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  • Writer's pictureJackie K

How runners can stay hydrated in the hot and humid summer months

For most of us, it is hot and humid outside. The conditions can be harsh, and we're sweating. A lot.

And we're still running! We're training for fall races, or we're keeping up with our fitness. Some of us are braving the outdoors, and others are taking it inside because it's just too brutal out there.

Staying hydrated in hot weather becomes a big concern! How much should you be drinking? When should you drink? Should you drink water, or a sports beverage, or something else entirely? What if your stomach sloshes? What counts as fluids? How do you know if you're properly hydrated???

So. Many. Questions.

We know we should be hydrated. We know our performance will suffer if we're not well hydrated (right??). So what do we need to know when it comes to getting - and staying - hydrated??

Fluid needs can vary. A LOT.

One tough thing about hydration and sweating is that no two runners are alike. The amount that you sweat during a run (or any workout) is different than the amount that anybody else sweats. For example, you could sweat a lot more than your best friend, even if you're approximately the same age and size. You might lose 3 pounds of sweat per hour, while they only lose 1/2 pound!!

Plus, how much you sweat in one set of conditions might be completely different than how much you sweat in another set of conditions! Indoors vs outdoors, hot weather vs cool weather, humidity vs dry air, easy runs vs intense workouts... it all makes a difference!!

There aren't super clear guidelines about how much to drink. In general, aim for ~2-3 mL of fluid per pound of body weight a few hours before exercise. Give yourself some time to

Show up already well hydrated

Don't only worry about rehydrating after your run. You'll perform so much better - and FEEL so much better - if you show up well hydrated already.

If you're a morning runner and you wake up thirsty, you're already a bit dehydrated. Have a glass of water before you head out the door, then be really diligent about drinking water the rest of the day so that you're well hydrated the next morning!

If you're an afternoon or evening runner, make sure you're drinking water in the morning and throughout the day, then be sure to drink up after your run before you go to bed!!

Take your time to get re-hydrated and stay hydrated (sip fluids all day long!) rather than trying to rehydrate really quickly by drinking a ton of fluids at once.

Drink on the run

Losing more than 2% of your body weight means you're dehydrated; losing more than that and your performance is going to suffer. For a 150-pound runner, that's losing 3 pounds or more on a run -- which can be really easy to do, especially in the heat or if you're out running for a long time!

Knowing your sweat rate can be really helpful to prevent getting dehydrated on the run. If you know how much you're losing per hour, you know how much to try and consume to prevent that dehydration.

It's not just about water

When we sweat, we lose more than just water -- we lose electrolytes, namely sodium, chloride, potassium, calcium. Consuming sodium will help you absorb and retain the fluids that you're drinking, making your rehydration more efficient. So have a salty snack (like pickles or pretzels) during or after your run. Drink something with some carbs/sugar and salt to help your stomach empty faster -- so you rehydrate better and avoid the stomach sloshing that could happen if you drink too much water too fast.

Plus, you can eat foods to help you rehydrate! Fruits and vegetables are full of water and electrolytes. Soup provides fluids and salt. Popsicles are cold and sweet, so they go down easy. Smoothies provide good nutrition AND hydration.

Know your sweat rate

Your sweat rate is going to be different depending on environmental conditions, so it's good to repeat the test several times. Regardless, here's how to know your sweat rate.

  1. Weigh yourself naked before your run - with an empty bladder! (Your clothes will absorb water/sweat, so ditch 'em).

  2. Go out for a 1 hour run

  3. Measure any fluids that you consume during the run.

  4. Weigh yourself naked after your run.

Every pound you lost on your run is the equivalent to 16 oz of sweat. So if you lost 2 pounds, you lost 2x16 oz = 32 oz of fluids! But don't forget to consider what you drank... if you lost 2 pounds and you drank 10 oz of water, then you actually lost 32 oz + 10 oz = 42 oz of sweat!

Aim to replace 150% of your sweat losses to rehydrate. In the above example, that would be 42 oz x 150% = 63 oz of fluids!

Don't just rely on your thirst

If you're thirsty, you need to drink! But you're not always thirsty, and it isn't the best indicator of your hydration status. Plus, some people have diminished thirst sensations. Want to know the easiest, fastest, and cheapest way to know if you're hydrated? Check your pee! You want it to be a light yellow -- not clear, and not dark. It should look like lemonade, not apple juice or water.

If you're fatigued, have a headache, or lethargic, this might also be a sign that you're dehydrated.

Knowing how to hydrate properly - to get hydrated and stay hydrated - can be tough! It takes some work to get to know your body and how it responds to different environmental conditions, how well you tolerate different fluids, how you feel when you're properly hydrated vs dehydrated vs over hydrated... but it is worth it!

But figuring it out will improve help you increase your energy, run easier and faster, improve your endurance, and feel better overall. Schedule your runner's nutrition strategy call with me today so we can figure out YOUR hydration how it'll help you get on the path to reaching your goals.

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