Coach Jeff

Written by Coach Jeff


How to Run a Marathon in the Heat

With the record heat forecasted for this year’s Boston Marathon many runners are rightfully beginning to panic and look for any tips, tricks and strategies they can implement to run well in the face of oppressive conditions.  Luckily, we’ve written on this topic before and I have run in some pretty warm races, so here are some helpful tips for running a marathon in the heat:

Tricks for running a marathon in the heat

Pre cooling

Pre-cooling is a technique used to slightly lower a runner’s core body temperature before they start running, which in turn extends the amount of time they can run hard before hitting that critical temperature threshold. Recent studies have now confirmed that pre-cooling can significantly improve performance in hot and humid conditions. One study reported that pre-cooling can boost performance by 16%.  A second study showed a 2.6 degree average core temperature difference after a 5k race between subjects who pre-cooled with a vest and those that did not. In fact, Both Olympic medalist in the marathon, Deena Kastor and Meb Keflezighi, attribute their medal winning performances in Athens to the pre-cooling strategy.

While elite runners use specialized cooling vests, you can get creative and do some low cost pre-cooling tricks on your own.

  • First, buy a disposable cooler bag from any drugstore to take with you to the starting line of the race. You should be able to find them at CVS or Walmart or you can also use a regular cooler. Basically, you need something that is going to keep ice frozen for a few hours.
  • Freeze a paper cup of Gatorade or buy some freeze pops and put them in your cooler. Eat the freeze pop or Gatorade slushy 10-20 minutes before your the race. This will cool your core from the inside.
  • Grab a few hand towels or small bath towels and get them wet. Place them in the freezer overnight and put them on your neck, head and back 10-15 minutes before the race starts. Warning: it will be shockingly cold at first. If you don’t mind losing the towels, you can run with them until they are no longer cold.

If you want to read more about this topic, you can read our article on pre-cooling for running in hot temperatures here


It goes without saying that you’ll want to make sure you get all the electrolytes you can. Electrolytes will prevent cramping and maintain better fluid balance. You can drink extra sports beverages to get your electrolytes or you can try to pick up some electrolyte tablets or powdered mixes at the expo or running stores.

While I don’t recommend experimenting with something completely new the day of a race, if you have used anything like these electrolyte products before, you shouldn’t have a problem.

We recently wrote an in-depth post on electrolytes for runners. In that article, we outlined some specific brands and products you can try, which I will outline here:

Hammer Fizz: Calories 10 (per serving)
calcium 100mg, magnesium 50mg, sodium 200mg, postassium 100mg

Nuun: Calories 3
calcium 13mg, magnesium 23mg, sodium 360mg, potassium 100mg

Nathan Catalyst: calories 0
calcium 26mg, sodium 135mg, potassium 60mg

Hammer Endurolytes (1 capsule)
calcium 50mg, magnesium 25mg, sodium 40mg, potassium 25mg

SaltStick Electrolyte Cap
calcium 22mg, magnesium 11mg, sodium 215mg, potassium 63mg

Water on you as much as you can

You should be dumping water on you as often as you can. While this isn’t a revolutionary tactic, sometimes it’s good to be reminded.

  • Because Boston is a downhill start and you’ll want to start extra easy, consider carrying a bottle of cold water to keep squirting on yourself every 5 minutes. Like the pre-cooling strategy, the longer you can keep your skin and core cool, the better you’ll be able to run at the end.
  • If you’re not an elite runner or vying for your age-group title, consider having a friend on course hand you a cold bottle of water late in the race. Late in the race, you might miss a station or only be able to get one cup of water. Having a bottle can help you spread out the strategy of pouring water on yourself over a mile or two.

How much to drink

Generally, you want to drink about 10-12 oz of fluid every three miles. While it may make sense to drink more than this, you also have to be wary of how your stomach will react to drinking that much fluid and still trying to run.

  • Try to spread out your fluid intake so you’re taking small amounts 4-5oz every few minutes. These might mean you have to carry a bottle or be adept at carrying a cup, but it’s worth it in the early miles.
  • Drink early in the race and don’t be afraid to slow down through the aid stations. Missing a water stop when it’s 85 degrees is not a smart idea.
  • While it may be too late to implement this strategy if you haven’t practiced it, hyper-hydration is also a trick you can use to stay hydrated. I won’t get into the complicated details here, but we did write up a full breakdown of hyper hydration for runners if you’re interested.

Strategies for running a marathon in the heat

Don’t be afraid to adjust your pace

You’re going to need to adjust your pace to account for the temperatures. Stating out too fast and overheating is not the strategy to run your best race and stay safe.

With the help of legendary running coach Jack Daniels, I’ve created an online temperature calculator for runners that will help you adjust your race times and pace accordingly. You might not like the numbers, but being 10 minutes off your “perfect” goal race by running smart is better than being 45 minutes off and suffering the last 10km.

RunnersConnect Master Extra

Download your FREE Temperature Calculator now in your members-only download section.

It will help estimate how much your times will be impacted by hot weather. Find out exactly how much to adjust your summer workout and race paces.

Not a RunnersConnect Master member? Click here to learn more

Don’t look at your watch

In 2007, I ran in the very hot and infamous Twin Cities Marathon (the same year they closed Chicago because of the heat). The biggest mistake I made in that race was getting frustrated by looking at my watch and not having a backup plan. Every mile I was running slower and slower because of the heat, but I was actually gaining on the entire field (which is a good reference point for your performance when time is out the window). However, because I was so stuck on my watch and my paces, I defeated myself mentally and forgot to just compete and run to the best of my ability.

I know it’s difficult after all the hard work you’ve put in to reach a goal time, but make the most out of this race my running smart, using the above temperature calculator to create a back-up plan, and focus on your effort and being the best runner you can be on the day.

Focus on what you can control

Finally, in the days leading up to the race, just focus on the elements you can control. Yes, the weather is going to be warm, but you can’t change that. What you can have an effect on is how you prepare. Eat right, get mentally prepared, strategize your hydration plan, and implement some of the tips I mentioned above. While the time might not be a PR, you will perform your absolute best and walk away from the race knowing you gave it your all what will be a memorable day.

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One Response on “How to Run a Marathon in the Heat

  1. You can also stay cool with the KewlFit Performance Cooling Vest. The vest maintains a 58°F temperature for 2-3 hours regardless of the outside temperature.

    It is great to pre-cool before an event, wear during a race to keep the core cool or even as a safe cool down.

    More information on the website

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