, ride your bike, swim, play pickleball, clean up the basement, or lift something heavy at the gym.

Of course, working toward some visible goal is generally motivating. So doing an extra set or three of pull-ups, swings, squats, or anything else you’re working toward is probably the best option.

But whatever the case, remember that any exercise^† you do will contribute to a healthier future you.