Cycling in the Heat

There’s an old saying from a Noel Coward song that only “mad dogs and Englishmen go out in the midday sun.” That extends to cyclists too! Many rides take us into the heat of the day. Environmental strain can have a dramatic effect on our cycling.

We need to prepare both our body and kit to deal with conditions of extreme heat and the damaging rays of the sun.

A great summer day’s cycling ride can really put a smile on your face. As you speed along you create a current of cool wind. Still, we need to be aware of the risks of dehydration, sunburn, and temperature control, especially if you run into an unexpected mechanical problem.

Heat Exhaustion & Heat Stroke: Hot Weather Cycling Risks

Heat exhaustion and hyperthermia are the two big risks for summer cyclists. Heat exhaustion results from decreases in blood pressure and volume. Vital fluid and electrolytes are lost from the body through sweat when exposed to heat for extended periods.

Fatigue becomes far more intense, with symptoms including nausea, profuse sweating and headache. Riders may also feel dizzy and confused.

If you become aware of this, it’s best to stop cycling immediately and find a spot in the shaden to cool down and refuel.

Cold towels can be used to lower body temperature. Ditto for a cool bath or shower.

Many of us will push on despite knowing we’re not in a good place. If you push yourself beyond the above symptoms you risk developing heat stroke. Your body stops sweating, and you suddenly feeling very cold despite the heat.

At this point the condition becomes an emergency. It’s vital to sip at cold drinks and stay awake, and you should call an ambulance.

Whilst we cyclists can do very little about the weather forecast, there is a lot we can do to plan ahead for hot weather.

A few smart equipment choices can mean the difference between a refreshing ride and an ordeal.

1) Stay Hydrated: Ensure you have some 750 ml bidons

Photo Credit: cas_ks

Water is vital to our body’s ability to perform at its highest level. A small percentage loss of the water from our body can have a dramatic, detrimental effect on our performance.

A 2% decrease is measurable and impacts your cycling output. Therefore every road cyclist should maintain their fluid levels all year round. Summer in particular is the time where we are most likely to suffer from heat stress.

Racers in the Tour de France will be seen with 500ml bidons, but these are passed out due to their relative ease of transport through the peloton. Riders will stuff them down the backs of jerseys and in pockets to distribute to teammates.

You may want to look like a pro, but 500ml bidons are probably not enough. I recommend you switch to 750ml water bottles, increasing your carrying capacity by 50%.

Ideally you should be drinking plenty of fluids before, during and after rides. Many coaches cite a minimum 500-800 ml of fluid as prep before a hot and humid ride.

2) Stock up on isotonic drinks and electrolyte tablets for hot weather cycling

If you’re looking for an ergogenic effect, swapping from water to sports drinks can improve hot weather performance.

Isotonic sports drinks are at the same osmolarity as our bodily fluids and can therefore be absorbed into the body as fast as or faster than just drinking water.

You want to look for sports drinks containing 4-8 grams of carbohydrate per 100ml for optimal balance between hydration and energy.

These drinks are also a great way to recover if you’re feeling the effects of heat exhaustion; they will replenish electrolytes lost through sweat.

Alternatively, electrolyte tablets dissolve easily in water. They provide your body with minerals vital for muscular contraction and the regulation of your body’s fluid balance, which  helps us to maintain performance in the heat.

They’re also very easy to stash in your wallet, jersey pocket or saddle bag.

3) Don’t forget about your skin

We all love a glorious sunny day on the bike. It’s what drives us through the sleet, snow and cold. However, never forget the importance of protecting our body from the damaging effects of UVA and UVB radiation.

We all know someone who’s rushed out of the house, forgotten to put the sunscreen on and arrived back home a few hours later looking like a lobster.

Many companies now make specific sports sun creams and sunscreens. They’re more resilient to sweating than regular sun creams, which is a bonus for cyclists. Look for water resistant sun creams which won’t wash away with a brief storm.

High levels of UVA and UVB protection are also a must.

Most sports sun products are available in factor 30 or higher. If you’re fair skinned consider factor 50 protection or higher. Neutrogena produces a great-looking factor 70 sun cream which offers outstanding levels of protection for all sports.

4) Not all cycling jerseys are created equal

Few of us actually have specific summer cycling gear and apparel. We have cycling kit for winter and then everything else we use for the rest of the year. Manufacturers are starting to turn their attention to the demands of cycling in summer.

A key characteristic of summer cycling jerseys is the ability to wick away sweat from the body. This will help to keep us feeling cool and comfortable as the mercury rises.

Lightweight mesh panels are ideal, although be aware that the sun’s rays can penetrate the holes so you may need some sunscreen under your jersey.

A good, snug-yet-unrestrictive jersey will help you to feel comfortable riding in the summer months without limiting your movement. Excess fabric is always going to flap around and annoy you so try to keep it form-fitting.

Pockets are also great for your mobile phone, a few gels or bars, and a small travel-sized bottle of sunscreen in case you need to reapply during a long ride.

Here’s an example: the Castelli Climber’s Jersey is a fantastic women’s road jersey for summer which features a tightly knit mesh which will help wick away perspiration. The cut is fairly close but flattering and the styling simple yet classic with a selection of colours to keep boredom away.

5) Protect your eyes on bright summer days

Alberto Contador agrees. Photo Credit: Bob Aubuchon

The sun can have a devastating effect on your eyes too. Your eyes are particularly sensitive to sunlight. That’s why it’s rare to see a pro at the Tour de France who’s not wearing a pair of sunglasses to protect their vision.

Sunglasses block out potentially harmful ultraviolet (UV) radiation. UV can be attributed to the development of eye problems like cataracts and age-related macular degeneration (AMD).

Additionally, the skin around your eyes is particularly sensitive. Sunglasses can help prevent signs of premature aging.

Always look for good quality sunglasses which block out 100% of the sun’s harmful rays.

Bright summer sun can lead to headaches and strain on your eyes. When looking into the sun we squint, which stresses the muscles around our eyes and over time can lead to eyestrain. A daarker tinted pair of sunglasses will mitigate squint-headaches.

6) Look for a well ventilated helmet

Photo Credit: Richard Masoner

Many of us love to look like our idols from the Tour de France and one of the big cycling fashion trends is the ‘aero’ road helmet.

Many look like something we’d have seen in the early days of cycling helmets with a small number of vents on the front.

Those are great if you’re looking to save valuable seconds or watts. However, they will trap heat inside the helmet which could cause real discomfort when road cycling in hot weather conditions.

You’ll see pro riders swap to a better ventilated helmet on warm days or when there’s going to be lots of climbing involved because ventilation is key to remaining cool.

When choosing a helmet consider when you’re going to be riding. If you ride a lot in hot and dry environments airflow will make a huge difference.

7) Pre-cool prior to racing with a cooling vest

We hardcore cyclists pin numbers to our jersey come rain or shine. We relish those warm summer days as a reward for enduring brutal winter races where we lost feeling in our fingers and toes.

It’s rare to hear of events called off due to conditions being too hot, so every advantage we can get on a scorching day is an advantage.

Cooling vests have been around for years at the elite end of competitive sports. You might remember the Athens Olympics, where temperatures were at times pushing above 100° Fahrenheit and athletes needed to develop strategies to deal with it.

In a study by Hunter et al (2006) it was found that the use of cooling vests for one hour prior to competition reduced rises in core body temperature in runners usually seen during hot weather endurance performance.

High core temperature has been shown to have a negative effect on endurance sports performance. So according to this study, a cooling vest could positively impact your event performance.


1) Warming Up With an Ice Vest: Core Body Temperature Before and After Cross-Country Racing, Iain Hunter, J. Ty Hopkins and Douglas J. Casa, Journal of Athletic Training.