Do you love riding in the blazing heat?  Me neither.  If races were only held in cool temperatures, avoiding the heat when training would be a simple enough proposition: only ride in the morning.  But cycling doesn’t work that way.  Inevitably it’s going to be hot, and you’re going to race.

In simple terms, if you don’t prepare for a hot race, your performance is going to suffer.  Research points toward performance declines of at least 3-6% in hot conditions [1], [2].

In other words, if all you do is ride in cooler temperatures, don’t ever expect to ride well when it gets hot.

Stealing Watts

So why does heat steal so many watts?  In short, even before core temperature reaches the upper threshold for fatigue [3], the body begins to send messages to your legs to work less in an effort to reduce heat production.  Your body’s anticipatory response to higher ambient temperatures may preserve your life but ends up reducing your power output in the process [4].

Thankfully there’s an effective way around this thermal throttling via the process of heat acclimation (HA).  If you live and ride regularly in hot weather, heat acclimatization will likely come naturally.  For the rest of us avoiding heat, or living in year-round cooler temperatures, there are several strategies we can employ to still train and race better in the heat.

**quick disclaimer – obviously remaining safe is the most important objective no matter what HA strategy you might try.  If you feel dizzy, light-headed, or in any other way “not normal” during a HA session, pull the plug and cool off.

Training can be confusing. In our free eBook, we’ll show you four ways to use your data and insights from science to ride better than ever.

Heat Acclimation

Like other forms of acclimation, HA takes time.  Research points toward the need for 8-14 consecutive days of heat exposure to realize the full benefits of HA [1].

If you don’t have two full weeks to dedicate to HA don’t despair, even 5 days of consecutive exposure can improve your ability to ride in the heat [5].  Can’t piece together back to back days?  Try nailing a total of 10 sessions spread out over a month (every third day) [6].

Now that we’ve got the timing down, what does HA actually look like?  The image below breaks down the different ways you might engage in heat training utilizing a variety of strategies.

Click on the image for a brief overview of some of the most widely researched HA methods.

Which strategy should you choose?  Generally the hotter, more consecutive, and more specific to the bike, the better.  Just remember, your HA doesn’t have to be perfect or “by the book” to be effective.  Mix and match strategies and test them on yourself.

The key to an effective HA strategy is to create a thermal impulse strong enough to elicit adaptations [14].   As our chart above shows, this can happen through a variety of methods.

The main takeaway is that no matter your training limitations, strategically introducing HA will insure you give yourself the best chance to ride well when it matters most in hot conditions.

Pre and Mid-Cooling Strategies

So you’ve nailed down your best HA strategy, what about utilizing cooling strategies before and during a race?  Let’s break down some of the most widely studied strategies you might use to cool yourself during a race.

Click on the image for a brief overview of some of the most widely researched pre and mid-cooling strategies

Cooling Strategies Are Full of Maybes

Are any of the above cooling strategies really worth your time and effort?  Maybe, but a few caveats are in order.

  1. Very little pre or mid-cooling research has been conducted on highly trained athletes.  In a practical sense, the more trained you are, the better you’re able to handle riding in the heat, likely reducing the effectiveness of any pre or mid-cooling strategies [22].  Put another way, if you can use HA to “train-away” the potential benefits of pre or mid-cooling, you’re doing something right!
  2. While there is evidence to suggest that some pre-cooling and mid-cooling techniques might improve your performance, test, test, test, for yourself.  Some strategies like ice ingestion can lead to significant GI discomfort [23].  I.E., just like with your fueling and hydration approach, utilize the guidelines of science to develop a strategy you can experiment with well in advance of your most important races.
  3. Inevitably pre and mid-cooling strategies require greater logistical planning.  Factor in more time/potential stress in your pre-race routine before investing in any “extras”.
  4. Pre and mid-cooling strategies should be secondary to nailing your  fueling and hydration.  Don’t neglect the basics.

Putting It All Together (TL:DR)

If you’re hoping to ride well in hot races, strategically exposing yourself to heat can provide a significant performance boost (or at a minimum help you not completely implode in hot conditions).

  • Shoot for around 10 days of exposure, either consecutively or every 3rd day spread out over a month.
  • Choose the heat acclimation strategy that works best within your training/environmental constraints.
  • Get more mileage from your initial heat acclimation by periodically exposing yourself to heat throughout the remainder of your season, especially in advance of upcoming races in the heat [24], [25].
  • Once you’ve nailed your own heat acclimation strategy, and only if practical, experiment with different pre and mid-cooling strategies. These cooling strategies shouldn’t form the foundation of your heat strategy, but they might give you an additional edge when race temps reach their peak.

Training can be confusing. In our free eBook, we’ll show you four ways to use your data and insights from science to ride better than ever.


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Written by Nate Dunn M.S.

Nate Dunn has spent his entire career in education and coaching. As a former teacher and now founder/head coach at Data Driven Athlete, he is most excited about helping cyclists discover their potential as they experience more great days on the bike.