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What to Know About Running In The Sun

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Beat the heat and protect yourself from the hot summer sun with these tips! What to Know About Running In The Sun www.runnerclick.com

Winter is finally over, spring has sprung, and the summer heat is well on its way. For runners, that means a lot more miles logged outside with the early morning sunrise to beat the heat, (hopefully) followed by lazy days lounging at the pool with friends and family, rehydrating and refueling for the next morning’s run with water and fruit. If your runs expose you to the intense heat and humidity that long summer days tend to bring, then you will want to be prepared and make sure you are properly protected and ready to go. Preparedness goes beyond just hydration and a running body that is tough and in excellent physical condition. You also need to think about your skin and hair, your eyes, and come packing for potential heat and hot weather-related emergencies. Read on for everything you need to know about running in the hot summer sun!

Maintaining Proper Hydration While Running in the Sun

Hopefully just because it is warm outside does not mean you are only just now thinking about how to properly hydrate yourself for your workouts and runs. Hydration is an important part of training and racing throughout the year, regardless of the temperature, because cardiovascular exercises raise your body’s internal temperatures and signals it to sweat in order to help cool it down. But your body’s muscles and organs need water to operate and function at their highest levels (especially during a run) and so you have to consistently replace the sweat you lose with water and/or hydrating liquids (like fortified sports drinks).

The real issue that heat and the sun bring to the table when it comes to hydration is that hotter temperatures outside mean your body heats up quicker than other times of the year, which results in you sweating more, earlier on in your run. Your body has to work even harder than it normally would to keep your internal temperature at a safe, low degree. Plus, the summer sun not only brings more heat but more humidity. When humidity rises and there is subsequently more water in the air, your body can’t efficiently evaporate the sweat beads that form on your skin because the air is becoming too saturated. If sweat can’t evaporate off of the skin, then your body thinks it should not sweat as much.

But like we mentioned before, sweating is the body’s natural defense against heat to help cool the body down, so if our bodies can’t sweat as much and cool us down, then we quickly become overheated. (On the flipside, though, if you choose to run in dryer conditions where humidity is low, you might be even worse off if not properly hydrated. Sweat will evaporate MORE quickly in drier air, and if it is hot, your body will keep producing sweat – meaning it will dehydrate faster). What does that mean for you? Think muscle cramps and spasms because of large fluid and electrolyte losses, headaches, and nausea. As a runner who runs consistently, it is a good rule of thumb to aim to consume an ounce of fluid per pound of body weight each day. But when you are running in the summer sun and heat, aim to get in closer to 1.5 ounces of water per pound. It seems like a lot, but your safety and ability to run strong no matter the conditions depend on it!

A person's finger applies sunscreen to their skin

Protecting Your Skin

You have to protect your skin from heat and the sun as well. When it is hotter outside, you will want to wear less clothing and layers, to help keep you cooler. That is understandable, but it does not mean you should leave your skin totally exposed. Sunscreen, sunscreen, sunscreen! You need to make sure you lather up with plenty of sunscreens before you head out on your run (as well as just heading outside for any activity you might be doing). Choose a sunscreen that has at least SPF 30, but SPF 50 is even better.

Make sure to cover all of your exposed skin, including your face, ears, neck, and scalp if you have thin hair. Hotter temperatures and more sweat also lead to more painful chaffing and blisters. Invest in a good anti-chafe cream, gel, or lotion and apply that to ‘trouble spots’ in addition to your sunscreen. The areas that are most prone to chafing include areas that rub against clothing or skin on skin rubbing – the groin area, armpits, chest and nipples, and around the sock line or on toes if blisters are a concern. If you already have chafing or blisters and want to protect them, be sure to cover up the areas with a sweat or moisture resistant bandage.

Proper Eye Protection is a Must

A lot of folks, especially runners, don’t really think about properly protecting their eyes from the sun and sun damage. But the bright glare of early morning sun coming up over the horizon can really hurt your eyes if you do not take the right measures to protect yourself. Start out by investing in a quality pair of running sunglasses. Lots of brands make these and can be found at both eyewear stores and running stores. Look for sunglasses that let it no more than one percent UVB and one percent UVA. And opt for lenses that are big enough to cover your whole eye, so that light can’t squeeze in from the side. You can also get protective contact lenses that will shield your eyes from UV rays. Running hats and visors are another great way to make sure the sun does not reflect into your eyes, especially if your sunglasses do not offer full coverage of your eye.

Photo by Kawika Singson
Other Tips for Running in the Sun

Even though summer is the ideal time to build your base mileage and get yourself into shape for the fall running season, the heat might mean you need to be a little easier on yourself. There will be plenty of time and opportunities to get in your long runs, tempo work, and speed workouts on the track. But if your schedule only allows for you to run during the hottest parts of the day, then run by effort and not necessarily by pace, distance, or time. That can be HARD for a Type-A runner, but your body will tell you when it has reached its maximum output threshold and trying to push it past that could lead to serious injury and illness.

Try to beat the heat too, by running during the darker, cooler hours of the morning. When the sun goes down at night, the air cools off and so the wee morning hours are going to be the coolest temperatures, as these are the hours in which the sun has been down for the longest stretch of time. Watch where you are running, too. The treadmill can suck, but if it really is too hot, it will be worth it to take your run indoors to be safe. Be mindful of what you are running on, as darker colored asphalt and concrete gets hotter and stays hotter longer than trails and grassy areas. Plus, there is often more shade when you are out running in nature. And that’s what you need to know about running in the sun!


  1. Jason Fitzgerald, Everything You Need to Know About Running in the Heat, LifeHacker blog

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