Can Cycling Lower Blood Sugar: A doctor’s thoughts on preventing and reducing type-2 diabetes


Most people know that cycling is good for your overall fitness and health, but given that diabetes is now so common in many parts of the world, it is natural to wonder if cycling can help with it. As a doctor and cyclist, I thought I would be well placed to answer the question, can cycling lower your blood sugar?

Cycling causes your blood sugar levels to fall as you ride, this is due to the glucose (sugar) in your blood being taken up by your muscles for energy. This continues for up to 24 hours following a cycle. Cycling will also cause a reduction in your long-term blood glucose levels due to its overall health effects.

So, cycling causes a reduction in your blood sugar levels both immediately after a cycle and in the long term, but why is this? And why would anyone care about their blood sugar levels in the first place? Take a look at the rest of the article to find out.

Can cycling lower blood sugar?

How does cycling impact blood sugar in the short term?

As you cycle

Cycling has been shown in multiple different studies and real-life examples to lower your blood sugar in the short term after a cycle.

As you cycle, your body increases the uptake of glucose (sugar) from the bloodstream into your muscles. This does not only include the muscles in your legs that are pushing the pedals but also organs all around your body including the heart, which is having to pump harder as you ride your bike.

It does this by signaling to your body (using specialist signaling molecules all around your body), that your muscles are working hard, and need more energy. This causes your muscles to make specialist receptors on their surface which allows them to take up more glucose at a faster rate.

This signaling process also increases how sensitive your body is to a hormone called insulin. Insulin is another way that the body helps to push more sugar from the blood into your muscle cells and will help to lower your blood sugar.

While your particular changes in blood sugar levels will be dependent on multiple factors, we can look at previous studies to get an idea of how much cycling or exercise might impact the average person’s blood sugar levels.

Studies monitoring blood sugar levels before and after a period of cycling a bike (around 30 minutes) have a significant impact on your blood sugar levels immediately following your cycle. With the average cyclist’s blood sugar levels dropping by 25 mg/dl (which was around 20% of pre-exercise levels)

In the 24 hours following a bike ride

Not only can immediate effects be seen in blood sugar levels, but these effects also continue for up to 24 hours following exercise. Some studies show a drop of 19% in your blood sugar in the day following a cycle and others have shown that your 24-hour blood glucose levels can fall by as much as 0.5 mmol/L (a significant amount if you consider that a normal person has a blood glucose level of 4-5.9 before eating).

This prolonged drop in blood glucose levels is caused by a few factors, Firstly the raised insulin levels which reduce blood glucose levels will continue for some time, causing more prolonged effects of low blood sugar.

However, on top of this, in the period following your exercise, your body starts to replenish the stores of energy inside your muscles (called glycogen), which is made from glucose (sugar), and so your blood sugars levels drop as your body uses them up to replace your muscle stores.

This often takes place around 6 hours after your cycle, which is why it is so important to monitor your blood sugar levels even after finishing your exercise if you are at risk of low blood sugar levels (for example if you have type 1 diabetes).

How does cycling impact blood sugar in the long term?

So, we’ve established that in the period following exercise, your blood sugar levels will fall, but does this mean you need to be exercising every day to keep your blood sugar levels low?

The good answer is that regular cycling will offer many long-term benefits that will help to lower your overall blood sugar levels, even after you’ve stopped exercising.

Extras muscle mass

Firstly, as you cycle, you are likely to develop some extra muscle in and around your thighs, calves, and buttocks. We’ve already established that muscles use blood sugar to store energy for when you exercise, and this new muscle is no different.

The more muscle you have, the lower your blood sugar levels are likely to be, as more energy can be stored in the extra muscle. In fact, up to 80% of the sugar in your diet goes to your muscles for this purpose!

To take a look in more detail at the muscles you use while cycling, take a look at my article here.

Weight loss

Any form of exercise, but particularly cycling is a great way to burn calories, and losing even a small amount of body fat can have a huge impact on your blood sugar levels.

Fat (specifically tummy fat) plays a large role in insulin resistance which causes type 2 diabetes. It is a complicated process but the cells that make up fat are unable to store energy like muscle does, and produce extra body signalling molecules and hormones that make it harder for the rest of your body to use insulin.

Why is the effect of cycling on blood sugar important?

High blood sugar levels play a key role in a common health condition called diabetes. There are multiple different types of diabetes but they all require you to strictly monitor your blood sugar levels to keep the disease controlled.

Type 1 Diabetes:

Type 1 diabetes typically develops in children or young adults, it is caused by your body’s inability to make its own insulin.

Blood sugar levels are very important in type 1 diabetes as you are at risk of having too low or too high blood sugar levels (both of which can be life-threatening).

People with type 1-diabetes need to inject their own insulin, and the amount they take needs to be based on what food they’ve eaten, the activity they are doing, and their current blood sugar levels. As such, knowing what impact cycling will have on your blood sugar levels is very important.

If you have type-1-diabetes and are looking to get into cycling, take a look at the Novo Nordisk cycling team who are the first professional all-diabetic racing team.

If you are looking to start cycling with type 1 diabetes, it is important that you first consult your doctor or specialist nurse. If you do not properly manage your blood sugar levels then you are at risk of suffering from erratic blood sugar levels. In general though, you should ensure you are monitoring your blood sugar levels before, during, and after a bike ride, and managing your intake appropriately.

Diabetes.org suggests that if you are new to cycling, that this testing should be every 30 minutes until you are more confident in how your body will respond. It is also very important to keep an emergency snack available in case your blood sugar goes too low.

Again remember, that once the ride has finished, your blood sugar levels will likely be lower than normal and so you will still need to keep testing your blood sugar levels more frequently than you normally would.

Type 2 Diabetes

Type 2 diabetes typically occurs in adults, specifically overweight adults, as it is caused by your body building up a resistance to the insulin your body is making.

When it comes to type-2 diabetes, the main thing you should be monitoring is if your blood sugar levels are too high (although in reality some of the medications we use to treat type 2 diabetes can also cause your blood sugar levels to go too low like in type 1 diabetes).

It is important to note that while cycling to lower your blood sugar levels may be your goal, you do not want your blood sugar levels to drop too low during the cycle itself. It is the period after you have finished cycling where you will see the long-term benefits of your exercise, not in the hour you spend doing it.

If you try and limit your energy intake while cycling, you are at risk of not having enough energy to properly cycle, which can mean that you actually cycle less than you would otherwise! Also, as we’ve established, some people are on medications that can predispose them to low blood sugar levels (which can be dangerous), and so by not eating properly, you can put yourself at a higher risk of this.

As with type-1 diabetes or any other health condition, you should speak to your doctor or a healthcare professional before starting a new exercise regime. While I am a doctor, the advice I’m giving here is very generic and may not be appropriate for your specific situation, only your regular doctor will have a record of your previous medical history and which medication you are on that will allow them to give you official advice.

This means that if you are cycling to reduce your blood sugar, then eating on your ride can be a bit of a challenge. You want something that has enough carbohydrates or energy to keep you from having a low reading or running out of energy (called bonking in the cycling world), but not so much that your blood sugar levels spike.

This will take a bit of trial and error and you should take regular readings of your blood sugar until you have this worked out.

Below, you will see some suggestions from riders who suffer from type 2 diabetes about which snacks they take with them.

Good foods for cycling with type 2 diabetes
Bagels
Hydration drink with carbohydrates
Granola Bars
Peanut Butter Sandwich
Almonds
Peanut butter
Boiled Eggs

Does cycling prevent or reduce diabetes?

So, we’ve already established that cycling can help to reduce your blood sugar levels if you have type 2 diabetes, but does this mean it can help to reduce or even cure your diabetes?

In type 2 diabetes, the long-term complications come as a result of long periods of high blood sugar levels, and so by reducing these with exercise, you can help to improve your outcomes, reduce any complications, and in some cases even reverse your diabetes.

Studies looking specifically into the effect of regular exercise on type 2 diabetes have shown that physical activity in combination with proper nutrition can decrease cases of diabetes by up to 40%.

Not only this, but cycling will also reduce your risk of being diagnosed with diabetes in the first place, with the more time you spend cycling resulting in a lower risk of the disease itself. Some studies show that after a period of five years of cycling, you have a 20 percent lower risk of developing type 2 diabetes than those that do not.

Unfortuntaley type 1 diabetes is caused by a problem in one of your organs (called the pancreas) which means it is unable to produce its own insulin. As a result, type 1 diabetes cannot be cured, but this does not mean that the long-term health benefits of regular cycling will not still be there.

Overall

As you can see, cycling can have a huge impact on your blood sugar levels, be that in the few hours immediately following a cycle, or be that in the long term following the bodily changes that come as the result of regular cycling.

Either way, if you are looking to reduce your blood sugar levels, cycling makes a great choice.

However, as I’ve now said multiple times, before taking any new steps to manage your diabetes, you should talk to your own healthcare professional. Everyone with diabetes is different, and your approach will be better and safer if it is made with your specific needs in mind.

Mark Holmes

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

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