Cycling in the Heat: The Practicalities & the Science

Cycling in the heat: The Practicalities & the Science

Summer riding is lovely in theory: dry roads, long evenings, lighter kit and the chance to get out without packing three layers “just in case”.

But when it’s properly hot, riding needs a bit more planning. Bottles empty quicker, food can feel less appealing, and the simple plan of “I’ll just stop at a shop” isn’t always that simple, especially if you’re riding solo.

In a group, someone can stay with the bikes while everyone takes turns going in for drinks, snacks and ice creams. On your own, you either need a shop where you can keep the bike in sight, a reliable refill point, or enough food and drink with you from the start.

Here’s what’s worth thinking about before you roll out. The practicalities

On hot days, you may need to carry more than usual, especially if you’re riding for more than an hour or heading somewhere quiet. Two standard bottles might not be enough, so consider larger 1L bottles if your frame has the clearance, or carry extra fluid in a frame bag, soft bottle, hydration vest or extra bottle cage. It does not need to be aero; it just needs to get you home comfortably. Start the ride well hydrated, sip little and often from the beginning, and check your route for possible refill points such as parks, cafés, train stations, leisure centres, public toilets or water fountains. If you’re riding solo, a lightweight lock can make quick refill stops much less stressful.

For longer rides, hotter days or sweatier riders, think beyond plain water. Electrolytes or a hydration mix can help replace some of the salts lost through sweat, and a simple setup is one bottle of water and one bottle with electrolytes and/or carbs. Heat can also make food less appealing, so start fuelling early with small amounts often: bananas, bars, chews, dates, gels or a carbohydrate drink can all work well. Where possible, ride in the morning or evening, lower the intensity if you’re out in the middle of the day, and don’t forget sunscreen, sunglasses and lightweight breathable kit.

A little heat can help, but only if you respect it!

There is some useful science behind riding in the heat. When you exercise in hot conditions, your body has to send blood both to the working muscles and towards the skin to help dump heat. That extra cooling job is one reason a normal ride can suddenly feel much harder: your heart rate rises, perceived effort goes up, and it becomes harder to hold the same pace.

The good news is that the body can adapt. With repeated, controlled exposure to heat, riders can become better at coping with warm conditions. Typical heat adaptations include an earlier and more effective sweat response, better blood-flow control, a lower heart rate at a given effort, lower core temperature during exercise, and an increase in plasma volume — essentially the fluid part of your blood. More plasma volume can help support both cooling and cardiovascular function.

One well-known study on trained cyclists found that 10 days of heat acclimation improved performance in both hot and cool conditions, with improvements in time-trial performance, VO₂ max and lactate-threshold power. Other research in cyclists has shown that heat acclimation can improve pacing and performance in hot outdoor time trials, although the exact benefit depends on the rider, the protocol and how well the heat exposure is managed.

So, yes, a bit of carefully managed heat exposure can be useful. But the key words are “carefully managed”. This is not a reason to go and smash yourself in the hottest part of the day. Heat is an extra stress on top of the ride itself, so build up gradually, ride easier than usual, drink properly, and give yourself time to recover.

For most everyday riders, the takeaway is simple: riding sensibly in warm weather can help you feel more comfortable when summer events, holidays or longer rides turn hot. But there’s a big difference between adapting to the heat and being flattened by it.

Quick checklist before a hot ride

• More water than usual

• Electrolytes or hydration mix

• Enough snacks, plus an emergency extra

• Sunscreen

• Sunglasses

• Lightweight lock if riding solo

• Refill points checked

• Backup plan if it gets too hot

• Phone charged
  

Hot-weather cycling can be great, but it rewards a bit of planning. Carry more, drink earlier, eat before you feel empty, and pick the cooler parts of the day where you can. References

Lorenzo, S., Halliwill, J. R., Sawka, M. N. and Minson, C. T. (2010). Heat acclimation improves exercise performance. Journal of Applied Physiology, 109(4), 1140–1147. https://doi.org/10.1152/japplphysiol.00495.2010

Racinais, S., Périard, J. D., Karlsen, A. and Nybo, L. (2015). Effect of heat and heat acclimatization on cycling time trial performance and pacing. Medicine & Science in Sports & Exercise, 47(3), 601–606. https://doi.org/10.1249/MSS.0000000000000428

Sawka, M. N., Burke, L. M., Eichner, E. R., Maughan, R. J., Montain, S. J. and Stachenfeld, N. S. (2007). American College of Sports Medicine position stand: Exercise and fluid replacement. Medicine & Science in Sports & Exercise, 39(2), 377–390. https://doi.org/10.1249/mss.0b013e31802ca597

NHS. (2026). Heat exhaustion and heatstroke. Available at: https://www.nhs.uk/conditions/heat-exhaustion-heatstroke/

NHS. (2026). Heatwave: how to cope in hot weather. Available at: https://www.nhs.uk/live-well/seasonal-health/heatwave-how-to-cope-in-hot-weather/