🦠 The Powerhouse of the Cell

Good morning. Hope you’re having a great day so far. Full post today, so let’s just get into it!

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This is one of those posts I’ve been putting off for awhile. Not because I was dreading it. On the contrary, I’ve been a little too excited to write about mitochondria. This topic could be an entire graduate course. There is so much to our “powerhouses of the cell” that I wanted to do it justice when I wrote about it.

I’m sure I won’t. But in following the advice to not let perfect be the enemy of good, I’m setting out to write a “good” newsletter on mitochondria, knowing that there may well be one or many follow-up dives deeper into this fascinating and ever-important topic.

Mighty-chondria

In the most basic overview I can give you, essentially most (maybe all? There’s probably an exception) cells have mitochondria. A “mitochondrion” is the singular noun. These organelles (basically cell organs) work primarily to ~create~ energy through metabolism of nutrients. There’s a LOT of biochemistry and molecular biology (the full name of my original major, which I promptly dropped after one semester) behind those words, but that’s the essence of it. 

To not bury the lede, we want lots of them, and we want them working well—particularly in our muscles. And whaddaya know, exercise is probably the best stimulant of abundant and healthy mitochondria. chants “MOVE TO IMPROVE from the rooftops*

There are many potential sources I could cite on this topic. But there may be no better modern source than Dr. Peter Attia’s new book, Outlive: The Science & Art of Longevity. This tome is essentially a modern day Bible of holistic health and longevity, and he did a phenomenal job with it. Let’s lead with a quote here introducing the effects of exercise on our mitochondria (emphasis mine):

“Over time—or with disuse—our mitochondria become vulnerable to oxidative stress and genomic damage, leading to dysfunction and failure. Restricting the amount of nutrients that are available, via dietary restriction or exercise, triggers the production of newer, more efficient mitochondria to replace old and damaged ones. These fresh mitochondria help the cell produce more ATP, the cellular energy currency, with the fuel it does have. AMPK also prompts the body to provide more fuel for these new mitochondria, by producing glucose in the liver and releasing energy stored in fat cells.”

Attia expands in a later chapter:

“These cellular ‘engines’ can burn both glucose and fat, and thus they are fundamental to our metabolic health. Healthy mitochondria are also important to maintaining the health of our brain, and to controlling potential bad actors like oxidative stress and inflammation. I am convinced that it is impossible to be healthy without also having healthy mitochondria, which is why I place a great deal of emphasis on long, steady endurance training in zone 2.” 

Why Zone 2 cardio?

I’ve written a bit about this hard-to-define level of exercise in the past. Everyone’s definition seems to vary, but it’s essentially in a sweet spot somewhere between light and moderate intensity. You should be able to carry a conversation, but not too easily. Your heart rate may be between 60% to 70% of your max HR (though some say 70–85%). You’ll know you’ve hit this sweet spot when you do 40 minutes of it and still feel pretty fresh when you stop, and certainly that you could have kept going for awhile. If you’re “feeling the burn” of lactate accumulation in your muscles, you’re probably going too hard.

Zone 2 cardio (in any form—jogging, rucking, incline treadmill, cycling, swimming, etc.)  is right at the “Goldilocks” intensity to maximally stimulate mitochondrial health. The healthier your mitochondria get, the better you are at using fat for fuel as opposed to stored carbohydrates. 

From everyday exercisers to literal elite athletes, Zone 2 is essential. It’s widely acknowledged that elite endurance athletes spend about 80% of their weekly training time doing Zone 2 cardio—which for them is at a much higher absolute intensity than it might be for you or me, but nonetheless falls within their “light-to-moderate” Zone 2. It’s that important.

Now, cardiovascular exercise has numerous benefits for so many aspects of our health. This is really only one of them. But it may be one of the most important, and it ultimately affects our health both in the present and for decades to come.

One more quoted paragraph from Attia on why mitochondrial health—and thus this type of intentional exercise—is absolutely essential if we want to age well:

“Mitochondrial health becomes especially important as we grow older, because one of the most significant hallmarks of aging is a decline in the number and quality of our mitochondria. But the decline is not necessarily a one-way street. Mitochondria are incredibly plastic, and when we do aerobic exercise, it stimulates the creation of many new and more efficient mitochondria through a process called mitochondrial biogenesis, while eliminating ones that have become dysfunctional via a recycling process called mitophagy. A person who exercises frequently in zone 2 is improving their mitochondria with every run, swim, or bike ride. But if you don’t use them, you lose them. 

Understood. How much should we do?

Research has demonstrated that for people who aren’t doing much of any cardiovascular exercise right now, you can see tremendous benefits from two 30-minute sessions per week. That’s it! That’s so doable!

One you get used to this and can add more, it looks like doing Zone 2 cardio ~4 times a week for ~45 minutes per session is what’s ideal to give you the best mitochondrial-boosting benefits. That’s ~3 hours a week of it. No easy lift, but also not not doable for most people. Whether you use a gym, jog around the block, or can put on a 20 pound backpack and get to walking, absolutely life-changing health is not far from your grasp. 

• To complement this article, I would also like to reference a recent episode of the Look Good Move Well podcast. Marcus Filly gets pretty deep on mitochondrial health and the importance of exercise in promoting and improving it. Highly recommend giving it a listen.

• And coming in hot with one final recommendation even GQ wrote an article on Zone 2 training, so you know it’s fashionable right now. But this was also a really good explainer on its benefits and how to tackle it.

Zone 2 cardio isn’t the only way to improve your mitochondrial health, but it looks like it is probably the most effective, direct way. Other “good stressors” that produce “eustress” (i.e. a level of stress which stimulates change and growth within us but isn’t so much that it knocks us down a level) can boost mitochondrial health as well. Think resistance training, saunas, plant-rich diets, dietary restriction, maybe red light (?), etc. 

Our mitochondria deserve the reputation they have built. Without them, we wouldn’t be able to use energy, which means we really couldn’t move. But with them, we can metabolize anything we eat with pristine efficiency, enabling us to move long distances for long periods of time. Robust mitochondrial health will almost certainly extend our lifespans and healthspans. 

Be a powerhouse. Be like mitochondria. And thank your high school biology teacher for the unforgettable analogy. 

✅ Take Action

Every newsletter's Take Action section will invite you to take small steps to improve your health. Recognizing that we all have different capabilities, I'll offer three different levels of action you can choose to take.

Level 1: Pick a cardio exercise of your choice. It can probably even be speed walking if you’ve been sedentary. Commit to two 30-minute sessions a week for three months. You will reap enormous benefits even if you are unable to directly see them!

Level 2: Want to do it all but tight on time? Incorporate Zone 2 into your weight training workouts. As I wrote last week, I’m switching things up in the weight room and taking significantly longer rest between sets. So on my upper body days, I can hop on a bike or treadmill and do some chill Zone 2 work while I’m resting before my next set. Give that a try!

Level 3: Optimize. Alongside at least twice per week resistance training, complete 3–5 Zone 2 training sessions a week that last 45 minutes to an hour. You’ll be on the podium in Paris 2024 before you know it!

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✍️ Drew's Picks:

• Listen: How big tobacco intentionally made snacks addictive.

•  Listen again: G Flux: How to burn fuel faster. This is that podcast from Look Good Move Well. Give it a listen!

Hope you have a wonderful week. I’ll be back in your inbox next week! As always, feel free to reply with any feedback, questions, or suggestions 💌 

Keep moving,

Drew

The content in Move to Improve is meant to be informative in nature, but it should not be taken as medical advice. It is always a good idea to consult with a trusted health professional before making any major lifestyle changes that could have a significant impact on your health. This is not a medical resource, and any opinions and articles are not intended for use as diagnosis, prevention, and/or treatment of health problems. They are not substitutes for consulting a qualified medical professional. Please think critically and take what I say with a grain of salt (aka don’t sue me).