Even the most chiseled athlete’s body is still mostly water (60 percent, to be exact). Water plays many roles in the human body, including lubricating your joints, delivering oxygen to your muscles, keeping your synapses firing, flushing out waste, and controlling your core body temperature. So if you’re not getting enough water, think about how the effects of dehydration could slow you down.

Staying hydrated is crucial for athletes, particularly those who are balancing work, family, and other obligations along with their training, and neglecting their fluid intake in the process, dietitian and personal trainer Carissa Galloway, RD, says.

What Are the Effects of Dehydration?

“When you’re dehydrated by even two percent, it affects your performance,” Galloway says.

That’s why it’s important to make sure that your fluids are topped off well before you hit the start line.

“When your body isn’t well-hydrated, it’s like when your phone battery is low,” she says. “You go into power saver mode, which is the opposite of what any competitive athlete wants.”

Related: 10 Things You Didn't Know Hydration Could Do for Your Brain and Body

And once you start racing or engaging in any other physical activity, you’ll compound the effects of dehydration by sweating out water and electrolytes, (both of which are key for muscle contraction). That inhibits muscle function — including that of your largest, most vital muscle, your heart — and leads to cramps and early fatigue.

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The Hydrate Belt is a durable ripstop fabric with lightweight mesh material, it holds one water bottle for easy hydration on the go, and includes one zippered pocket for storage.

How Much Fluid Do You Need to Stay Hydrated?

Fluid needs can vary a lot from person to person, but Galloway recommends this trick to find your baseline: Divide your weight (in pounds) in half, and aim for that many ounces per day at a minimum. A 150-pound woman, for example, would want to drink at least 75 ounces daily.

What you need beyond that amount will depend on how strenuous your workout is, when you’re doing it, and whether you’re a naturally salty sweater. (Yes, that's a thing. And if you find white streaks or residue on your body after a training session, it’s probably you.)

“If you do a gentle 30 minutes on the elliptical, you may not need much,” Galloway says. “But if you’re working out for more than 60 minutes or in 80-degree heat, that’s when you need electrolytes from a safety standpoint.”

Related: 4 Natural Drinks to Substitute for Sugar-Filled Electrolyte Beverages

Your best bet, she says, is to know how the effects of dehydration show up in your body: dark-colored or infrequent urination, feeling light-headed or clammy or getting goosebumps (water helps regulate your body temperature, remember).

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Spartan Electrolyte Tablets are designed to hydrate you as your body needs. The sustained release technology will slowly release just the right amount of electrolytes into the body over a period of 4-6 hours.

When Do You Need to Hydrate?

In a word: constantly. You should hydrate before, during, and after strenuous activity, Galloway says.

Again, everyone’s body is different in terms of digestion and what they can handle, and you want to avoid anything sloshing around in your stomach during your workout. Drinking 4-6 ounces about 30 minutes beforehand will help ensure you’re fueled up.

Related: 3 Training Scenarios When Water Is Not Enough

If you’re taking part in an endurance event — or simply tend to lose a lot of fluids quickly — you’ll want to keep drinking an ounce or two every half hour or so to replenish what you’re losing.

And after you’re done, have a recovery beverage, ideally with some protein and carbs to give your muscles back some of what you depleted. While the recovery window for replacing lost nutrients was previously considered 30-60 minutes, newer research shows that it may actually last up to two hours.

What Is the Best Way to Get Adequate Hydration?

Hydrating isn’t just about chugging gallons of water. You also need to replace electrolytes, important nutrients that water alone can’t replace once you sweat them out. These nutrients, including sodium, potassium, and calcium, help muscle contraction and recovery, says Galloway. A sports drink specially formulated to replace these nutrients is a great choice during and after exercise. She recommends BodyArmor Lyte, which has natural electrolytes from coconut water and only three grams of sugar per serving.

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Post-workout, you’ll want some protein, which helps rebuild muscle tissue in addition to replenishing your stores of carbs. Chocolate milk has long been touted for this purpose, but any protein-based drink is decent (though maybe not as tasty).

Plus — as great alternative to plain water — AC+ION Ion Charged Alkaline Water is filtered and purified multiple times to ensure no added sodium. And with a pH of 9.5, you'll replace plenty of electrolytes with this easy drink. 

Related: Can Different Types of Water Boost Your Performance?

As for other edible products that claim to boost hydration, like goos and chews (gels and energy blocks), Galloway points out that you still need to take them with water to transport the nutrients to your body.

If you experience any of the signs of dehydration, it’s important to cut back your effort level until you can replace those fluids. After all, says Galloway, the most important thing isn’t to finish the race, but to finish the race safely.