{"id":363777,"date":"2025-12-22T03:52:14","date_gmt":"2025-12-22T03:52:14","guid":{"rendered":"https:\/\/www.newsbeep.com\/au\/363777\/"},"modified":"2025-12-22T03:52:14","modified_gmt":"2025-12-22T03:52:14","slug":"this-is-what-happens-inside-your-body-during-the-toughest-rides-and-its-not-pretty","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/au\/363777\/","title":{"rendered":"This is what happens inside your body during the toughest rides \u2013 and it’s not pretty"},"content":{"rendered":"

Anyone who has really pushed their limits on a bike during an event will have experienced burning thighs, screaming lungs, a pounding heart and oceans of sweat.<\/p>\n

But have you ever wondered what is happening to your body when you pedal? And how you can energise it to ensure you arrive at the finish line in the most efficient way?<\/p>\n

We lift the lid on the physiology and psychology involved so you can leave the competition wheezing in your wake.<\/p>\n

Heart of the matter
\n\"\"Riders wait nervously on the start line of the 2025 L’Etape du Tour. A.S.O.\/Bastien S\u00e9on<\/p>\n

You\u2019re lined up on the start line. The nerves are cranked up, meaning your kidneys\u2019 adrenal medulla is stimulated into action and secreting adrenaline.<\/p>\n

It\u2019s the hormonal cause of that \u2018flight or flight\u2019 mechanism and results in a cascade of cardio repercussions before you\u2019ve even set off. <\/p>\n

\u201cThese include an increase in heart rate and cardiac output,\u201d says cardiologist Andre La Gerche. \u201cIt also leads to a rise in blood pressure and metabolism.\u201d <\/p>\n

Further adrenaline-fuelled physiological changes include the relaxation of the smooth muscle in the wall of the bronchioles, which leads to a better supply of air to the alveoli; an increase in respiration rate; and dilation of coronary blood vessels and those of skeletal muscle, thus providing increased blood supply to those areas.<\/p>\n

So, your body\u2019s started to prepare for the physical challenge ahead. But it\u2019s still a shock to the system when you pedal, especially if your ride opens with a high mountain pass. <\/p>\n

This is where \u2018oxygen uptake kinetics\u2019 comes into play. Essentially, this is the speed at which your body can deliver oxygen to working muscles from a state of rest and so click swiftly into a steady state.<\/p>\n

Not surprisingly, the fitter you are, the more proficient your system is at flicking the switch from one to the other, with distance runner Paula Radcliffe reportedly having the fastest VO2 kinetics of all time at 8-9 seconds.<\/p>\n

\"\"You can train your body to better combat immediate aerobic stress. A.S.O.\/Bastien S\u00e9on<\/p>\n

However, one study showed that recreational endurance athletes improved theirs by 30% after only six weeks of training. For this brief period, you\u2019re leaning heavily on the anaerobic system to generate energy without oxygen.<\/p>\n

When the oxygen supply meets demand, your aerobic system can sustainably power the effort at a constant rate (up to around 70% of your maximum heart rate).<\/p>\n

\u201cThe speed at which your heart beats is no different between elites and recreational riders,\u201d says La Gerche.<\/p>\n

\u201cNo matter how hard you train, you can\u2019t change that. But you can change its size. In general terms, the fitter you get, the bigger your heart is. A normal heart is around 300g \u2013 the size of a fist \u2013 while a Tour de France rider\u2019s is up to a kilogram.\u201d<\/p>\n

Consistent training thickens the heart walls and increases chamber size. This is important during your sportive adventure due to stroke volume, which is the volume of blood pumped from the heart with each beat.<\/p>\n

\u201cDuring exercise your heart has about a 70% efficiency rate at pumping out blood. A 400g heart can accommodate around 200ml of blood, which means you\u2019re pumping out around 140ml of blood with every beat,\u201d says La Gerche. <\/p>\n

\u201cProfessional cyclists\u2019 chambers fill with around 400ml of blood. Apply that 70% figure and that\u2019s 280ml of blood with every beat.\u201d<\/p>\n

Its importance becomes clear when you apply it to cardiac output, which is the amount of blood pumped out each minute. <\/p>\n

If both our recreational and elite examples are riding at 135bpm, the former\u2019s sending out 27l of blood each minute, while the latter\u2019s pumping out 54l.<\/p>\n

And as blood carries the oxygen and nutrients to serve your working muscles, you can see how a bigger, stronger heart can boost cycling performance. <\/p>\n

This benefits higher-intensity efforts, too, because that greater blood flow also means swifter recovery between efforts, such as when the ascent undulates.<\/p>\n

Which begs the question: during a tough ride, does your heart fatigue? \u201cAfter five or six hours of intense exercise, we can put an ultrasound on the heart and see that the heart is fatigued,\u201d says La Gerche.<\/p>\n

\u201cIt\u2019s easy to squeeze your leg muscles and see that they\u2019re sore. But the effect on your heart is underestimated because it\u2019s a silent partner. Just respect the challenge.\u201d<\/p>\n

\"\"Your heart can fatigue during a long, difficult ride. A.S.O.\/Jennifer Lindini<\/p>\n

As the day rolls on, your muscular system also suffers, especially if you push it well beyond what you manage in training. <\/p>\n

This is down partly to increasing the production of reactive oxygen species, or ROS, that results in oxidative stress in the blood and skeletal muscle itself.<\/p>\n

Essentially, it\u2019s down to the huge number of muscular contractions required to send you sky-rocketing over the next mountain and has been associated with accelerating muscle fatigue. <\/p>\n

It\u2019s also mooted to be one of the reasons behind delayed onset muscle soreness (aka DOMS). If you haven\u2019t trained as much as you\u2019d hoped, a well-balanced post-event diet, including antioxidant-rich fruit and veg, will help.<\/p>\n

Power carbs
\n\"\"Porridge is a shrewd choice on the morning of a big ride. Getty Images<\/p>\n

Why did our early ancestors eat each other? Because they saw each other as a nutritious snack, according to a 2017 study by James Cole, an archaeologist at Brighton University. <\/p>\n

According to Cole\u2019s calculations, the average human body contained 125,822cals. Much of that figure is down to fat\u2019s high calorie content, with 1g furnishing 9cals. Even a WorldTour rider, who weighs only 60kg and has 7% body fat, has more than 37,000 stored fat calories.<\/p>\n

So why do we bonk<\/a> in a sportive? Well, that\u2019s down to exercise intensity and the fact that you\u2019re burning predominantly carbohydrates to avoid being swept up by the broom wagon.<\/p>\n

\u201cYour most readily accessed carbohydrate store is muscle glycogen, which is mooted at around 500g or 2,000cals,\u201d says Tim Podlogar, nutritionist at Tudor Pro Cycling. \u201cRiding at a high intensity, you can burn through this in two-and-a-half hours.\u201d<\/p>\n

This is why Podlogar recommends filling up your glycogen stores the day before. \u201cThat means multiple meals that are high in carbohydrate and low in fibre,” he says, “easy-to-digest foods such as white rice, white pasta and even Haribos.\u201d <\/p>\n

Also, avoid a gentle ride late on the eve of your big day because that\u2019ll eat into your glycogen levels.<\/p>\n

When it comes to race day, a high-carb breakfast further boosts glycogen stocks. Porridge, a buttered bagel or white toast and jam are popular. <\/p>\n

And then it\u2019s riding time. Many of you will already consume gels<\/a>, bars<\/a> and energy drinks<\/a> in search of glucose replenishment, following a traditional 60-to-90g-an-hour strategy. You might be capable of more, however, especially if you’re one of the fitter cyclists out there.<\/p>\n

\u201cOur research shows that many amateur riders can handle 120g carbohydrate an hour,\u201d he says, which goes some way to compensating for the 6,000cals-plus burned during a long day in the saddle. \u201cAt an elite level, we had many riders at last year\u2019s Giro d\u2019Italia who were consuming way more than that.\u201d<\/p>\n

Feeding should start from your first pedal stroke and, according to Podlogar, comprise sugar from solids only, keeping fluids to water because separating makes it easier to monitor how much sugar and fluid you\u2019re consuming. You can go for an electrolyte drink<\/a>, albeit Podlogar says you can tick this off from most gels.<\/p>\n

But when should you feed to optimise the sugar hit? \u201cI recommend to my riders that they fuel well downhill. <\/p>\n

“You\u2019re not pedalling so it\u2019s easier to digest; the bloodflow to the intestines increases and so absorption improves.\u201d<\/p>\n

Three energy hits per hour \u2013 one bar and two gels, for instance \u2013 will boost your muscle glycogen levels. Not only should this prevent a sugar low, it could prevent muscle degradation, too. <\/p>\n

\u201cWe know that your muscle is damaged if there\u2019s insufficient glycogen around it; it\u2019ll break down protein to a higher degree from the muscle itself in search of energy.\u201d<\/p>\n

Core values
\n\"\"There can be little opportunity to cool down during a ride such as L’Etape du Tour. A.S.O.\/Bastien S\u00e9on<\/p>\n

Should your event be one of the big Alpine challenges, you could well be enduring temperatures over 30\u00b0C. <\/p>\n

That means you\u2019ll heat up like a nuclear reactor, which isn\u2019t great because a swathe of biochemical reactions and nerve conductivity are optimised at around the 37\u00b0C mark.<\/p>\n

But you can\u2019t argue with science or, more precisely, the body\u2019s inefficiency. \u201cIt\u2019s around 20% efficient at generating energy,\u201d says Chris Jones of body-temperature sensor outfit Core.<\/p>\n

\u201cThat means for every 5cals of energy you burn, only 1cal is used for mechanical work. The remaining 4cals are released as heat energy.\u201d<\/p>\n

This means you\u2019re almost combustible on steep ascents. Take WorldTour rider Simon Clarke, who Core monitored on stage 14 of the 2021 Tour de France, specifically a 100km stretch that included the ascent of the Col de Monts\u00e9gur: 4.2km at an average gradient of 8.7%.<\/p>\n

\u201cThis section and the following ascent up the Col de la Croix de Morts saw the fastest increase in Clarke\u2019s core body temperature, where it hit 39.2\u00b0C,\u201d says Jones. <\/p>\n

\u201cThe steeper the ascent, the faster the increase in core body temperature. This is because of the increased physical intensity and because there is less cooling from the wind at slower speeds.\u201d <\/p>\n

On the flipside, the rapid descent of Col de Monts\u00e9gur saw Clarke\u2019s core drop to 38.1\u00b0C, which was below what it was when he started the climb. <\/p>\n

This highlights that pacing is even more integral to reaching your goals when it\u2019s hot, although your body will try its best to lose heat via the same way it gains it, namely radiation, convection and conduction.<\/p>\n

Sweating is key to maintaining balance in the body. Around 580cals per litre of heat energy is needed to turn water from liquid to gas so it can evaporate from your skin (or your breath). <\/p>\n

So, whenever water leaves your body via evaporation, a corresponding amount of heat also leaves your body into the surrounding air, helping you cool down. So, it’s great for cooling but clearly not wonderful for your water stores.<\/p>\n

You can sweat over 1.5l an hour on a sweltering Alpine sportive. Covering those losses is difficult on two fronts: the practical side of drinking from a water bottle and the physical side of absorbing so much fluid. <\/p>\n

It might be manageable for an hour, but the deeper a rider digs into a ride, the more uncomfortable the gut becomes. If you can manage 750ml an hour, that\u2019s a good start.<\/p>\n

Again, training will help cool your engine because low aerobic fitness makes you more susceptible to heat illness. <\/p>\n

There\u2019s a strong correlation between an individual\u2019s aerobic capacity and their ability to offload heat. Studies show that if someone\u2019s working at half their aerobic capacity, their core temperature reaches around 38\u00b0C. <\/p>\n

If you and I do the same amount of work and you\u2019re twice as fit as me, your core temperature will be lower and you\u2019ll suffer less.<\/p>\n

Beyond training, acclimatise from home by having a 15-minute hot bath after a ride. Doing this five or six times in the final two or three weeks before your event will really help. <\/p>\n

\u201cDressing lightly will also help,\u201d says Jones. \u201cAnd keep it old-school by pouring water over your body and head. That can change your perception of the pain.\u201d<\/p>\n

Mental maths
\n\"\"Mental fatigue can harm physical performance. A.S.O.\/Jennifer Lindini<\/p>\n

It\u2019s not just your body that suffers during a sportive \u2013 your mind does, too, and you can be on the back foot from the start, according to a 2017 study, The Effects of Mental Fatigue on Physical Performance: A Systematic Review.<\/p>\n

The authors showed that seven of eight key studies \u201creported that endurance performance was negatively affected by mental fatigue, which was evidenced by a decrease in time to exhaustion\u201d. In short, don\u2019t cause yourself unnecessary pre-race stress or you\u2019ll be drained before the off.<\/p>\n

Of course, even the most diligent planner can see motivation drop when they\u2019re halfway up a mountain, miles from the finish line. <\/p>\n

This, according to round-the-world record-holder Mark Beaumont, is to be expected and he calls it the \u2018psychological arc\u2019. <\/p>\n

\u201cYou start fresh, dig deep at the end and finish strongly but there\u2019s that bit in the middle where you\u2019re far from starting and, in your head, far from finishing,\u201d he told us. This is true whether you\u2019re riding 50 miles or 500 miles.<\/p>\n

To ride the arc rather than sink in, try some psychological games. Chunking is one of the most common and involves breaking the event down into smaller, more mentally manageable chunks. <\/p>\n

If your next ascent features 10 hairpins, for example, tick off each hairpin. Many events supply a route sticker to smooth onto your top tube that can show natural chunks.<\/p>\n

Ultimately, the biggest driver of your mental state is motivation. Take a 2008 study by Professor Samuele Marcora that involved 10 rugby players cycling at a fixed power output based on 90% of their VO2 max<\/a>.<\/p>\n

When they could no longer maintain that wattage, he had them ride as hard as they could for five extra seconds.<\/p>\n

From an average power output of 242 watts in the test, despite apparent fatigue, they generated 731 watts.<\/p>\n

The results convinced Marcora that fatigue is no physical phenomenon \u2013 if it was, how could the cyclists generate such power when they\u2019d slowed down?<\/p>\n

Instead, Marcora says your decision to slow or quit stems from two key areas \u2013 motivation and perception \u2013 and lays the foundations for his psychobiological model of fatigue. <\/p>\n

When effort is perceived as maximal or when effort required eclipses the amount of effort you\u2019re willing to exert, then you stop. In essence, fatigue is an increase in time of perception of effort. <\/p>\n

Whether you agree with Marcora or not, one thing\u2019s clear: despite your body\u2019s suffering, it\u2019s the mind that\u2019ll often decide whether you reach the finish line or not.<\/p>\n","protected":false},"excerpt":{"rendered":"Anyone who has really pushed their limits on a bike during an event will have experienced burning thighs,…\n","protected":false},"author":2,"featured_media":363778,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[37],"tags":[64,63,538,137],"class_list":{"0":"post-363777","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-fitness","8":"tag-au","9":"tag-australia","10":"tag-fitness","11":"tag-health"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/363777","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=363777"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/363777\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/363778"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=363777"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=363777"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=363777"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}