Heat can be an ally for some athletes and an enemy for others. We can see riders excel when the mercury rises and temperatures soar over 30C (86F), while others surprisingly fade from the peloton.
How can individuals who typically struggle (or have little experience) in the heat adapt their training to cope with hotter race conditions?
In a special guest blog, Spokes coach Aitor Altuna lifts the lid on how to individualise your training in the heat...
The effects of heat during exercise
When cycling in the heat, the human body is simply unable to exercise as hard as in temperate conditions. There are two main factors contributing to that decrease in performance: heat production and heat loss (for more on heat loss, check out this blog on Why do humans sweat so much?).
A big part of the energy you produce when you exercise comes in the form of heat, while you typically lose part of the heat you generate when not exercising via different methods (e.g. radiation, conduction, convection, and evaporation).
But in hot conditions, those heat-loss mechanisms don't work as well and you can't dissipate the heat as effectively, thus increasing your core temperature. This results in your performance dropping, both because of physiological factors (i.e. increased thermoregulatory demands, inflammation in the gut, less neuromuscular activation) and psychological mechanisms (i.e. less willingness to exercise).
A severe increase in temperature can cause serious issues, including heatstroke and death. So, what can you do to ensure you adequately train in the heat, reach your goals, and avoid potentially fatal consequences?
Analyse your circumstances
It's all about your own individual needs. You need to understand where you are at physically, what your history is, and what you can tolerate.
Firstly, identify in which conditions and context you will exercise. Is it a three-day vacation in a hot climate, or is it a race that you want to win?
If you will only be out in the heat for a couple of days and the aim is to do a few workouts so you don't lose fitness, you probably won't need to do anything specific besides riding early in the morning in order to avoid high temperatures.
If you want to perform in the heat, you need to work on it.
Assuming you want to avoid a huge drop-off in your performance while riding in the heat, you'll need to be able to deal well with conditions.
If you have lived in Arizona your whole life and exercised in that environment, you probably won't need further adaptations.
In contrast, if you live in the north of Canada, where temperatures reach 30C (86F) a couple of times a year, your approach should be completely different because you'll need an 'adaptation protocol'.
The adaptation protocol
A factor to consider when planning an adaptation protocol is your actual fitness. With good aerobic fitness, core temperatures are lower in normal conditions and heat can be dissipated more efficiently.
On the other hand, if you're new to the sport, a little unfit following a long winter, or maybe you’re a sprinter who doesn't have a very good aerobic fitness, you’ll need to focus more on the heat training in order to have a greater ability to dissipate heat.
When adapting to heat, core temperature decreases, plasma volume increases and you start sweating earlier, which leads to greater cooling capacity.
In order to choose your protocol, consider two factors: what kind of protocol do you follow and how long do you follow it?
The main stimuli to drive the adaptations are increasing core temperature and forcing a high amount of sweat. Here you may consider what facilities you have. Do you live in a hot environment? Do you own an indoor trainer? Do you have access to a stationary bike?
If you live in a hot environment, try getting as hot as possible - go out in the middle hours of the day, try finding climbs so you go slower and get hotter.
If you don't have that luxury, you can do it in your basement. Hop on the trainer, turn the fan off, and do everything you need to increase the temperature (e.g. turn the heater on, put the trainer in the bathroom with hot water running).
And, if you don't own a trainer, try borrowing one from a friend or exercise in a gym with a stationary bike.
The duration of the workouts should be around 60-90 minutes, without the need to go too hard, but with enough intensity to sweat heavily.
Regarding the duration of the protocol, about two weeks is the sweet spot, but if you’re really fit you could adapt in just one week.
So, four workouts per week in the heat for one week if you’re fit, or two weeks if you’re not so fit, will put you in a good place to tolerate the heat.
Remember to build it up: start with shorter and easier sessions, and finish it with longer and harder ones. Additionally, carry out the protocol as close to the event where you want to perform in the heat as possible.
Cooling in the heat
Once you're in the environment you've used your adaptation protocol for, you'll still need to keep yourself as cool as possible in order to perform at your potential.
If you're not looking for maximum performance, follow these general guidelines: hydrate yourself well and add some electrolytes to improve rehydration. You can calculate your sweat loss and sodium loss, and tailor your drink to suit your specific needs (take an Online Sweat Test to get your own Personalised Hydration Plan).
If you're trying to maximise performance, you should consider further cooling methods. Always try to stay as cool as possible before exercise. In order to do so, you could use an ice vest to cool yourself prior to riding. But don't cool the legs, as this would impair the benefits from the warm up, and don't cool yourself if your event is a short race where sprinting is key (e.g. track racing) because this might affect your sprinting performance.
A useful cooling technique during a race is to put an ice sock underneath your jersey or in the neck area.
If it's a multi-day event, try cooling yourself as early as possible after each stage to improve recovery, and consider avoiding a warm down, as this will delay the cooling and add more heat.
How you should train in the heat
How you train in heat is dependent on your goals, history and circumstances.
If you're likely to experience heat for a only few days and just want to do a couple of workouts, adjusting the time of the ride according to the temperature will help you deal with it.
On the other hand, if you want to perform on a given day in the heat, an adaptation protocol and cooling strategy are needed to get the most out of yourself.
But, if you just want to keep training during the summer months, try building things slowly. Consider what your history is, how you deal with heat, and plan accordingly.
If you don't deal well with heat, but you need to keep training, apply an adaptation protocol, lower your targets for the workouts and build gradually (i.e. start with easy rides in the heat and carry out harder workouts early in the morning).
Heat is an additional stress, and, if you're not adapted, you'll run into problems if you keep training in the same way as you were in cooler conditions.
So, look at your situation, adapt the training to your needs and abilities, and don't forget the basics: listen to your body and hydrate.