A typical man is about 60 per cent water<\/a>. The average woman is roughly 55 per cent water because muscle holds more water than fat, which women usually have more of.\u00a0<\/p> This also means that endurance athletes, such as cyclists, will tend to store more water than a less lean person.\u00a0<\/p> Water is crucial for homeostasis \u2013 the way in which the body regulates itself to work properly.\u00a0<\/p> Normal bodily functions such as waste removal and temperature regulation are impossible without water.\u00a0<\/p> Dr Rodriguez-Sanchez, a lecturer in physiology and nutrition at the University of Stirling, likens the levels of water in our body to a \u201cbank balance\u201d.<\/p> \u201cWe are always losing water through breathing and sweat and replacing it with drink and food,\u201d she says.\u00a0<\/p> Failure to compensate for water loss leads to dehydration, defined as a decrease in the body\u2019s normal levels of water.<\/p> It causes \u201cchanges in cardiovascular, thermoregulatory, metabolic, and central nervous function that become increasingly greater as dehydration worsens\u201d, according to a 2007 article by Bob Murray in the Journal of the American College of Nutrition<\/em>.\u00a0<\/p> Being only slightly dehydrated on a bike ride is detrimental, says Dr Rodriguez-Sanchez.<\/p> \u201cIt\u2019s important we don’t lose more than two per cent of our body mass otherwise performance will be impaired,\u201d she explains.<\/p> Dehydration is usually measured as a percentage of body weight lost from water.\u00a0<\/p> So, a 70kg cyclist would want to avoid losing more than 2kg of body mass on a ride \u2013 two per cent of 70kg is 1.4kg, but some of the weight loss will be glycogen (stored carbohydrates<\/a>).<\/p> The negative impact on performance relates to an effective reduction in VO2 max<\/a>, an increase in our rate of perceived exertion<\/a> and possible increased risk of cramps.\u00a0<\/p> \u201cSomeone who is four per cent dehydrated won\u2019t be reaching their VO2 max \u2013 they might only be at 75 per cent of it,\u201d she says.<\/p> \u201cThey are more likely to feel exhausted and there is some association with higher cramp incidents.\u201d<\/p> Dr Rodriguez-Sanchez says losing more than two per cent can also put the cyclist\u2019s health at risk.\u00a0<\/p> \u201cFrom that loss of water, there\u2019ll be dizziness and if it\u2019s greater than four or five per cent, there is a higher risk of heat stroke,\u201d she adds.\u00a0<\/p> Will Girling, nutritionist at the EF Education-EasyPost WorldTour team, says there are several signs of dehydration.<\/p> \u201cYou may start to feel weak, nauseated, bloated or confused,\u201d he explains.<\/p> \u201cDeveloping muscle cramps, headache, slurred speech or swollen hands and feet during or after prolonged exercise can be symptoms of dehydration and hyponatremia, a severe loss of electrolytes.\u201d<\/p> Sports scientist Andy Blow, who is CEO of Precision Fuel and Hydration, suggests drinking one 500ml water bottle <\/a>an hour in mild weather and two per hour when cycling in hot weather<\/a>.<\/p> But everyone\u2019s sweat rate is different, so these generic guidelines aren\u2019t very useful.\u00a0<\/p> A better way to figure out how much to drink on a bike ride is to calculate how much fluid you lose.\u00a0<\/p> Bear in mind it\u2019s not necessary or desirable to replace all the water lost on the ride itself \u2013 just try not to lose more than two per cent body mass.<\/p> Overdrinking can cause exercise-associated hyponatremia (EAH). In this condition, sodium is diluted by water to dangerously low levels in the blood, potentially causing kidney failure and death.\u00a0<\/p> In a less serious scenario, Dr Rodriguez-Sanchez says: \u201cIt will impact our gastric emptying, which can make us feel uncomfortable during exercise.\u201d<\/p> Scientists have observed EAH in marathon runners who started a race overhydrated (some reported drinking 8-10 litres of water the day before) and drank a lot during it.\u00a0<\/p> On the other hand, you don\u2019t want to set out dehydrated.<\/p> \u201cSometimes it has been observed that mostly male athletes start their training sessions or their competition already dehydrated,\u201d says Dr Rodriguez-Sanchez.<\/p> Since men tend to sweat more than women<\/a>, pre-exercise hydration is particularly salient for male cyclists.\u00a0<\/p> Although not fail-safe, studies have found that urine colour is a decent proxy for hydration status.\u00a0<\/p> On Armstrong\u2019s urine colour chart (not that Armstrong<\/a>), lighter is better than darker.\u00a0<\/p> Instead of paying for a lab test, taking a DIY sweat test is free and still effective.\u00a0<\/p> Girling recommends the following protocol:<\/p> By comparing the results of the two weigh-ins, you can calculate your sweat rate during the ride.\u00a0<\/p> For example, if you weighed 65kg before a two-hour ride and 63.5kg after but drank a litre (1kg) water during the ride, then you lost 2.5kg of water, or 1.25kg per hour.<\/p> This is higher than two per cent, so you\u2019ll know you should\u2019ve drunk more. If you come back heavier, you\u2019ve certainly drunk too much.\u00a0<\/p> Dr Rodriguez-Sanchez recommends testing your sweat-loss rate at different temperatures and intensities.<\/p> During harder intervals<\/a>, your heart rate will be higher than on endurance rides<\/a>, so you\u2019ll breathe out more water. Your muscles will also produce more heat, requiring more sweat to cool you down.\u00a0<\/p> \u201cIn winter, we’re still losing fluid but we are not perceiving it as much as during the summer,\u201d says Dr Rodriguez-Sanchez.<\/p> \u201cWe’re losing water through our breathing. We are wearing a couple of layers and this technology in the fabric might have an impact on our sweat rate.\u201d<\/p> Another way to stay hydrated on a bike ride is to drink to thirst.\u00a0<\/p> Academics in favour of this approach cite evidence, including from a 2010 study by researchers from the University of KwaZulu Natal, that drinking as much as desired stops cyclists losing more than two per cent of their body weight in water.\u00a0<\/p> \u201cFor 99 per cent of people, it\u2019s fine to drink to thirst,\u201d says Dr Tim Podlogar, an exercise physiologist from the University of Birmingham.\u00a0<\/p> He is also a nutritionist at Bora-Hansgrohe WorldTour team. He doesn\u2019t recommend that riders match fluid intake with sweat rates and try to drink a set amount.\u00a0<\/p> Dr Podlogar adds that drinking to thirst prevents you from gaining weight during exercise from excessive fluid intake.<\/p> \u201cIf you’re sensible and you drink to thirst I think this just can’t happen because you will always end up your training session or your bike race lighter than you started it,\u201d he says.\u00a0<\/p> \u201cAnd I think the biggest problem is drinking more than what you sweat out, which is pretty hard to achieve.\u201d<\/p> However, Dr Rodriguez-Sanchez believes waiting until you\u2019re thirsty to drink leaves it too late.\u00a0<\/p> \u201cWhen we start feeling thirst, we are already dehydrated, so normally thirst will be triggered when we have already lost two per cent of our body mass through sweating,\u201d she says.\u00a0<\/p> Our experts\u2019 advice on drinking on a bike ride can be boiled down to the following points:\u00a0<\/p> Dr Rodriguez-Sanchez says elite runners and cyclists will sometimes lose a significant amount of weight during a race while maintaining performance.\u00a0<\/p> For example, a 2012 study published in the Clinical Journal of Sports Medicine<\/em> found that Haile Gebrselassie lost 9.8 per cent of his body weight in the 2008 Dubai Marathon. He won in 2:05:29.<\/p> \u201cThey might be performing well but that [weight loss] is putting them at higher risk [of heat complications],\u201d says Dr Rodriguez-Sanchez.\u00a0<\/p> That said, it is likely that a lot of Gebrselassie\u2019s weight loss came from glycogen stores he used while running at such a high speed.\u00a0<\/p> Blow recommends drinking a combination of sports drinks and plain water to replace the carbohydrates, salts and fluids you lose during exercise.\u00a0<\/p> He says: \u201cIn the Tour de France they\u2019ll drink a lot of energy drinks, as well as a lot of water and electrolytes separately.\u201d<\/p>![\"Fitness](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/39\/2024\/06\/GettyImages-1760627322.jpg\")
The effects of dehydration on cyclists\u00a0<\/h3>
![\"UAE](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/39\/2024\/06\/GettyImages-1535598120.jpg\")
Lower VO2 max, exhaustion and cramping <\/h4>
![\"Team](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/39\/2024\/06\/GettyImages-2151027017.jpg\")
How much should you drink?<\/h2>
![\"Beat](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/39\/2022\/08\/Beat-the-heat-08-e319700.jpg\")
![\"Urine](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/39\/2024\/06\/GettyImages-1499953450.jpg\")
Take your own sweat test<\/h3>
![\"Sweat](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/39\/2024\/06\/GettyImages-1525593105.jpg\")
Drink to thirst<\/h3>
![\"How](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/39\/2022\/07\/14-00-34SNY0520-b0a697c.jpg\")
Key cycling hydration tips\u00a0<\/h3>
How much weight is safe to lose during exercise?<\/h2>
What should you drink on a bike ride?<\/h2>
![\"Liam](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/39\/2024\/05\/AM9A0112-scaled.jpg\")