How cycling can boost your immune system

Cycling comes with all kinds of benefits. It improves fitness and wellbeing, gives you more energy and is a cheaper – and often faster – way of getting around than driving or public transport.

But did you know it could also mean you’ll get sick less often? Regular cycling can improve the functioning of your immune system, making it more effective when it comes to fighting off infections.

What is the immune system?

First things first, let’s take a quick look at what the immune system is. It plays a vital role in your health by protecting you from the harmful invaders such as bacteria, viruses, fungi, parasites and germs that can make you ill, as well as cell changes within your own body.

These harmful substances are known collectively as pathogens. An antigen is a subpart of a pathogen that causes the immune system to produce antibodies to fight off the disease. A healthy immune system is quicker at identifying antigens and more efficient at producing antibodies – proteins that work to attack, weaken and destroy antigens.

The system is a complex network of organs, cells, tissues and proteins that together defend the body against infection and toxins, while protecting the body’s own cells. It also promotes healing when you’re unwell or injured. It includes things like the thymus gland, bone marrow, white blood cells and lymphatic system.

It is incredibly sophisticated and even today it’s not fully understood how it all works. However, even from this simplified explanation, it’s easy to see how important it is to your overall health. This is why it’s so important to make sure it’s as strong as possible, and that’s where cycling comes in.

A boost to your immunity

If you’re looking for fewer days lost to sickness – and who wouldn’t be? – then cycling could be the answer. Studies have shown that cycling to work reduces absenteeism, with cycle commuters taking fewer sick days than non-cyclists. Those who cycled more often and longer distances had the lowest numbers of sick days.

There’s little doubt that physical activity can boost your immune system. Professor Geraint Florida-James is the research lead for sport, health and exercise sciences at Napier University in Edinburgh.

He is also the academic lead at the Mountain Bike Centre of Scotland, where he coaches and trains enduro-MTB riders. He maintains that for those looking to strengthen their body’s immune system, cycling is a great activity.

He says: “As humans, we were never designed to be sedentary, and study, after study, after study has shown that being active is good for you, and that includes your immune system.”

Cardiovascular exercise – such as running, walking, cycling, dancing or aerobics – gets the heart pumping, moving blood around the body to get oxygen to your muscles to power them.

This increase in heart rate also improves the circulation of natural killer cells, T cells and B cells around the body. These are all white blood cells that play an important part in fighting off disease by identifying and eliminating infected cells.

Physical activity helps stimulate the lymphatic system as the working muscles keep lymph moving and flowing by opening and closing lymphatic valves. The lymph nodes are where the body fights off infection while lymph vessels work to drain waste fluid, regenerate tissue and detoxify the body, lightening the load on your immune system.

Why cycling is the best exercise

Cycling is excellent cardiovascular exercise. It’s low impact, and apart from the bike itself, requires no special equipment, gym membership or place to go to. The availability of non-standard and electric cycles means it’s open to most people. Although it must be acknowledged that the cost of these cycles can be a barrier.

Prof Florida-James adds: “We will all see declines in physical abilities as we age, and the immune system is no different. What we are trying to do is slow that decline as much as possible. Cycling is a great way to do this as the body is supported and it is less impactful on the musculoskeletal system.”

Cycling is also easy to incorporate into your life. You can do it where and when best suits your lifestyle. You don’t have to get to a gym or turn up at a particular time. You can cycle to work or to the shops, hit the trails or go for long leisurely weekend rides.

What’s more, it seems that 70-year-old cyclists have the immune systems of 20-year-olds. A study published in the journal Aging Cell followed 125 people between the ages of 55 and 79 who had cycled regularly throughout their adult lives. They were compared to adults of the same age who didn’t exercise regularly and adults aged 20 to 36.

The results were astounding. The body fat of the older cyclists was as low as that of the 20-year-olds. They had also preserved muscle mass and strength. What’s more, the cyclists’ T cell – the ones that help fight infections – levels were the same as those of an adult in their 20s.

The thymus gland, which is responsible for producing T cells, typically starts to shrink from the age of 20. But this study found that the cyclists’ thymus glands were the same size as the 20-year-olds’. This could explain why the thymuses of older cyclists were found to be generating as many T-cells as those of much younger people.

Further factors

Vitamin D is an essential nutrient to the healthy functioning of the immune system. It keeps the system in balance by regulating the immune cells. Getting outside on your bike is an excellent way of soaking up some rays, which promotes the synthesis of vitamin D.

Stress also plays a part. Cortisol, the hormone that’s released when you get stressed, influences the effectiveness of the immune system. In short bursts, cortisol helps to reduce inflammation, which is known to suppress the immune response. Moderate exercise like cycling is perfect for this.

However, consistently high levels of cortisol, when you’re chronically stressed, for example, actually increases inflammation which puts more pressure on your immune system. Cycling can help here, too.

Many people use cycling to reduce their stress levels. In fact, when we asked on social media recently what the benefits of cycling to work were, one of the top answers was arriving at work a lot less stressed. Cycling is one of the most popular stress-busting exercises out there, ranking above any other aerobic or gym activity.

You don’t have to go all out

The good news is that you don’t have to be Marianne Vos or Mark Cavendish to reap the benefits. Little and often should be your watchwords here. The key is consistency and building habits such as cycling to work or to the shops are ideal for this.

Just 15 minutes of moderate-intensity exercise, like cycling, at least three times a week is enough to boost levels of natural killer cells in the blood. This means that even a beginner cyclist travelling at an average 20kph/12mph on a 5km/3-mile commute is improving their immune system every time they ride to work.

And, of course, they have to get home too. So if this is you, you’re doing twice the minimum, up to five days a week, all without even thinking of yourself as a ‘cyclist’. The same goes for cycling to the shops, with the added benefit of carrying the shopping back with you and so increasing the intensity.

If you want to do more, there’s nothing stopping you, of course. It’s all about finding what works for you. But, if you’re looking for more reasons to get that old bike out of the shed, then knowing that just a short ride to work or the shops will help cut down on days spent sick is surely a good one.

Can you overdo it?

It used to be thought that intense exercise could suppress the immune response. This was down to what was known as the ‘open window theory’ in which there’s a short period of time directly after exercise during which the immune system was weakened.

This is because levels of T and natural killer cells seemed to be lowered directly after intense periods of working out. But more recent thinking is that they’re not really lowered – they’re just rushing around the body in the blood stream, where they can better do their jobs of neutralising those harmful pathogens.

This comes with a caveat, though: it is possible to weaken your immune system by overtraining. Physical activity raises your cortisol levels, small amounts of which are good for your immune system. However, high levels over a prolonged period mean your body goes into chronic stress, at which point it becomes an immunosuppressant.

This doesn’t mean that you shouldn’t train hard, only that you should build up slowly and make sure you balance long rides with sufficient recovery time.

Prof Florida-James again: “Like all training, if you build up slowly and allow your body to adapt to the stress of the ride lengths increasing, then it will react positively. If, however, you build up too fast, constantly taking your body into the red zone and not allowing enough recovery, then you can be more susceptible to bugs.

“It’s about getting the balance of activity – intensity/duration/frequency – and rest/recovery right to get the most benefits from the activity itself in strengthening the immune system.”

The holistic approach

However, there’s more to health than cycling – yes, really. For a really healthy immune system, you should aim to improve your diet and get plenty of sleep too. You’ve probably heard it before, but the Mediterranean diet really is good here: plenty of fruit and veg and healthy fats. Prioritise rest and relaxation too.

Says Prof Florida-James: “You need to ensure you have a well-balanced diet, in particular that calorific intake matches what you have expended, particularly following longer rides. Sleep is extremely important too; it is an active part of recovery and another key factor in the jigsaw of staying healthy and keeping on top of your activity.”

“There is no magic bullet out there that keeps our immune system functioning well, rather it is a combination of different factors that we need to attend to, on an ongoing basis, that will give us the best chance of staying healthy.”