Want to win the Tour de France? No worries, simply mimic Jonas Vingegaard, shrink to sub-60kg, generate upwards of seven watts per kilogramme up the toughest climbs and inflate your aerobic capacity to over 80ml/kg/min. Okay, banish those thoughts. But don’t banish cycling as cycling delivers myriad benefits beyond wrapping you in yellow atop a Parisian podium.
Here, we delve into the physiological boost cycling delivers across the performance spectrum, from the occasional cyclist to those of you who train for behemoths like Etape du Tour and Maratona dles Dolomites. We’ve sought input from Dr Garry Palmer, founder of Sportstest, a cutting-edge performance centre based in the West Midlands. “That’s great,” you might ponder, “but Palmer’s clearly about the high-performers. What does he know about the part-time pedallers?” A fair bit, as it happens…
Read more: Pros vs amateurs: exploring the difference in physical performance
“Five years ago, I’d say nearly 100% of my clients were performance focussed,” Palmer says. “Now we’re looking at around 50% with the other 50% more about improving health. It’s very much been driven by Covid, as people are far more aware of their well-being, both physical and mental.”
Right, onto how cycling will make your life a healthier one…
“Anything that raises your heart rate from a health perspective is a good thing,” Palmer explains. “Your heart muscle grows stronger and you develop a greater ability to carry oxygen to the muscles. These are just two key reasons why this is a good thing. In turn, this reduces the chances of many cardiovascular-related diseases.”
For the casual cyclist, this can mean cutting the risk of coronary heart disease by 18%, according to a study in the British Journal of Sports Medicine. Another study in the Journal of the American Heart Association reported that even occasional cycling can lower the chances of hypertension.
The cardiovascular benefits are understandably more pronounced for committed cyclists with research in the Journal of Applied Physiology showing that elite cyclists possessed significantly larger hearts than amateurs. This results in greater stroke volume and reduced resting heart rate – both conducive to increased endurance and accelerated recovery not only between rides but also between hard efforts.
Stroke volume’s influence on performance is worth a slightly deeper dive. An average person’s heart weighs around 300g; a good recreational rider’s might be 500g; racing the Tour and that could reach 800g-1kg. This growth is partly down to a thickening of the chamber walls but heavily down to an increase in heart-chamber size, which blows up like a balloon.
And that’s important because chamber size influences stroke volume, which is the volume of blood pumped from the heart with each beat. During exercise, your heart pumps at around 70% efficiency. Say the heart’s filled with 50% blood, we’re talking around 150ml for the 300g heart, which means pumping out 105ml with every beat. For a good amateur and their 500g heart, that 50% equates to 250ml so around 175ml blood delivered with every beat. As for a pro, we’re looking at a seismic 280ml of blood with every beat.
This then impacts cardiac output, which is the amount of blood pumped out each minute. Say the ‘average person’ and good amateur are riding at 130bpm, the cardiac output is 13.65l and 22.75l blood pumped out per minute, respectively, for the two cyclists. As blood carries the oxygen and nutrients that serves your working muscles, you can begin to see how a bigger, stronger heart can lead to significantly improved cycling performance.
“A little bit of weight management, a little bit of fat burning. They’re solid reasons to mount a bike from an activity point of view,” says Palmer. “Burning calories is a good place to start. As long as your daily caloric input’s fewer than your output, you’ll lose weight. And if you’re carrying less weight around, you’re less susceptible to traditional metabolic diseases like heart attacks, high blood pressure and diabetes. So, some kind of cycling a few times a week, without flogging yourself, is a good idea.”
Cycling’s a cardiovascular form of exercise, meaning it triggers the body’s fat-burning mechanisms, resulting in shedding unwanted pounds. In fact, a study in the Journal of Obesity found that cycling at moderate intensity for 30 minutes per day, five days a week, resulted in significant reductions in body fat and waist circumference in overweight and obese individuals. That sounds a lot but is a 15-minute commute to work.
Even a daily commute by bike can contribute significantly to weight loss (Getty Images)
At the other end of the performance spectrum, weight – or lack of it – is arguably more about ascending a hill or mountain quicker than the health implications. Lighter generally means faster as long as there’s no drop in power output. According to the American Council of Exercise, professional cyclists tend to between six and 10% on the men’s side and 14 to 20% on the women’s. For good recreational riders, you’re looking at around 13 to 18%; women at around 8 to 24%.
Both levels of rider should be interested in the ‘fatmax’ zone. This is the intensity at which the percentage of energy coming from fat is at its peak. Research suggests this is around 60% maximum heart rate for the unfit; around 70-75% for the fit. The higher this is, the harder you can work when using fat as the fuel. This is down to powerhouses in the cells called mitochondria. Through training, they swell in size, meaning they can burn greater amounts of fat with oxygen, so making you a more efficient cyclist. In fact, further studies suggest that fat usage may be 80% higher in athletes compared to the sedentary population.
Where things become confusing ties in with intensity as while cranking up effort taps into the more easily accessed carbohydrates, you might still burn more fat calories. You see, cycling above your fatmax might burn a lower proportion of fats compared to carbohydrates, but the overall calorie burn is higher, of which the overall fat-burnt calories might come in slightly higher, too.
Higher-intensity exercise has also been proven to improve the efficiency at which you carry oxygen around your body. In essence, a bout of higher-intensity efforts will make you more efficient, again meaning your body will burn more fat at higher intensities. Finally, you’ll enjoy a raised metabolic rate. Interval training strains your muscular system more than ‘fatmax’ sessions. The new, lithe you will burn more daily calories because muscle mass is metabolically more active than fat tissue.
Just remember that experienced riders can absorb higher-intensity work than occasional riders, so choose your efforts wisely. Actually, while we’re on the topic of intensity and physiology, the performance-seekers out there might ask how many hours a week you should train for to enjoy peak performance? This, says Palmer, is an incorrect reductionist approach.
“I have a physiology book – I think by [noted exercise physiologist] Tudor Bompa – that you need to train 20hrs a week to be an elite, 12hrs to be a good recreational athlete… I’ve always thought that was rubbish. If your 12hrs a week isn’t at the right mix of intensity, with the right recovery, you’ll end up in a hole. Someone ticking off for 4hrs a week of effective training could give them the same outcome.”
“It’s about training, overload and recovery,” adds Palmer. “And this is highly individual. You might respond differently to a functional threshold of power (FTP) session than me, which means recovery time is different. This is where a fitness test comes in. That said, there are things we can all do to recover more proficiently. How well have you slept? How well have you eaten? Do you use compression tights? Do you stretch? I know 50-year-olds who recover just as well as 20-year-olds. All of this comes down to your individual physiology.”
Lungs like bellows
Cycling doesn’t just work wonders for the heart and muscles; it’s also beneficial for the respiratory system. As you pedal, your lungs work overtime to absorb and assimilate the oxygen it needs to fuel your muscles.
At a casual riding level, you’ll enjoy improved lung capacity and respiratory efficiency; in other words, you’ll more efficiently take in oxygen and expel carbon dioxide, resulting in easier breathing during everyday activities and reducing the chances of respiratory illnesses. To that end, a study in the European Journal of Applied Physiology showed that cycling improved lung function and respiratory muscle strength in sedentary individuals.
The more effectively you train, the greater lung capacity and efficiency you'll gain (Craig Zadoroznyj/SWpix.com)
Crank up to the next level of competitiveness and you’ll enjoy even greater lung capacity and efficiency of gas exchange. In the performance amphitheatre, this means a greater VO2max to keep you riding harder for longer.
Strengthen your immune system
Cycling also bolsters your immunity. How isn’t 100% clear but studies have shown that exercise increases the production of macrophages, which are white cells that attack the bacteria that can trigger an upper respiratory disease.
Regular cycling also lowers the levels of stress hormones in the blood, like adrenaline and cortisol, and there’s a clear link between stress and reduced immunity. That doesn’t just manifest itself in physical well-being but mental, too. Exercise releases endorphins, which are chemicals in the brain that are the body’s natural painkillers and mood-lifters, and have been identified as a key hormone in the fight against depression. (As a further mental fillip, researchers at the University of Texas discovered that aerobic exercise – performed between the ranges 50-80% maximum heart rate – reduced symptoms of depression. The authors concluded that three sessions a week for around 45-60mins produced endorphin boosts high enough and regular enough to improve mood, self-esteem and energy levels.)
How does increased cycle fitness affect immunity? Well, a study in the British Journal of Medicine followed a group of 1,002 adults over a 12-week period and discovered that, on average, they experienced symptoms of upper respiratory tract illness (URTI) – a common cyclist’s ailment – for 21 days. However, those in the top 25% for fitness, who exercised for five days or more each week, experienced 43% fewer days with these symptoms (nasal discharge, coughing, fever…) and when they did display symptoms, they were less severe.
So, the more you cycle, the greater your immune system? Not necessarily and that’s down to the ‘open window’ theory. While consistent moderate cycling results in positive immune changes; in contrast, high-intensity exercise over 90mins has been shown to depress the immune system, which is when viruses or bacteria can gain a foothold. It’s another reason why you shouldn’t overload your training with high-intensity efforts. You should also enjoy regular carbohydrate feeding and hydrate well, as both are known to attenuate the impairment of immune function post-heavy exercise. Why is likely down to the reduction in blood glucose concentration and associated insulin and stress hormone response.
At all levels, cycling will also improve muscle definition, help you sleep, ease fatigue, make you happier and, according to one study, improve your creativity. “Ultimately, wherever you are on the cycling spectrum, your health will benefit,” Palmer concludes. “Just get on your bike and pedal.”
Cover photo by Olly Hassell/SWpix.com