Does Cycling Burn Muscle: How to protect your gains and bulk while cycling


I’ve spent many hours of my life sitting at the gym, lifting large weights around in an attempt to get some muscles. But every time I tell anyone that I’m a cyclist, the first thing I always hear is that it will ruin my muscle gains. I thought I’d spend some time looking into the details of this so we can put this to rest once and for all. So, does cycling actually burn muscle?

Cycling can cause your body to burn muscle, but only in certain situations. These include if you are not eating enough calories each day or if you are no longer working the muscles you want to maintain. In these cases, your body will break down your muscle and use that energy for other functions.

So, your body may break down muscles as you cycle when in certain situations. But why does it do this? And how do we make sure that the muscles we have arent going to be lost to our weekend bike ride? Finally, how do you optimize further strength training while cycling?

Do you lose muscle when cycling?

Why do our bodies burn muscle?

In order to answer this question correctly, it’s useful to understand how your body gets its energy for cycling in general.

Your muscles contain something called glycogen, this is just a chemical that your muscles use to store energy. As you cycle, your muscles use up their glycogen stores to fuel the muscles as they start to work.

Once you are finished exercising, or even partway through longer cycling trips, your muscles will have used up their glycogen stores and so your body will start looking for ways to replenish them.

First of all, your body uses the energy flowing around in your bloodstream. This is the sugar or carbohydrates that you have eaten recently. These are a good source of energy however your body does not have many of these either. There is only a finite amount of glycogen your body can make from what you ate that day.

After your body has used up all these carbohydrates, it will then start to burn your body’s fat stores. These are again a great source of fuel for your body and can create a larger amount of glycogen. This is what you are trying to do when cycling to lose weight or fat. You want to try and keep yourself in this zone where you are burning fat rather than anything else.

However, in some situations, your body will go one step further and start to break down muscles to use as energy. There are a few situations this might happen, for example when your body is in a “starvation mode” and there is no fat left to burn. There are some other specific circumstances we’ll look into later.

Put simply, your body prioritizes food, then fat, then protein when deciding what to break down as you exercise.

This means that theoretically, as long as you don’t allow your body to get to this final stage, you will burn (near) zero muscle from cycling.

However, there are a few situations where this might not be the case.

In what situations will cycling burn muscle?

We’ve already established that there are a few situations where your body will choose to burn muscle rather than fat. The two main ones that apply to cycling are running at a calorie deficit or when you are not using the muscles you want to keep.

Running at a calorie deficit

We’ve already established that in a period of starvation, your body will start to break down muscle for energy. In some situations, while cycling, you may find your body gets “pushed” into this stage, specifically if you are not giving your body enough calories to fuel the activity you are doing.

This is very common during a “cut”. A period of weight training where you are trying to lose excess body fat without losing muscle. In these situations, you are often trying to run on a lower calorie intake, often at a calorie deficit. In these cases, excess aerobic exercise such as cycling will burn more calories, and thus risk putting you into the stage of muscle burning.

On the other hand, this does mean that as long as you consume enough carbohydrates to maintain a surplus you’re in (near) zero danger of muscle loss for this reason.

Lack of muscle use

This form of muscle loss comes as a result of no longer using the muscles as much as you were. This might be a result of spending more time cycling that you were previously using for weight lifting. It might also be the result of you focusing on different areas during your weight lifting training such as those legs you always forgot about.

On top of these, when you are both weight lifting and cycling, you will probably be spending less time doing each activity than if you were focusing on one alone. This isn’t only because of the time you spend exercising, but the extra rest days you may end up taking or through more injuries.

Even once you’ve spent time building muscle, your body has to use a constant supply of energy to maintain its new larger size. When you aren’t using the muscles anymore, your body decides to prioritize that energy for other areas, and so over time, those muscles will revert to a size where there is enough muscle for your (now lower) activity level.

This is where the saying “use it or lose it ” comes from.

How do cyclists keep muscle?

There are some basic steps that you can take as a cyclist to protect your muscles from being burnt as you cycle. Most of these are quite simple now you understand which situations cause your muscle to be broken down in the first place.

First of all, make sure you eat enough calories to keep you out of a calorie deficit. Use a calorie calculator such as this to work out exactly how many calories you need each day. If you are doing lots of cycling make sure to account for this in the total you need each day. If you start to fall below this you are at risk of burning muscle.

It is not only calories you need to be monitoring. In order to maintain muscle, you will want to ensure you are eating enough protein each day as well.

Cycling works your lower limbs a lot (there’s a lot of muscle mass down there), which takes protein to recover. You can work out how much protein you need by using your weight.

Aim for 1g of protein per pound of body weight per day.

The second main step you can take to ensure you do not lose muscle mass is to continue your muscle training while you cycle. Over time, any muscles that your body is no longer using will be atrophied (broken down) to prioritize energy in other areas you are actually using.

If you start cycling, you can expect to lose muscle mass if you swap out all of your weight-lifting sessions for riding. Instead, you should look to build cycling into your already established weight lifting regime, in order to maintain this muscle mass.

This is the reason that cycling is more prone to burning your upper body muscle than it is to your lower body muscle. As you move from strength training to cycling you are continuing to use many of the muscles in your thighs and calves, but your arms are only minimally used during a bike ride, and so will be the first to lose their mass.

Does cycling limit muscle gains from weight lifting?

So, we’ve established that cycling will not cause you to lose muscle mass in most situations, as long as you take a few key steps such as increasing your calorie intake and maintaining your weight lifting routine. But what if you’re looking to build more muscle? Will cycling limit any future gains?

While it is possible to cycle a long way with lots of muscles or lift a lot of weight when you’re skinny, you will have to accept that your performance in both cycling and weight lifting will suffer compared to if you were training for these two disciplines individually. At the top level of either sport, you won’t be the best at both weight lifting and cycling. Bodybuilders and endurance cyclists look different for a reason.

Studies have shown that combining cardio (such as cycling) and weight lifting can impair muscle growth by a third. That’s a big difference when you’re already having to work so hard. In fact, the more cycling you do and the harder you are cycling, the harder it is to gain more muscle.

Studies have also looked into how much cycling may be too much when weight lifting. It appears that any more than 3 days a week of cycling is likely to impact your muscle mass a lot more than amounts less than this.

As you can see from the graph below, endurance training (aka cycling) for 4 days or 5 days a week had a much more significant impact than 3 or less.

https://pubmed.ncbi.nlm.nih.gov/22002517/

But, they have also shown that the majority of this negative impact comes as a result of improperly combining cardio and weight lifting exercises. You can almost fully overcome this problem by properly timing your cycling and weight lifting (as well as ensuring you have the correct diet).

How to limit the impact of cycling while trying to build muscle?

While you can’t expect to reach the highest levels in cycling and weight lifting, you can definitely do both together. It will just require you to adjust your training schedule and diet.

First of all, you want to ensure you are taking all the steps we looked at above. Make sure you are eating the right food, with the right amount of calories and protein in your diet. Ensure you are drinking enough water and getting enough rest. These might all sound simple, but these basic principles will take you a long way.

There are also some other, more specific changes, you should add to your training regime if you are looking to optimize muscle gains while cycling.

Make sure you are leaving a suitable gap between your cardio work and any weight training. In fact, you should make sure you are leaving at least 6 hours to ensure your gym session is affected as little as possible.

On the other hand, you also want to ensure your body has enough time to rest after strength training, so ensure you avoid any high-intensity cycling in the 12 hours following a weight session.

A small caveat to this is if you plan to do a shorter cycle (less than 30 minutes). The research has shown that cycling has a lesser impact in these situations and thus will not have as much of an effect.

This might all seem a little daunting, having to spend so much time and effort planning when to do your strength training and when to go on a ride, but you need to remember, that as long as you are keeping to a calorie surplus, either cycling or weight lifting will be beneficial, they just won’t be as optimal as they could be.

Certainly, when I asked a large group of cyclists, it seemed that very few of them were aware of this need to time their different exercises with one another, and a very similar percentage of those that timed and did not time their gym sessions with their cycles were happy with the progress they had made at the gym.

Overall

While cycling can cause you to burn muscle, this does not have to be the case. By properly monitoring your diet, continuing your strength exercises, and timing your cycling appropriately, you can maintain a good muscle mass while cycling. Although, you might have to accept that you’ll never be the best at both.

Mark Holmes

30-year-old doctor with an interest in cycling, bikepacking, and statistics.

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