Heat and Hydration
As long stretches of hot summer days become commonplace, it’s perhaps more important than ever to be aware of how to safely train and recover when temperatures climb. There’s no question that body type/mass and genetics can influence an athlete’s performance in the heat; however, our aptitude to conquer the thermometer is by no means set in stone. One of the biggest weapons in our arsenal is hydration.
Let’s be clear. Drinking 8 cups of water per day simply will not cut it for most people, let alone athletes, but good hydration extends beyond just the amount of pure H2O entering your system each day. What matters most is whether or not we are absorbing it.
What is the right amount?
How much fluid you need, and what it should consist of, is based on many individual factors like sweat rate, electrolyte levels, and activity type and duration. Furthermore, training adaptations and variance in heat and humidity significantly change intake requirements too. The good news is that by following some pretty basic guidelines and employing a bit of guess and check, you can likely dial in an approach that works for you.
Keeping under a 2% change in body weight during an exercise session is important, as performance declines and warning signs of heat exhaustion can increase at this point. Depending on the factors mentioned above, individuals may need between 16 and 32 oz per hour while active, and even for one individual, that amount will change based on exercise intensity and climate conditions.
To estimate fluid loss, weigh yourself in the same state before and after after each workout. For each pound lost, replace about 16 ounces of fluid.
To estimate your individual sweat rate, do the same after an hour of intense exercise, factoring in fluid consumed and expelled
Sweat rate = pre exercise body weight − post exercise body weight + fluid intake during exercise − urine produced
- Hydration must be proactive
- Just like overall fueling, fluids should be consumed in anticipation of activity, as well as in response to exercise (you need to rehydrate AND prehydrate)
- Pay especially close attention if you train more than once/day or have back to back longer days on a weekend. Imagine how a long ride or run Sunday is going to feel if you are already at a deficit when you begin your session on Saturday
- It can take up to a day or more to get back to normal after being in a dehydrated state
- Utilize a sports drink or electrolyte supplement
- Water is not enough, especially in the heat, and flooding the body with water alone can lead to low serum sodium levels (hyponatremia)
- Sports drinks and electrolyte tablets are formulated to help us absorb water effectively. Sodium, in particular is crucial for getting water into the cells
- Many other electrolytes play a vital role in muscle and metabolic function
- Test several types of drinks/formulas with training to find what works best for you
- Consider the amount of sugar in your drink. Understand the type of training you are doing and the quantity and type of carbs you need in your system. Some sessions may warrant a higher dose of sugars/carbs while others might be fine for just electrolyte replacement in the form of a tablet. It’s important to realize that sugar is often a friend during intense training and racing. There definitely is a ‘sweet spot’ for how much you should take in.
- Always have more fluid (and fuel) available than you think you need.
- It’s not just about surviving one single workout, it’s all about recovering, adapting, and being ready to continue training and feeling great. Don’t run the risk of bonking or becoming dehydrated.
- Have fluid available for any swim or run over 30min on hot sunny days
- It’s easy to neglect hydration during shorter sessions. Don’t. Purchase and use a hydration belt or handheld bottle, or do loops where you can return to your own aid-station
- Yes, you still sweat and sill need to hydrate when swimming
- Hydrate in frequent, small doses during exercise for optimal absorption
- Nobody likes a ton of liquid sloshing around in the stomach either!
- Keep it cool
- Use some ice and/or insulated bottles if you have them
If you don’t feel like you have your fueling and hydration down to a science, now is the time to begin some trial and error and put your methods to the test. For more information, check out the links below.