Stay Hydrated When Racing In The Heat

Summer has arrived in the South-East region, and it’s not playing around. Our tips for racing hard enduros in the heat could help you to stay ahead of your competition!
SEER’s next race is the Battle of Goats on August 1/2, but our recommendations can be applied to any upcoming training and racing in hot environment.

Remember a key goal for any enduro rider, no matter of competing or exercising in the heat:

Drink enough fluids to maintain your body weight.

Start Early – Get Ahead!

Pre-hydrating with beverages, in addition to normal meals and fluid intake, should be started when needed at least several hours before the race to make sure it is properly absorbed.

For the Battle of Goats, hydrate with 500 mL (16 oz) of water or sports drinks the night before, on Friday evening. Continue with another 500 mL upon waking on Saturday morning, and then another 500 mL of cool water or sports drink 20–30 min before the start of the race.
Bring an extra water bottle to the race start, so you avoid emptying your hydration pack before the race has even started!

By failing to prepare, you are preparing to fail.’ Benjamin Franklin

How Much Do You Need To Drink?

Duration is the Key – in this example 3 hours on Saturday, and 5 hours on Sunday.

When exercise lasts more than 1.5 hours, endurance athletes should ingest glucose/electrolyte solutions to maintain blood sugar levels and prevent dehydration.

The current recommendation is 6–12 fluid ounces every 10–15 min throughout the entire exercise/ race.
This equals at least 24 fluid ounces per hour.

Which is actually not a lot for a hot day. Most likely you will need more!

What Should You Drink?

When racing or training in the heat, having beverages containing electrolytes and carbohydrates can provide benefits over water alone.


If you are out there for several hours, and don’t take any electrolytes in, you increase your risk of dehydration or hyponatremia (low sodium levels). Which pretty much means with water only you are flushing your system out.
Lower levels of sodium can affect your race-day performance: You are more prone to headaches, gut issues and overall fatigue.


Carbohydrates during the race provide energy for your muscles and your brain. This is the reason why you will be better off having 30–60 g of carbohydrate per hour. You can either use a drink mix in your hydration pack (which is the easiest on your gut on a hot day), or by eating an energy bar, dried fruits, or energy gels during the race itself.

Check the carbohydrate content of your current drink mix. A gel has generally 20-25g of carbohydrate. Find a combination which adds up to at least 30 grams per hours and still tastes good!

Highly concentrated drink mixes often do not taste too great after a few hours of racing. Once you get a little bit dehydrated, your systems prefers fluids with lower concentrations. They are easier on your already strained gut.

Do You Need Extra Sodium? How About Salt Tablets?

The days around your race are actually the ones when you are allowed to indulge in salty foods! Usually most Americans consume too much sodium in their diet, which has adverse health effects. But avoid a low-sodium diet around endurance races in the heat!

Eating more salt during the days leading up to a longer workout/ race in the heat helps to maintain fluid balance and prevent dehydration.
The current recommendation for sodium is 300–600 mg per hour during a prolonged exercise bout.

Many providers of electrolyte/ sports drinks eg. Gatorade or Nuun are doing the math for you. The sodium content of Gatorade is about 450 milligrams per liter (32 ounces), and 2 Nuun tablets for 32 ounces have 600 mg.

Salt tablets are a quick and easy way to get your sodium in your system. But since it is a highly concentrated form, it might be hard on your gut. Most athletes are better off getting their electrolytes continuously, like within their hydration. Unless you have successfully tried salt tablets before, better stay away from them.

Is Thirst A Good Indicator?

No! Current sports nutrition research says that neither ‘drink as much as possible’ nor ‘drink when thirsty’ are ideal recommendations for athletes.

There are three good explanations for their rejection:
1) We do not want to flush out our system with too much water.
2) Some athletes do not get thirsty while exercising.
3) Thirst is signaled when we are in a state of light dehydration.

Thirst is a signal when your body weight deficit is around 1–2%. Which is the reason why athletes should NOT depend on thirst to prompt them to drink. It would be too late.

How Much Should You Drink After The Race?

Start with 0.5 L (16 oz) and continuously refill over the next hours until you have reached a urine color brighter than dark yellow.

The current guideline is to drink 1.5 times more fluid than you have lost, and you need to make sure there’s plenty of sodium either in or with the fluid to account for the salt loss too. A simple post-workout rehydration strategy is to drink plenty of water and eat some salty pretzels.

Rehydration takes up to 48 hours after intense/ prolonged exercise in the heat.


Remember, just because you do not see yourself as an ultra-distance athlete, your performance can still suffer due to a low hydration level. Per hour, drink a minimum of 24 ounces of fluids with 300 mg of sodium, and add at least 30 grams of carbohydrate to finish strong!

Our recommendation for race day: Avoid overheating – drink up!

Written by Lisi Bratcher

Leave a Reply

%d bloggers like this: