Hot weather’s adverse physical impact on endurance performance can elevate the difficulty of any workout, race, or ride. Fortunately, you can improve your execution in the heat through heat acclimatization and mitigate its adverse effects with additional preparation. 

How Does Heat Affect Endurance Performance? 

Hot conditions take a heavy toll on endurance performance. When external temperatures are high, your core temperature steadily rises. A rise in core temperatures forces your system to prioritize self-cooling and allocate more blood flow to your thermoregulation process. As the body prioritizes blood flow toward the skin for thermoregulation, fewer resources are allotted to your working muscles and oxygen supply. This distribution can result in a noticeable decline in performance and a decrease in efficiency on the bike. The longer you spend in the heat, the more prominent these physical effects become. 

Riding in the heat tends to be mentally taxing too. It can increase a workout’s rate of perceived exertion, enhance physical discomfort, and boost feelings of fatigue. Managing these mental effects on top of the physiological effects amounts to considerable challenge. Fortunately, it’s not all bad news. You can mitigate heat’s impact on your physical performance with heat training and a few quick tricks. 

How to Prepare for Hot Conditions

Heat training also referred to as heat acclimation, is a reliable way to prepare for hot conditions. Heat acclimation is an adaptation process that occurs when you repeatedly raise your core body temperature. With time your body adapts by increasing blood plasma and grows more accustomed and efficient in the heat.

It takes between ten and fourteen days to acclimate to the heat. Athletes can integrate heat acclimation into their training regimen by gradually exposing themselves to higher external temperatures during workouts. Heat acclimation is tough on the body. It places more stress, and as a result, will increase your fatigue. It’s best to start slowly with easier workouts and lower temperatures while staying properly hydrated.How exactly you choose to do this is up to you, though.

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You can heat train outside in conditions that mimic the temperature of your event or indoors by riding without a fan. If you have access to a sauna, some athletes leverage hot spaces after their ride to extend the benefits of raising their core temperature. Generally, athletes start by integrating heat into their easier endurance workouts before building up towards harder, more intense workouts.

Heat acclimation can actually become a standard part of your training if you live and ride in a hot place. If it isn’t, you’ll definitely want to integrate an acclimation plan into your training in the weeks before an important event or ride. Additionally, you can include heat training in your general training plan by completing your aerobic endurance workouts in the heat. Either way, if you’re planning on completing an important ride in the heat, you will want to acclimate.

For a deep dive into heat acclimation and its impact on performance, check out: Science of Getting Faster: Heat Training and Endurance Performance

Tips for Managing the Heat

With that said, even with the acclimation process, riding in the heat is still challenging. When it comes time to race or ride in the heat, take every slight advantage you can get. You can implement these tips and tricks during hot rides to stay on top of the weather and ensure you have everything you need to be successful.

1. Hydrate Accordingly 

The weather has a significant impact on how much water and electrolytes you need during exercise. Furthermore, staying hydrated on a ride helps ensure your thermoregulation process continues to function at its highest level. When you’re expecting hot weather, make a hydration plan and expect to take in a bit more water and electrolytes than you usually do.

The recommendation for a regular ride is one bottle of hydration per hour. Depending on how much you’re sweating and how hot it is, you could be drinking two bottles every ninety minutes. If you sometimes forget to drink water during rides, set a reminder on your head unit, watch, or phone. An hourly notification prompting you to finish the bottle you’re working on can be a good benchmark for your ride. Don’t forget to add electrolytes to your hydration, either!

2. Bring Frozen Bottles or Ice in Nylon

Sometimes brief relief from the heat can help keep you mentally charged during a long and hot day. For many athletes, a frozen water bottle or nylon full of ice are good go-to’s. Some athletes like to ride with nylon full of ice down the back of their jersey. Depending on how hot it is, this can provide some cooling effects as the ice melts.

If you don’t like the feeling of ice on your back, freezing your water bottles is an alternative way to bring something cool on your ride. Freezing them will keep your water colder for a more extended period, and if you have a frozen bottle in your jersey, it provides a similar relieving effect to the nylon with ice.

3. Pour Water on Yourself

During a race or ride, you can dump a bottle of cold water onto your back, neck, or legs to provide some temporary relief from the temperature and assist your body’s thermoregulation process. If you’re racing, consider having two bottle hand-ups in the feed zone: one with plain water and one with your fuel of choice.

If you do try this during training or a race, be warned: pouring icy water onto yourself can come as a bit of a shock when you’re outside in the heat. Practice during exercise, and remember not to empty it onto your head or into your face—that’s typically a recipe for sweat in the eyes.

Unfortunately, this tip isn’t beneficial when you’re riding in the humidity. There’s not much you can do when it comes to the heavy humidity. Depending on how it feels to pour cold water over yourself, it could provide some temporary relief, though you might find more benefit from the ice.

4. Wear Light Clothing and Bring Sunscreen

Swapping your favorite all-black kit for a white jersey can make a big difference on a hot day. Darker colors capture and hold more heat than lighter colors do. If you’re racing and your team kit is dark, you might be out of luck. Otherwise, opt for the coolest and most well-ventilated kit in your closet. 

In addition to wearing a light kit, be sure to apply sunscreen before your ride. A sunburn can negatively affect your body’s ability to cool itself, accelerate illness onset by the sun, and increase discomfort. If you’re planning on riding for more than a few hours, you may want to bring some extra sunscreen along too. The time it takes to apply sunscreen during a ride will be well worth it.

5. Foster a Positive Mindset

No amount of heat training, ice, or water can withstand a negative internal dialogue. What you tell yourself before, during, and after a hot ride has a powerful effect on your performance and a long-term impact on your relationship with riding in hot conditions. Telling yourself and others that you can’t endure the heat reinforces the belief that you won’t perform on hot days. 

That’s not to discount the challenge. Riding in the heat is mentally challenging and will test your physical limits. It’s all too easy to lock yourself into the mindset that you can’t cope with the heat, though, which is just an unnecessary mental limitation. Resisting a negative mindset around heat while fostering trust in your resilience and preparation will go a long way on a hot day.