BEAT THE HEAT!
HOT WEATHER RIDING HACKS
Cyclistsdon’t need Greta Thunberg to tell them that the world is getting hotter. The British summer of 2018 was the joint hottest since records began in 1929. In July 2019 Cambridge recorded the UK’s highest ever temperature of 38.7°C. Spring 2020 saw a record 626.2 hours of sunshine (following the wettest February on record). The length of warm spells has more than doubled in recent decades, from 5.3 to 13 days. And climate change is making Britain’s recent heatwaves 30 times more likely.
Ignoring that this might presage the imminent end of the world, most cyclists have been quietly enjoying these strangely un-British, sun-soaked summers. But because UK riders are unaccustomed to such heat, isn’t it time we took hot-weather preparation seriously?
“Hot weather increases physiological strain so exercise feels much harder than it would in a temperate environment,” explains Dr Jessica Mee, a lecturer in sport and exercise science at the University of Worcester. “This definitely reduces our exercise capability so we’re not able to perform as well. And that comes with the potential for getting some form of exertional heat illness.” These range from heat cramps (muscle spasms) and heat syncope (dizziness) to heat exhaustion (nausea, headaches and excessive sweating) and heat stroke, which is when your core temperature passes 40°C, risking brain damage, organ failure and even death.
No sweat
Even in normal conditions athletes generate a huge amount of heat: for every 100 watts of power we produce, we emit 400 watts of heat. Fortunately, your body boasts some clever mechanisms to aid thermoregulation. The most obvious is the release of sweat, which evaporates on your skin to create a cooling effect. This process is aided by the air flow experienced when cycling – which explains why you should always use a fan during indoor training sessions.
“It’s that imbalance between how much heat we’re producing and how much we’re dissipating that will dictate how hot we get,” explains Dr Mee. “In most environments we’re able to sweat effectively, which prevents a dangerous increase in core temperature. But as it gets hotter our ability to dissipate heat becomes inhibited.”
Another issue is that these natural cooling processes also limit performance. Sweating
leads to dehydration, which thickens your blood, so your heart has to work harder to pump blood around your body. More blood is sent to your skin to release heat, so less goes to your muscles to deliver oxygen and nutrients. The result is a lower power output and a higher heart- and breathing-rate. Your brain also suffers a drop in fuel and neurotransmitters (chemical messengers) leading to fatigue and irritation.
These physical effects are deeply problematic. One Australian study found that when cyclists exercise in 32°C heat their power output drops by 6.5 per cent. Research in the Journal of Applied Physiology showed that dehydration increases carbohydrate utilisation by 8 per cent. And a paper in Medicine and Science in Sports and Exercise found that when cyclists were asked to ride to exhaustion in 30.5°C heat their endurance capacity was slashed by a whopping 42 minutes.
Hot topic
The good news is that your regular rides are already helping to prepare you for hot weather by boosting your sweat response, blood plasma volume and cardiac output. “Part of getting fit is getting hot,” explains Dr Mee. But to perform well in hot weather, you do need specific preparation. That’s why pro teams follow hot weather protocols, which include dedicated hot weather conditioning training and more focused pre- or mid-ride strategies.
The most well-known conditioning technique is acclimatisation on a warm weather camp. Training in hot weather for 60 to 90 minutes for four to 10 days has been shown to elicit a lower resting core temperature, greater blood plasma volume and an increased sweat rate. But this is expensive and impractical, which is why many athletes use simulated ‘acclimatisation’ training instead, such as training indoors with the radiator cranked up. Doing five to 14 one-hour acclimatisation sessions has been shown to increase sweat rate, reduce core temperature and improve performance in the heat.
Dr Mee along with Professor Neil Walsh and Dr Michael Zurawlew of Liverpool John Moores University have been researching a fascinating new way to acclimatise. “We found that if you take a hot bath after exercising in cool conditions, building up from 10 to 20 to 40 minutes (in the bath) over the course of six days, you get a profound reduction in resting core temperature of about a third of a degree, which more than bettered exercise heat acclimation,” explains Professor Walsh.
“This translates to lower body temperature during exercise in the heat, lower heart rate and reduced cardiovascular strain. It was amazing how quickly this got traction in elite sport, from England rugby to top international athletes.”
The precise adaptation involved is quite unique. “We see a reduction in the onset of sweating, which helps initiate cooling, but we’re not seeing an increase in whole body sweating rate,” adds Dr Mee. So your body gets more efficient at managing heat without losing any extra sweat, which could lead to further dehydration. This technique works for super-fit and casual athletes alike and the benefits last for two weeks.
Hot-weather camps are still useful for testing your pacing and fuel strategies. “A blended approach is required,” says Professor Walsh. “There are various ways you can get these physiological adaptations, but other things make up a good performance in the heat, including hydration and pacing.”
The benefit of hot-bath acclimatisation, however, is that you can hit your usual intensities when you train. “In a hot climate there’s a slight reduction in the quality of training,” says Dr Mee. “But when you can train in a temperate condition, which is the benefit of this bath technique, you can keep that high-intensity nature of your training. Like the ‘live high, train low’ approach to altitude training (when you sleep at altitude but train lower in the day), this is a ‘train cool, acclimatise hot’ approach.”
These techniques can help you prepare for hot spells, but what about when the summer days arrive? Should riders avoid the heat and ride in the morning or evening instead? “If the main ‘putting in the miles’ sessions can be done in the day, potentially inducing some adaptations, that can only be seen as a positive,” suggests Dr Mee. “But I wouldn’t recommend an athlete compromises their target sessions by doing them in the middle of the day.” So do your lower-intensity acclimatisation rides in the sun but keep your high-intensity work for the cooler hours.
Fuelling in the furnace
Riding in hot weather demands smart hydration. Cyclists can lose up to 1.5 litres of sweat per hour – a fact worth remembering during indoor sessions too. “Drinking when thirsty is fine but on hot rides above two hours aim for 400 to 800ml per hour,” says nutritionist and CyclingPlus columnist Will Girling (willgirling.com). “Remember that water requirements are individualised based on your sweat rate and the heat, humidity and intensity of exercise.”
To work out your sweat rate, go for a pee, weigh yourself, then do a one-hour racepace workout during which you drink one 500ml bottle. Weigh the liquid before you drink. Now weigh yourself post-ride and work out the weight difference – minus the weight of the bottle you drank. The number you are left with is your estimated sweat rate. Aim to replace every one kilogram lost with one litre of fluid.
Most pro riders carry two bottles on the bike – one filled with water or energy drink and the other containing a salt and electrolyte solution. “The primary component of sweat outside of water is sodium, followed by the other electrolytes, such as calcium, potassium, chloride, phosphate, and magnesium,” explains Girling. Salt binds to the water in your body to help you retain fluids so you should always replenish the salt and electrolytes lost through sweat.
Hot weather also upsets your digestion by reducing blood flow to the gastrointestinal tract. “Dehydration can impair our ability to transport nutrients through the intestine lining,” says Girling. “Heat will lower your appetite so opt for liquids (energy drinks) and semi-solids, such as gels.” But for longer
DO YOUR ACCLIMATISATION RIDES IN THE SUN BUT KEEP YOUR HIGH-INTENSITY WORK FOR THE COOLER HOURS
rides it is better to make homemade flapjacks, and rice cakes: they will have a higher moisture content than dry energy bars, making them easier to digest. Bananas, Torq bars and Soreen Malt Loaf Bars are all suitably chewy and palatable alternatives for hot days.
Chill out
On hot days riders will also benefit from some acute, quick-fire, heat-alleviation strategies. Pro riders drink ice slushies and wrap themselves in fridge-cooled towels before and after a ride. Some place stockings filled with ice cubes down the back of their jersey for a refreshing chill. Others soak a thin cap in cold water and wear it under their helmet.
“Acute strategies definitely help and if we can lower the skin temperature it should encourage heat out of the body and into the environment,” explains Dr Mee. “But it’s about practising these methods: if you feel cooler perceptually, but physiologically you’re not getting the temperature drop, you are going to pace quite differently, which may result in some catastrophic pacing. So make sure you understand what’s happening to yourself.”
Kit choice is as crucial on hot days as it is on cold ones. Your helmet should feature plenty of cooling vents and you need highquality eye-wear to filter harmful UV rays. Light-coloured clothing is better at reflecting heat but some dark jerseys feature a textile called Coldblack that helps reflect the sun to prevent heat build-up. “Colour makes less of a difference than you might think, especially while moving,” explains Yanto Barker, founder of Le Col clothing. “Dark colours do absorb more heat but it is hard to tell unless you are stood still in direct sunlight.” Wearing a baselayer might seem like a strange thing to recommend but it can keep you cool. “They wick sweat away and circulate airflow more evenly to avoid sweat pooling,” adds Barker.
When your feet get hot they can swell, so always wear vented shoes. “Loosen shoe straps or dials to allow your feet more room,” advises Barker. Wear mitts to avoid sweat sores on your hands, and lather up with chamois cream to prevent saddle sores.
To stay cool on hot days, riders need to explore the full spectrum of hot weather strategies, from heat acclimatisation to hydration tabs. But knowing how your own body reacts to the heat is the key to the whole process. “The more you practise in these environments, the better,” concludes Dr Mee. “It will mean you can probably act a little bit earlier, and read some of the signs. With this beautiful British weather, riders should absolutely get out there.”