≡ Menu

The Heat Takes Its Toll

Wilco Kelderman

It’s been infernally hot on the Tour de France with the temperature in the shade reaching 39°C (102°F). Only the riders can’t sit in the shade they must race in the open. Reports said riders drank up to 20 bottles each during yesterday’s stage.

Thirst and heatstroke are obvious factors but the heat takes its toll in many ways.

Hot air: When we talk of heat it commonly means the air temperature cited in forecasts. This is the shade temperature and on the open road the temperature is often much higher. The black tarmac soaks up the heat and can be 60-80°C, enough to cook an egg. So on a day without a breeze the air above it gets heated by convection to 40-50°C. But this is only the start of the problems.

Radiation: if the road heats the air it also radiates back the heat. The same on a climb cut into the site of a mountain where the rock face on one side of the road radiates heat back. The amount depends on the exposure to the sun, the type of rock (or concrete) and other factors but it’s noticeable. There’s also the direct effect of the sun too as it beats down on riders. When pedalling there’s a draft meaning this isn’t so obvious but it’s there. Sunburn is a concern, there’s the long term worry about skin cancer but short term reddened skin means precious blood is being diverted from the muscles to the damaged dermis.

Chris Froome

What to do? Ride. The air flow from riding is cooling than standing still but this is because you sweat. Sweat is an essential body function but not without its problems. All that water has to be replaced and riders were consuming 15-20 bottles each yesterday. The easy part is squirting it into your mouth, getting it through the intestines into the rest of the body can be fatiguing. The drink needs to be right too, riders will take bottles of water to drink and spray themselves and bottles with energy drinks containing salts to replace the minerals sweated out. Often there’s a small “x” written on the bottle to mark the difference so nobody sprays themselves with a sticky sugary drink.

Someone has to go and fetch all this water. This year Michał Kwiatkowski has been a star water carrier. Dropping back to the team cars is never as easy as it looks, there’s the added distance of going back and forth between the peloton. The effort is hard, it can look easy riding back to the peloton but take yesterday’s stage when Giant-Alpecin were doing through and off, a rider trying to get back to the bunch must work harder than the bunch and with less aerodynamic assistance, all while carrying several bottles. So simply getting the water is tiring. For the breakaway the Tour has a special moto fraicheur with a rank of bottles for the riders to collect if they can’t get a team car and on a hot day the rule about not being able to get food and drink from team staff in the first and last 20km is relaxed. If all else fails out comes the can of Coca Cola.

Returning to sweating, it involves losing a lot of water but also minerals. Sometimes you can see the salt marks on jerseys and the straps of helmets. There are tests to measure who sweats what as it varies, you could be a big potassium loser and someone else runs out of sodium fast. There’s also the pain from the salt going into open wounds, not severe but it just adds to the discomfort. Sweating into the pad of your shorts can make them uncomfortable and saddle sores can develop too.

Water is also lost from the lungs. You might see your breath condensate on a cold winter’s day but that’s because the cooler air makes it visible. Every breath sees you expire water and breathe hard for exercise and you lose more. The amount isn’t huge but estimates say 75ml an hour is possible, so over a stage that’s another bidon gone.

Body type makes a difference. Evolutionary theorists think one reason for our development was learning to walk upright. The theory goes on a hot day on the plains of Africa an upright human presents less surface area to the sun compared to, say, a crawling chimp and so an advantage for hunting and foraging on a hot day. Back to cycling and having a large surface area can help with cooling. The twiggy build of Chris Froome or Robert Gesink can be advantageous compared to the bulk of André Greipel or John Degenkolb.

Adaptation helps. BMC Racing saw the forecast for Utrecht and a heatwave and so had Rohan Dennis train during the hottest times of the day. After crashing out of the 2011 Tour de France Bradley Wiggins rigged an indoor trainer in a shed and used heaters to recreate the warmth of Spain rather than the chill of England before the 2011 Vuelta. For more on adaptation, try the BJSM podcast on the subject of heat illness.

Some teams use ice vests, waistcoats lined with pockets containing a gel that has been in the freezer. These have been used for “warm-ups” prior to the race, the idea being that the rider spins the legs on a trainer but the vests are used to keep the upper body at a more acceptable temperature. They’re also used for the post-race cool downs too, you can see Robert Gesink sporting one above. There are ice baths and and even cryotechnology. Once thought to help swollen muscles, the literature is inconclusive but The effect on core body temperature is proven and riders reporting they feel cooler and even sleep better for it.

UCI Protocol: new for 2015 is the UCI’s Extreme Weather Protocol which is meant to think of rider welfare when the weather is hard. But there’s not much to it, there’s no “wet bulb” limit like they use in marathons, just a pledge to hold a meeting if the weather is unusually hot or cold.

Forecast temperatures of 35°C sound hot enough but it’s way hotter out on the road. The tarmac can be burning hot and radiates it back to the riders to make for an infernal workplace. All this before stuffy hotels and apparently the aircon broke on Bretagne-Séché’s team bus.

Riding and sweating means you can still race when the air temperature exceeds body temperature but it’s hard with intensity and duration. This puts a strain on the body and it’s not easy to ensure the right balance of water and electrolytes, get it wrong and performance can drop, perhaps in the last hour of the race but also over days of sweating for hours on end; too much salt and the body can balloon up with water.

Drink, drink, drink say the team managers but the more tired a rider, the less they care. If a rider is consuming 20 bottles in a stage someone has to go and fetch a lot of it. But what if the hardest part was trying to do all this while riding past thousands of people sat in the shade with their picnic ice boxes filled with cold drinks?

Comments on this entry are closed.

  • BB Saturday, 18 July 2015, 12:54 pm

    Re Extreme Weather protocol – Do you know how many times a meeting has been called?

  • Anonymous Saturday, 18 July 2015, 1:39 pm

    Only caught highlights of stages this year but I have not seen the Coca Cola motorbikes?

    • The Inner Ring Saturday, 18 July 2015, 5:50 pm

      Coca Cola stopped sponsoring the race years ago, the repeated doping scandals put them off.

      • Andy Fla Sunday, 19 July 2015, 7:01 pm

        And yet they still sponsor the World Cup after the fifa scandals- interesting

  • Worzel Saturday, 18 July 2015, 2:00 pm

    I’m currently following the Tour live in France (and proudly sporting my Inrng cap) and we’ve been seeing temperatures in the shade on the climbs in excess of 40 degrees. I spoke to Alex Dowsett when he and Zak Dempster abandoned on the top of the Portet d’Aspet and they were both so drenched in sweat it was as though they’d just come out of a shower.

    Currently sat in Millau, the wind is building and there are plenty of rolls of thunder around so the peloton may get a cooling shower or two (just to make the roads extra slippy). Just hope the thunderstorm doesn’t stop my ride in to “The Rider” territory later.

  • MD Saturday, 18 July 2015, 2:23 pm

    At risk of repeating myself from previous ‘heat’ conversations – I work in a high temperature / humidity environment day in / day out which is regulated by using a wet bulb measurement. There is a ‘working rumor’ that once you suffer from dehydration and have recovered using several IV bags you can circum to dehydration more readily in the future (within the next couple of months). I do not know if there is any science behind this, kidneys might take longer to recover? But it does tend to ring true…..possibly the elongated period of this hot weather could effect riders again and again.

    And serious dehydration is life threatening. Vomiting is just a start, the head to toe body cramps and possible brain damage, it is also something the majority of people do not realise they are suffering from until it is too late!

  • Special Eyes Saturday, 18 July 2015, 4:07 pm

    An informative, and sobering, piece of writing this.
    It really does explain why attacks on the GC are so difficult at present. Add in a headwind, and it becomes virtually impossible.

    It also illustrates how important sports science, tailored to each individual rider, is.
    Personally, I think that this is where Sky are gaining the edge.

    • bb Sunday, 19 July 2015, 5:29 am

      Given Sky’s mantra of marginal gains & their uptake of the latest technological advances I’ve always been bemused by their choice of a predominately black kit. I’m no physics graduate (& I’m ready to be quickly corrected), but believe that black absorbs the most amount of light which then leads to a greater retention of the heat generated by sunlight. I remember last year Sky paraded in the media a lighter & sheerer jersey but I’m not sure if they actually raced in it. Perhaps this was an attempt to mitigate this heat issue. Whether their black kit is a problem or not at the least the riders should feel comforted by the view that black is more flattering for your figure!

      • Francisco Sunday, 19 July 2015, 12:26 pm

        It is a bit more complicated than that. Dark clothing is warmer for a static situation but add movement and the forced convection takes most of the heat away. Furthermore, for sheer fabrics, more radiation reaches the skin under white than under black clothes, think of light reflecting between fibres and reaching deeper.

      • Ed Monday, 20 July 2015, 12:46 pm

        Hi bb In this podcast with the CEO of Rapha (sky’s kitmaker) He explains how the black kit is treated with a chemical which makes it the equivalent of white when it comes to heat reflection. Clever stuff!


  • Chris Saturday, 18 July 2015, 5:43 pm

    The heat can also affect the road conditions. Think back to Beloki in’03. That’s a pretty extreme example however. On a hot day the sun can soften tar and fresh pavement. The effect is pretty minimal but if you’re already having a bad day it can feel like you are stuck in a tar pit about to become fossil fuel.

    • mjc Sunday, 19 July 2015, 6:48 am

      I’m not sure about the roads in France, but here in the States, especially in the Rockies and the NW, there are patches on the road to seal up cracks and expansion joints. That tar that fills them turns into a hot goo on super warm, sunny days. Those “tar snakes” become treacherous when you turn hard on them expecting to retain traction. You can even pull it out and mess with it like playdough.

      As for Sky’s black kit – makes me think it is better to look good then feel good (thank you Father Guido Sarducci). But those things are so thin, they can’t be absorbing much and certainly not providing much if any UV protection.

      • Special Eyes Sunday, 19 July 2015, 7:31 am

        That is an excellent point about the Sky mesh kit. I recall seeing a picture of Chris Froome’s mottled sunburnt torso, where the sun had burned him right through the kit.
        The riders obviously can’t wear skin cream as that would be sweated off quickly.
        The skin cancer risk is a valid point.

        • Andy Fla Sunday, 19 July 2015, 7:04 pm

          “The riders obviously can’t wear skin cream as that would be sweated off quickly.”
          I wore kids factor 50 in the Alps a few years back to do the Marmotte – 12 hours in the sun, temps of 39 deg at the bottom of the Telegraphe and no change in skin colour at all, so it is possible

      • Larry T. Sunday, 19 July 2015, 8:03 am

        Black (other than shorts) never made much sense to me either. The punters who wear the SKY team stuff reduce their visibility on the road as well, but looking good is more important than anything else to some folks. The mesh tops and plunging necklines of some of these modern kits make me wonder when the lace bits will be added for the full “boudoir” effect? 🙂

        • Anonymous Sunday, 19 July 2015, 10:45 am

          White shorts look terrible

        • J Evans Sunday, 19 July 2015, 7:12 pm
          • Francisco Monday, 20 July 2015, 1:00 am

            I’m sorry to point out that the article you linked to is utter nonsense. It mixes up two very different things: short wavelength (visible) radiation such as sunlight and long wavelength (thermal) radiation such as from body heat. The reflection of sunlight is affected by colour, but for thermal radiation all colours are essentially ‘black’. The corresponding material properties are the surface reflectance and the surface emissivity. Only polished metallic surfaces deviate significantly from aa black body in their emissivity.
            In spite of that, black clothing is not always warmer. For one example, see my earlier comment above.

          • noel Monday, 20 July 2015, 11:07 am

            thx Francisco… I love this blog partly because it seems to attract folk who actually know what they are talking about and not just armchair pundits who like the sound of their own voice (like me!)

          • Ed Monday, 20 July 2015, 12:48 pm

            In this podcast with the CEO of Rapha (sky’s kitmaker) He explains how the black kit is treated with a chemical which makes it the equivalent of white when it comes to heat reflection. Clever stuff!


  • Larry T. Saturday, 18 July 2015, 6:12 pm

    Good piece! Here in Italy we’re enduring what’s been called the hottest July in 150 years, though I can remember 2003 being plenty hot. Thankfully our tours are now in the high mountains but it’s still odd to be atop the Passo Stelvio in shorts and short sleeves in total comfort, if not feeling a bit warm. We’re lucky our HQ has excellent A/C, though “warmup” rides in the Monferrato countryside take on a new meaning! As for LeTour, it’s great to hear guys like Quintana and Nibali say it’s not over yet. Froome and Co. may be duplicating their earlier victory where they were almost outta gas by the end? I think a few are hoping to take advantage this time round.

  • Special Eyes Saturday, 18 July 2015, 7:09 pm

    There seems to be a lot of riders taking sticky bottle penalties.
    I know bottled water can be expensive but c’mon, 150 Swiss Francs is taking the **** !

    • Cameron Isles Sunday, 19 July 2015, 12:35 am

      I sometimes reckon you see more sticky handovers nowadays than clean ones @Special Eyes. Most of these guys commit the professional foul and motor-pace back in if they have a mechanical too. I remember when Froome crashed last year four or five Sky riders motor-paced back dangerously close to the team car as the others sped towards Carrefour de l’arbre I think it was. This year the contrast to the golfers at the Old Course couldn’t be more stark. It would be like watching Jordan Speith’s caddy mark his ball for him, clean it, and then place it back six inches in front of the coin, with a camera right there;-)

  • Kluszczynski Marc Saturday, 18 July 2015, 8:37 pm

    If it’s hot, we certainly must drink, but not too much! The risk of hyponatremia is not too far. Please read the Science of Sport article: Sport drinks, sweat, and electrolytes, part I, Dr Ross Tucker. In fact, hyponatremia occurs when we want to replace the amount of water we’ve lost by sweating. Tucker recommends to listen to one’s body and drink only if we need. Expensive salt solutions doesn’t prevent hyponatremia, which gives dizziness, cramps and may lead to death by brain oedema (an english triathlete of Ironman Francfort died on july 5th). So if water improves performance and is dangerous for health, is it a doping product?

    • The Inner Ring Saturday, 18 July 2015, 9:02 pm

      A good point… but a difficult one. If we recommend that drinking too much is a risk, which is true, it can lead to some people not to drink enough because they fear this risk and so they end up dehydrated and suffer the consequences. As you say thirst is useful but during a long effort it’s easy to lose this sense just as you can lose reaction times and other important things when tired or dehydrated.

  • RonDe Saturday, 18 July 2015, 9:20 pm

    There is a further cooling strategy which riders from a number of team are reporting: ride for Team Sky. The amount of phlegm from the roadside coming your way if you are in the famous black and blue is sure to aid cooling.

    Not that I think those contributing in this way are remotely noble in their intentions.

  • Anonymous Saturday, 18 July 2015, 11:20 pm

    Who would be a pro cyclist? the working conditions are awful.

  • Anonymous 2 Sunday, 19 July 2015, 1:18 am

    The fandom conditions are not much better, even on a sofa; this sport is a love hate relationship for all of us. Even without Kirby’s proclivity to ultimo km yelling and and Phil’s regular senior moments to distract us from the, yet again, non-human performances we’ve glimpsed this year.

  • Skippy Sunday, 19 July 2015, 8:45 am

    Many will recall tat Horny suffered P. E. after a TDF crash some years back ?

    Are Teams monitoring the Racers for this possibility ?

    Having suffered a repitition in February 2011 , in a time of year that i should have thought there was litle risk , i am hearing of several DEATHS locally in Tirol , from this cause !

    Whilst many think thez have a CRAMP , are they overlooking the possibility of a CLOT moving through their body ?

    Disgusted to hear of French fans helping cool off Froome , with their Urine . Ghandi maz have enjozed drinking his , but i doubt Chris relished the continual smell ?

    Was the EuroSport clip of Porte discarding Bidons , just after he was punched ?

    • Anonymous Sunday, 19 July 2015, 9:11 am

      No, that was a few days ago. As far as I know, Porte had a puncture.

  • SuperDom Sunday, 19 July 2015, 8:52 am

    At the Australian Championships a few years back, it was extremely hot, around 40 degrees C. Mid-race onwards I kept seeing riders go past with things around their necks. Scarves I thought? to stop sunburn? I later learnt they were women’s stockings/panty hose stuffed with ice cubes being handed out by the teams.

  • weeclarky Sunday, 19 July 2015, 8:55 am

    i don’t know how they cope with sweat running into their eyes, and all over their shades.

  • Polarbear Sunday, 19 July 2015, 9:59 am

    Hey,you can do something about this heat problem and improve your quality of life in that perspective. Pack a wind proof parka and a sweater, come to Norway and enjoy the Article race in August 🙂

  • Polarbear Sunday, 19 July 2015, 10:01 am

    I mean the Artic race, of course! (Damn autocorrect = autowrong!)

  • Jerome Sunday, 19 July 2015, 11:38 am

    Does a rider who slows down for the team car then accelerates back to the peloton actually cover more Km’s? Without turning around and riding the course backwards I would have thought they were still covering the same distance but as mentioned at an interval session type pace rather than a constant effort

    • ccotenj Sunday, 19 July 2015, 3:03 pm

      yea, i’m struggling a bit with that one too… short of literally turning around and riding back to the car (a real no-no), i’m not understanding how they are covering more km?

      i DO know one thing… i wouldn’t want to be the bottle guy on a day like that…

      • The Inner Ring Sunday, 19 July 2015, 3:13 pm

        It’s figurative of course. In the bunch it’s sometimes called a “return journey”.

        • ccotenj Sunday, 19 July 2015, 5:36 pm

          gotcha. thanks for clarifying. 🙂

  • Arlene Foley Sunday, 19 July 2015, 4:27 pm

    I am totally new to watching The Tour and hope someone can clarify for me, why oh why aren’t the guys in the top 5 not trying to attack Chris Froome except at the end of the race?? Why not try and get in the break away early, or take turns wearing him down during the whole race instead of at the end only?? I’m sure seasoned devotees are rolling their eyes but I don’t get it, is the 3 minutes so overwhelming they are giving up??

    • ccotenj Sunday, 19 July 2015, 5:47 pm


      they’d never get into the break, sky (and others trying to protect their positions) would chase them down (not to mention the break wouldn’t “let” a gc contender stay in the break, as they know they’d get chased)….

      as far as “take turns wearing him down”… again, all the riders have their interests in mind, and attacking in such a way leaves open the possibility of big losses because they would be likely to run out of gas by wearing themselves out…

      keep in mind, it isn’t “the entire tour” vs. froome… everyone has their own priorities…

      lone long attacks by gc riders almost never work (if they can even get away in the first place), which is why andy’s ride from a few years back stands out…

      bottom line… it is almost certainly a losing strategy to attack too early…

      • Pierre-Jean Sunday, 19 July 2015, 10:52 pm

        The question is better than the answer. I wonder what Louison Bobet would answer if he was still around.

        • Paul Jakma Monday, 20 July 2015, 1:46 am

          Don’t have to go back that far. Even the days of Hinault and LeMond saw multi-minute gaps won and lost across stages, IIRC.

  • Whale Oil Beef Hooked Monday, 20 July 2015, 5:45 am

    To anonymous 2 above. Quite clearly all performances are, yet again, human in this tour as humans are delivering them. Please let us know which riders are doping, what products and how specifically their alleged nefarious practices reduce their requirement to sweat or rehydrate?

  • Whale Oil Beef Hooked Monday, 20 July 2015, 5:45 am

    To anonymous 2 above. Quite clearly all performances are, yet again, human in this tour as humans are delivering them. Please let us know which riders are doping, what products and how specifically their alleged nefarious practices reduce their requirement to sweat or rehydrate?

  • treberden Monday, 20 July 2015, 12:26 pm


    I remember when I was a kid watching the TDF on the side of the road an “arroseuse” (rolling cart ?) was cleaning and refreshing the road between the caravane and the peloton.

    Not a wonderful help, but may be a little improvement to this heat problem !

    • The Inner Ring Monday, 20 July 2015, 1:14 pm

      It is still used but can only clean and cool the road a little. Spray water on the Tarmac today and it evaporates as you watch within seconds.

Next post:

Previous post: