A Long Hot Day – Racing in a Heatwave

If only the weather forecast was accurate. Riders in the Vuelta a España can look online or in the newspaper and see temperatures of 32°C (90°F) quoted for today… but these temperatures never reflect the reality of the road cyclist.

Instead the road is far hotter. This imposes a greater strain on riders who must drink many litres during the race. Here’s a look at the real temperatures and the ways to cope with the heat.

When the weather forecast lists temperatures these are temperature in the shade and therefore reflect the temperature of the air in a sheltered location. By contrast the cyclist cannot sit in the shade. The road heats up, a black strip of tarmac absorbs the heat from the sun very easily and by the time the race starts the road surface can easily reach 50-80°C (120-180°F). That’s just enough to fry an egg.

With the road so hot, the air above it is heated. So when the temperature in the shade is 32°C (90°F) it’s common for the cyclist to face infernal air temperatures of 40°C (104°F) or more, well above body temperature. In addition, heat is radiating from the tarmac and the sun itself is also heating the rider.

How to keep cool?
Ride. The mere act of pedalling ensures a breeze, meaning you can race in conditions where a marathon runner could not. The breeze itself does not cool, rather it is the evaporation of sweat. With exposed limbs and light fabrics the road cyclist can let the evaporation effect keep the body cool, or at least functioning, on all but the hottest of days. The only time this stops is when a rider climbs and there’s a tailwind. This means the rider is travelling at a similar speed as the air around them and so there is no breeze and therefore evaporation reduces.

That’s Ag2r’s Maxime Bouet saying he used 12-13 water bottles in yesterday’s stage, a record for him. That’s a lot… but not a record. Two years ago in the Vuelta riders were facing even higher temperatures and teams were handing out 240 bottles a day, on average more than 25 per rider. Of course it depends what is done with the bottles, whether they are used for drinking or get used to douse the rider in water.

Cold or hot?
Bedouin tribes in the Arabian deserts often take warm drinks despite the heat (although perhaps they just need to boil water to keep it clean?). A cold drink on a hot day can be the stuff of fantasy as the rider toils on a hot road. But the sudden ingestion of cold water can cause trouble for stomachs, whether cramps or digestive problems. But a cold drink can help bring the core body temperature down so it’s a question of what works for different riders.

A clever team will weigh riders before and after on hot days to get a quick take on dehydration. If a rider loses too much water then this reduces performance but at the same time it’s hard to constantly drink on the bike for hours. As fatigue sets in, drinking has to become a more concious effort. Here some try a mix of different drinks, plain water, then fruit juice and some with electrolytes, and when all else fails, a can of Coke emerges from the icebox in the team car. In the Tour de France, one Dutch rider was even spotted with a beer.

Some teams have been experimenting with ice vests, small waistcoat-like items of clothing 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. But Sky and Garmin have tried adapted versions during mountain stages, a high tech version of the old-school trick of putting sponge under the jersey, behind the collar, so that it drips water.

Adaptation also helps. Riders can get used to the heat, whether from a week’s stay somewhere hot or with more unconventional means. Last year Wiggins set up an indoor trainer in a garden shed and used heaters to recreate the warmth of Spain inside his English home.

Stopping a race doesn’t mean a rider cools down, especially as the finish line is often bustling and hot and the rider is standing in sweaty, salty clothing. Some teams are using static trainers to cool down but before this they’ll have a cool drink, maybe a wipe with a damp towel and other means.

Ag2r keep their cool

It can take longer to cool down properly. A cold bath is a simple remedy to help bring down core body temperatures. Teams use ice baths and and even cryotechnology but the aim of these techniques is to help swollen muscles. Although on a hot day many riders welcome the cooling effect too, in fact some said it was the most pleasant aspect.

There are more direct health risks. Melted tarmac can be a problem too. The tar used in road construction begins to soften and slowly the gravel chips sink into the tar and after a while the tar pools on the surface. This dark black material soaks up eat even more easily and liquefies in the sunshine… but only just. But it’s the equivalent of a cartoon character running into a patch of treacle on the road, the dense and sticky tar can catch a rider by surprise on a descent. It was a big factor behind Joseba Beloki’s 2003 crash in the Tour de France. In recent years the Tour de France has deployed a water tanker to spray sections of road prone to melting to help cool the tarmac.

Can it be too hot?
Races can be cancelled because of snow and ice, can they be cancelled because of excess heat? Yes, because the organisers have a duty to protect a rider’s health but there’s little definition to this idea. A pro race with experienced riders and team cars stocked with drinks is different from an amateur event where perhaps a lower threshold could be considered.

Exercising in the heat can be dangerous but the efficiency of cycling on a road means physical effort can be tolerated because the effort spent making a rider move fast and creates a good flow of air to help cool the body via the evaporation of perspiration. Today’s clothing is a great help.

It doesn’t make it easy but teams have mechanisms in place to help cope with the heat, from simple things like a following car stocked with drinks to ensuring riders often train in warm areas. There are more sophisticated techniques with ice vests and cryotechnology which can help with performance. Sports science literature lists solutions but note teams are often, but not always, ahead of academics.

Some like the heat, some don’t but it’s a technical challenge to overcome, just like other conditions experienced in the year, from racing through snow to learning to ride in a crosswind.

26 thoughts on “A Long Hot Day – Racing in a Heatwave”

  1. I rode up Alpe D’Huez a few weeks ago at midday in ridiculous heat. Having cycled it a handful of times in cooler conditions I was shocked to get to the third hairpin with a tongue like a dry sponge and legs of jelly. What a mess. I made it up in the end but only after a few impromptu showers in the streams running down the mountain. I was put firmly in my place.

    Interestingly, a friend of mine on the same ride who is ordinarily an honourable lantern rouge took it all in his stride. He rolled past me with a cheerful grin like he was wearing one of the ice jackets mentioned above. It’s possible he was better hydrated or maybe he’s found his sporting niche.

    • Maybe his more measured approach suits the added effort better. It’ll have cost you more to keep a “fast” pace than it might somone working at lower intensity, slowly grinding their way up.

      My understanding (please feel free to correct me) of the added burden of heat is that circulation is increased to move the blood around faster, so it can cool quicker/more. This makes your heart rate go up even if you’r just sat still (i.e. in a Sauna). I’d be interested to know how the addition of strenous exercise affects heart rates, presumably the effect is compounded (if mitigated by acclimatisation) – but I guess its not exponential (even if it feels it!).

      • I don’t think heat (or cold) affects your breathing thresholds, in terms of hbpm.
        So, if you’d ride or climb at the same speed as usually, in normal temperature conditions, you’d get the double effect of the cycling effort and the extra of your body dealing with heat. This could result in a cyclist being unable to cope with his usual pace.

        Also, something hasn’t been mentioned in the article here above : hotter air is less dense, so it offers less resistance (which affects performances, especially on track), but on the other hand, it means that for a same volume of inhaled air, less oxygen is brought into the body, which results in reduced aerobic performances (it’s also true for sportscar, by the way).

  2. The mental effects of heat are also important. I raced the cycle messenger world champs in chicago this summer and the heat index on the course was over 110F. My body was not conditioned to the heat but preparation helped it take the ride in stride. My brain on the other hand got seriously muddled by the heat making thinking about routing very challenging.

    I imagine staying focused and following moves must sometimes be as challenging as pedaling in such heat.

  3. In Arkansas this year, we had something like 22 days in a row of 37-40°C (100-105°F) official temperatures, and on the road, the temperature was often more like 43-48°C (110-118°F). It was a constant struggle to balance going fast enough for the cooling breeze while keeping my heart rate low enough to keep my internally generated heat down. Fortunately my commute is only 32Km (20mi). I can’t imagine the stress during a 160km (100mi) race!

  4. Fantastic photo selection. Shows mutual respect above rivarly. In last Classica San Sebastian there was a breakway at one point where only Henao had a bottle and he was sharing it with four other riders.

  5. Heat is one thing, humidity is another. For me, it’s not too hot to ride (notice I did not write RACE) as long as when you descend you feel some cooling effect. If it’s so hot and humid that the “hair-dryer effect” (as I call it) makes you feel just as hot as you did on the climb, it’s time to call it a day. I’ve been known to hand out popsicles (ice blocks to you Aussies) to our clients on days like this. Luckily for us days like these are not too common as once the heat of July sets in we’re off to the high mountains where even if it is hot, the lack of humidity makes evaporation of perspiration effective. The boys in the Vuelta are really earning their money RACING in conditions like these!

  6. //inrng: how does a bottle of water (or refreshment) get from tap to rider? Does someone fill them or does a manufacturer fill them and deliver to the team the night before?

  7. I think the bedouin drink tea etc because supposedly you absorb fluids at body temperature quicker than you would an (ice-)cold drink. (ignoring any potential longer term dehydrating effects of tea). So although an ice-cold drink might seem like the most inviting thing on a hot day, it may not be the best..

    • Also, where would the Bedouin get ice in the desert to make cold drinks? Here in Phoenix, AZ, the water from the cold tap in the summer comes out around 90-95 deg F. I can only imagine that in the Arabian desert bringing water to a boil would be a lot easier than trying to cool it down!

    • The science behind this is that your body has to expend energy in heating up the cold liquids in your stomach before it can absorb it into your system. This heating of the liquid is using calories that could be better applied to the legs, even if a cold drink feels great on your tongue.

      It was also the rationale behind a diet fad in the 80s, where people ‘ate’ ice cubes instead of drinking water as it burned more calories and supposedly helped weight loss.

  8. One of the reasons for drinking warmer drinks during sport is a matter of digestion.

    If we take a cold drink then blood has to be diverted from muscles to the stomach to warm that drink to our core temperature otherwise we struggle with the coldness of it.

    so a room temp drink can be ingested and digested far quicker than a super-chiled one – it may not have the punch and immediacy of an ice-cold coke, but in terms of digestion its far better for us.

    • Great fact. Cold water for the head, room temperature water for the belly. Until someone tells me that cold water on the head is sub optimal too.

  9. In hotter climates it is a case of drinking hot or at least warm drinks because it sterilises the water , there is a lack of cold water anyway and as others have mentioned, it is easier to absorb and prevents stomach cramps.

    Never underestimate the power of a good brew – the British Army runs on tea.

    • It could, but I guess it isn’t. In fact, since the Vuelta moved from April to August-September, it has been more present in southern Spain than it was before. The basic reason is that the northern half is where you find real cycling passion & tradition, where the roadside will be packed with fans, and where localities are willing to pay to get the race.

  10. Great article.

    A good supplement would be, “Heat Management, or How To Race When It’s Hot” found here: http://myworldfromabicycle.blogspot.com/2010/05/heat-management-or-how-to-race-when-its.html

    Several primary mechanisms and important techniques are thoroughly addressed such as the incredible conductivity of water (25 times more conductive than atmospheric gases), and why keeping your clothing and skin is far more effective than just simply drinking water for cooling (Water intoxication is caused when sodium levels drop below 135 mmol/L when athletes consume large amounts of water without electrolyte additives).

    And several other valuable points are worth knowing….

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