When temperatures hit the sweltering mark, the idea of exercising outdoors can be less than appealing. But sometimes we don’t have a choice.
Fortunately, our bodies have mechanisms, such as increasing blood flow to the skin and producing sweat, that help to regulate our temperatures. But these mechanisms also amp up the physiological strain on our bodies, which, during prolonged exercise, can lead to dehydration.
Because dehydration exacerbates this strain even more, it can impair our performance and, if left untreated, even become dangerous. Signs and symptoms of dehydration include the following:
Dizziness, confusion, lightheadedness
Dry lips, mouth, and skin
Physical and mental fatigue
Decreased pace and performance
Darkened urine (one of the first indicators of dehydration)
Increased body temperature, heart rate, and perceived effort
Thankfully, proper hydration in hot weather can help to reduce your risk for dehydration and optimize performance. Here are a few tips to help you stay hydrated in hot weather.
Start hydrating before you sweat
General guidelines call for consuming 6 mL (0.2 oz.) of fluids per kg of body mass every 2–3 hours in the couple days leading up to a training session or competitive event in the heat, as well as 2–3 hours before it begins.
For example, an athlete weighing 150 lbs. would need to consume about 14 oz. of fluids every 2–3 hours. One way to tell if you’re properly hydrated leading up to exercise (and on a day-to-day basis) is to check your urine color. If you’re hydrated, it will be pale yellow.
Stay hydrated during exercise
Drinking to thirst is appropriate for many settings, but not when you could be at risk for dehydration, such as when you’re exercising in hot weather.
So, how much should you drink during exercise?
A good place to start is to calculate your sweat rate. Everyone’s sweat rate is different, but 1–1.5 liters of fluids per hour is common for athletes performing vigorous exercise in hot temperatures. However, sweat rates can be as high as 2.5 liters an hour or more.
To calculate your sweat rate, weigh yourself before and after exercise. Then, determine the percentage of body mass you lost, and factor in the amount of fluids you consumed during exercise. It can be helpful to work with a registered dietitian to get your sweat rate dialed.
If you don’t perform a sweat test, you could use general guidelines as your starting point. These call for consuming around 24–30 oz. of fluids per hour.
Think beyond water
Water is critical for hydration in hot weather, but it may not meet all of your hydration needs. Endurance athletes often use electrolyte powders to replenish sodium, which is the main electrolyte lost during sweat. Baseline guidelines for sodium are to consume 300–600 mg per hour, but you may want to increase your consumption when exercising in the heat.
Carbohydrates also aid in hydration for hot weather, as they can help our bodies retain water and absorb sodium. For exercise lasting longer than one hour, consider consuming 30–90 grams of carbohydrates per hour, depending on the intensity and duration of the exercise. You could consume carbohydrates via food or an electrolyte/carbohydrate sports drink or powder.
Keep hydrating post exercise
Just because you’re no longer sweating doesn’t mean you can stop hydrating! Typically, athletes should consume 20–24 oz. of water or carbohydrate/electrolyte drink per pound of body weight lost during exercise—within an hour of completing exercise.
You could also use your sweat rate to determine the amount of hydration you should drink. Also, check your urine color following exercise to make sure it stays pale yellow, which indicates proper hydration.
Fine-tune your hydration in hot weather strategy
No two athletes are exactly alike. No two training or racing scenarios are, either. Your hydration in hot weather strategy will vary based on your physiological makeup as well as the logistics of your exercise or event.
For instance, if you’re only consuming fluids at aid stations, you may need to consume more at one time than someone who is carrying fluids for the race. Working with a registered dietitian allows you to develop a hydration in hot weather strategy that keeps your performance at peak levels—and, more importantly, minimizes your risk for dehydration.
To dial in your hydration in hot weather strategy, contact us today.