Mitochondria are about to be your new favourite organelle, if they aren’t already. They’ve been my favourite since I was 7. Let me explain why.
Mitochondria are the powerhouses of the cells. Think of them like nuclear energy power plants that supply your cells with energy. They break down the carbohydrates, amino acids and fatty acids from the foods we eat and turn them into ATP, which is the cellular form of energy. Without ATP, we die. So our mitochondria are essential to our survival.
What’s super awesome about mitochondria is that they have their own DNA and you inherit them from your mother. It’s believed that they were originally a separate type of bacterial cell that formed a symbiotic relationship with the bacterial cell that had engulfed it and that new type of cell went on to start a revolution of biology, allowing complex multicellular organisms to occur.
We owe a lot to mitochondria. So how can we best support our mitochondria and get the most from them?
What’s neat about mitochondria is that they will up-regulate based on increased energy demands - meaning, endurance training makes them replicate. This is why exercise increases your basal metabolic rate. The more mitochondria you have, the more food they break down for us, the more energy they produce for us, the more calories you need to maintain them. Disuse of muscle, sedentary behaviour and ageing all decrease the number of mitochondria we have, and therefore lower or metabolic rate. Luckily, you can very easily reverse any loss of mitochondria by exercising more, which is awesome since more mitochondria has been linked with a decreased risk for heart disease, type II diabetes, and healthier cells which can slow down the effects of ageing.
A lot of different kinds of exercise have been studied for their effects on our mitochondria - aerobic exercise, strength and endurance training, etc. The good news is just about any kind of exercise produces biogenesis. However, if you’re trying to get the most ‘bang for your buck’, high intensity interval training - alternating between periods of high intensity exercise and periods of lower intensity exercise, like running as fast as you can for 1 minute and then jogging for 2, repeated for 15 minutes - has been shown to increase muscle mitochondrial ATP production and improve muscle endurance despite a significantly reduced total exercise volume than traditional aerobic exercise. In fact, a single bout of low-volume, high-intensity interval training can activate mitochondrial biogenesis and double endurance capacity as compared with aerobic exercise of the same energy expenditure. Which means that you can have a bigger impact from shorter workouts just by including high-intensity interval training. Research shows you can achieve more progress in 15 minutes of interval training (done three times a week) than you can by jogging on the treadmill for an hour. And according to a 2011 study presented at the American College of Sports Medicine Annual Meeting, just 2 weeks of high-intensity intervals improves your aerobic capacity as much as 6 to 8 weeks of endurance training.
So how do you do it? I’ll let you read this from the American College of Sports Medicine for a great overview.
I’m not going to get into mechanotransduction in this post, you can read about that here. But what I do want to say about strength gains is to make sure you’re allowing adequate time for recovery in between workouts to maximize strength. Think about a muscle like strands of uncooked spaghetti that are each wrapped in saran wrap. Then take bundles of ten of those strands and wrap that bundle in saran wrap. Then take a bunch of those bundles, wrap the whole thing in saran wrap and stick it in water and you have a basic muscle. The individual spaghetti strands are what we call muscle filaments. A bundle of filaments is called a muscle fibre. A bunch of fibres make up a muscle. The goal when exercising is to break some of the filaments. This is the signal to your body that the muscle wasn’t strong enough to lift the load and is also what causes delayed onset muscle soreness. Your body will replace those filaments and then add a few more for good measure so that the next time it comes up against a similar weight, it will be better prepared. You do not want to tear a muscle fibre, because fibres replace with scar tissue, and a muscle with a scar is only at best 80% as effective as muscle without one, so if you’re trying for strength gains, you’re shooting yourself in the foot without allowing that repair process adequate time to occur. Plus, scar tissue is sticky and takes longer to heal. Filaments take about 48 hours to replace. A torn fibre takes two weeks.
I’m going to say this again because when it comes to athletes, you guys sometimes really need the reminder - this is why it’s so important to give yourself adequate rest time between work outs - if your muscle wasn’t strong enough to lift the load originally, now you’re working with fewer filaments. If it wasn’t strong enough before, it definitely isn’t now, which means you are that much more likely to tear a fibre if you work out again too soon. And that takes two weeks to heal. This is what sets people up for tendonitis. That scar tissue, during those two weeks is sticky and fragile and likely to re-tear if you go back to your normal routine, which we’ve already established you were’t strong enough to handle the first time around. So you re-tear those fragile fibres, and that requires more scar tissue, which you will re-tear the next time you work out… see where I’m going with this?
Work out hard, sure, but rest for at least 48 hours in between, longer if it was a really hard work out. And make sure to give your body the proper nutrition it needs to be able to replace and repair those damaged filaments. You can see this post here about that.