Extreme heat events are increasing temperatures throughout the world. Last summer, June smashed record highs with temperatures reaching 111 degrees F.  With such extreme heat, experts advise that hydrating is one of the most important things you can do.

As you’ve likely heard before, the human body is made up of 45% to 75% water, with most of the water stored in our muscle tissue. Water is important because it helps to transport nutrients, rid the body of waste, lubricate joints, cushion vital organs, regulate body temperature, and provide structure to the skin and tissue.

In contrast, dehydration can cause many issues, including decreasing the body’s ability to cool itself and subsequent overheating; a loss of electrolytes; heat exhaustion; fatigue, weakness; dizziness; nausea; muscle cramping; and fainting. Severe dehydration can lead to heat stroke, which can be a life-threatening condition.

Not only is dehydration bad for your health, it can also decrease your athletic performance. According to one study, losing just 2% of your body weight in fluid can result in a 25% drop in your athletic performance.

If you plan to workout in the extreme heat of summer, it is advised that you drink even more fluids than typical, so you can replenish the water lost from all the sweating you will do. Sweating is your body’s extremely effective way of cooling down, and it’s the main reason we can continue to exercise for prolonged periods—even in pretty hot conditions.

However, it is a double-edged sword, as it also can cause the potential loss of too much fluid including electrolytes which would decrease cardiovascular function, and make us slow down or collapse if it goes unchecked for too long.

Help your body sweat and cool down by staying well-hydrated with water; don't wait until you're thirsty to drink fluids. It is recommended that you drink 15-20 ounces of water one to two hours before you start your workout, another 8-10 ounces 15 minutes before you begin, and 8 ounces every 15 minutes for the entire duration of your exercise.

However, Stavros Kavouras, assistant dean of graduate education and professor of nutrition at Arizona State University who studies hydration and its impact it has on health and performance, says rather than relying on a certain number of glasses of water, pay attention to two simple biomarkers: how often you urinate and what color it is. “When optimally hydrated, you should be going to the bathroom every two to three hours and your urine should look similarly colored to lemonade. If it looks more like orange juice that’s an indication that your body is trying to conserve water and you need to hydrate more.”

“Generally speaking, for most people, [drinking] water is totally acceptable” during a heatwave, says Douglas Casa, a professor of kinesiology and the director of Athletic Training Education at the University of Connecticut, who has been studying hydration for more than 20 years. But if you plan to exercise intensely, consider a sports drink instead of water. Sports drinks can replace the sodium, chloride, and potassium you eliminate through sweating.

You can also increase your body’s hydration level by eating water-rich foods throughout the day, says Julie Brown, RD, an American Council on Exercise (ACE)–certified personal trainer and dietitian with Life Time in Chanhassen, Minnesota. Some water-rich foods include: cucumbers, watermelon, watercress, apples, celery, lettuce, peaches, broth, and zucchini.

If you are getting hot just reading this, keep in mind you can have a great workout inside Success Studio, where the air conditioning is cranked and the sun is shaded. But keep in mind that hydrating is equally as important no matter where you run, step, pedal, or HIIT. So break out the bottle and start hydrating! What are your favorite ways to stay hydrated? Leave them in the comments below.