If you weigh the same and your muscles are shrinking, then you are adding fat
Since the lockdown began, I have had to stop doing my more intense strength exercises at the gym - I used to go three times weekly. Like you, I've read that our muscles "turn to fat" when we stop exercising.
That's a scary thought, especially after 20 years of progressively building my muscular strength and endurance.
There's good news and bad news. The good news is that our muscles don't turn to fat - that's not even remotely true. The bad news is that our bodies will accumulate more fat if we continue to eat the same amount as we did with more muscle.
You don't lose muscle, you lose the volume of muscle
What actually happens when we stop training and our muscles get smaller, is not really losing muscle. But the muscle fibres are getting smaller - shrinking. We still have the same number of fibres, which is how we can rebuild later.
This is a very clever process of adaptation by our body. Muscles take energy to feed them - hence why muscles are good for burning calories. When we stop using specific muscles our body interprets this as a signal that those muscles are no longer needed for our survival. It shrinks them in order to not waste energy, Makes sense, right?
The shrinking fibres also lose (1) mitochondria, which are the energy powerhouses of our muscles, and (2) they lose blood capillaries which have grow in response to our training in order to feed oxygen to hungry, active muscles. As these bad boys atrophy, we lose our conditioning and strength.
Here's an interesting factoid: as we build muscle size and strength new nuclei develop in our muscle fibres. Researchers found (2013) that when we "detrain", or rest for extended periods, these new nuclei remain even though the fibre size shrinks. These extra nuclei are thought to help in accelerating the recovery of our strength when we get active again.
How long before my muscles start shrinking?
How long this shrinking takes to kick in depends. It could be two weeks, or more gradually over the course of a few months. For endurance runners, it is usually a slower process - their muscles take longer to atrophy than those of weightlifters and power athletes.
In general, after about 4 weeks, there will be shrinkage of the muscle size. A 2005 study in the Journal of Applied Physiology found that for highly trained athletes muscle loss started 2 weeks after stopping training - in this case, their fast-twitch (Type 2) muscles shrank quickly.
Research has also shown that the elapsed time before shrinkage begins is inversely related to your degree of fitness. For example, if you were only moderately active, it will take a longer period, say 3 months, before you notice muscle wastage.
It's important to keep up your muscle mass if you're over 50
Although I don't push big weights at gym, I do concentrate on strength training as one key component of my focus on lowering my body age, and living longer better. Skeletal muscle mass and strength is associated with living longer, and with fewer medical complications.
I use kettlebells, bodyweight exercises, the cable machine, and free-standing classic barbell exercises to build and maintain my muscle mass and strength.
Unfortunately, I don't have a "home gym", and after the lockdown when I searched online to buy some kettlebells, the prices were just stupid. So I have not been able to keep up the strength work for about 7 weeks now.
The sequence of loss of muscle mass - you can feel this yourself
This is bad news for my muscle mass - meaning that as a proportion of my overall body weight, my lean muscle mass will be declining. That's all that happens when you don't exercise - the muscles first lose their condition, and then their strength, and then their weight. They don't turn to "fat".
This flow is a reversal of what happens when you build muscle. When you add muscle:
When you stop exercising your muscles first lose their conditioning
You might find that if you could easily do 30 push-ups 6 weeks ago, that you are now starting to struggle to do 20. Try it, if you've been in lockdown for a few weeks.
At this point, you have lost conditioning but still have your muscle strength and mass. But soon your strength is going to start to decline, followed by a decline in muscle mass.
Let's use the example of chin-ups. Most people can always manage a few push-ups, so the process of what happens when you stop exercising is not so transparent using push-ups as the example.
It's very clear when using chin-ups as an example. It happens in the reverse of those three steps above.
Let's say that when you were regularly exercising that you could do 5 clean, strict pull-ups. That is, you could hang strictly, and pull up to touch your chin positively on the bar - no swinging, kicking of legs - no momentum.
In a lockdown, this is how your muscles would weaken and atrophy:
The key concept to understand when considering what happens after stopping exercise is "body composition"
If your weight has stayed the same after 6 weeks of lockdown and not exercising as intensely or as frequently as before, then you now have more fat.
This is a simple mathematical equivalence - your muscle mass has decreased, your weight is the same, you have more fat.
If you keep consuming the same number of calories as you did when exercising, you will put on more weight, more fat. In fact, the percentage of fat in your body will start to accelerate:
How do you compensate, and retain your muscles?
If you have been doing intense strength training and have no home equipment, then it is difficult to prevent loss of muscle mass. However, if you have built up a solid basis of muscle mass, strength and conditioning, then you can retain quite a deal of it.
Add regular bodyweight exercises into your program at home - push-ups, of course, Bulgarian split squats (the King of single-leg squats), isometric pulls, strict squat jumps, planks and twisting lunges. These will all slow your loss of muscle mass.
I have provided a list of posts which cover these, and more, at the end of this post.
Nothing is going to replace 100 swings of a 20kg kettlebell, or a 200% of body weight deadlift, but you'll get back into these faster if you keep exercising.
Eat less, to avoid accumulating fat - here's how much
It's most likely that your #StayAtHome exercises burn fewer calories than then you were going to the gym regularly. Here's how to calculate what you needed before, and what you need now - based on your activity level.
This is my rule-of-thumb, which is plenty accurate enough for our purposes. Multiply your weight in kg by:
For example, for a 65g woman, the difference between very active (65 * 37) and lightly active (65*29) is 520 calories. For the 85kg male, the difference is 680 calories. Those differences are the number of calories that you have to reduce from your daily intake.
You need to eat that much less if you want to avoid adding fat or exercise more to make up for it. Even if your #StayAtHome exercise does build your muscle, it will help you avoid adding fat.
20 to 30 minutes a day to will keep your muscles healthy and ready
And there is also another magical reason why doing any exercise helps your "vacationing" muscles. Exercise is a total body response. Working on any part will benefit the entire body in the long run. Did you know that athletes who injure one side - say the left leg - help rehabilitate their injured leg by continuing to do right leg exercises!
The good news is that if you keep moving then when you get back to the gym, you'll rebuild muscle much faster than it took to gain it in the first place.
However, there is a caveat. Because muscles play a crucial role in stabilising our joints, if you have been inactive during #StayAtHome then take care not to start exercises which place a strain on your key joints. Take it slowly and gradually.
For example, walking briskly for 10 minutes burns around 80 calories. Therefore, thirty minutes equals about 240 calories. Running for half that time burns the same number of calories.
That's why, during #StayAtHome, I run 5km every day. That takes 25 minutes and burns 400 calories. Each second day I add in an exercise circuit.
Here's what I suggest:
1. Calculate your difference in daily calorie requirement before lockdown, and now
2. Add in exercise to take up as much of those extra calories as you can manage
3. Reduce some portion sizes to account for any extra calories that remain (preferably of the lower value food you are eating).
Good luck. Keep moving and you'll recover your muscles in no time once we're allowed to get back to the gym.
No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or another qualified clinician. Disclaimer.
Since I was diagnosed at 50 with Type 2 diabetes I've been learning how to do bone-building fitness training which lowers my age. You can too. It's your choice. Walter