You’ve waited all winter for the sun to be shining and temperatures to rise. But by mid July, sweltering temperatures may wreak havoc on your outdoor workouts. Heat exhaustion and heat stroke are potentially serious medical conditions that can be fatal.

Heat exhaustion actually has two categories: water depletion and salt depletion. Water depletion symptoms include excessive thirst, weakness, headache and loss of consciousness. Salt depletion signs include nausea and vomiting, frequent muscle cramps and dizziness. However, neither of these conditions are as serious as heat stroke.

Heat exhaustion can progress to heat stroke if proper intervention is not taken. Heat stroke symptoms include all the signs of heat exhaustion but also rapid heartbeat, confusion, fainting and profuse sweating as well. It’s essential to hydrate and cool the body as quickly as possible. If you’re outside, try to find a shady or cool place, or better yet, get indoors to an air-conditioned room. Also drink plenty of fluids, avoid caffeine and alcohol and take a cool shower or bath. If you’re not recovering within 30 minutes of taking these measures, seek medical attention.

Keep in mind that other risk factors besides the heat may lead to these conditions. Age, certain health conditions and even medications may affect your workouts.

If you’re still willing to meet the heat, here are six tips for staying cool while you heat up that calorie burn.

1. Early Late. It’s usually cooler in the early morning and late evening. Temperatures can be 5 to 20 degrees cooler on the average, especially in the Midwest and mountains. If you’re exercising in the dark, be sure to wear reflective clothing to be seen or wear lights if you’re riding a bike.

2. Lighten Up. Dark clothing may be slimming, but wearing dark clothes can raise your body temperature if you’re out in the sun. Wear light-colored clothing to stay cooler and avoid direct sun if possible. Hiking in the woods can be cooler than in the open meadows.

3. Cotton’s Rotten. Although cotton is a great fabric for its softness and strength, wearing cotton on a warm sunny day during your workout may cause blisters. The fabric holds moisture and then stretches as you move, which causes friction to the body. Wearing wicking fibers like anti-microbial wools can keep you cooler and won’t hold the stink. Staying drier will keep you cooler too. Look for DRYFIT, SWIFTWICK and other brands with  moisture-wicking properties. Also keep in mind that it’s not just your feet that sweat.—armpits, thighs and even your underwear can cause heat friction blisters on those areas as well. That’s why it’s best to wear wicking fibers all over your body.

4. Hydra-cise. While you exercise, be sure to hydrate before, during and after—especially in the heat. If you’re exercising for more than 90 minutes in the heat, you’ll want to replace electrolytes as well with formulated products like Gatorade. Coconut water also can help replace many needed electrolytes, but it is missing sodium, which is a key electrolyte that leaves your body when you sweat. Save money and add a pinch of salt to your water and sip every 10 to 15 minutes.

5. Get Wet. It never feels like you’re sweating while you are working out in the pool so choose workouts like swimming, water aerobics classes or running in shallow water. The key is to keep a lower body temperature to avoid heat stroke. But don’t think that because you’re not sweating that you’re not working hard. Unlike your heart rate, sweat is not an indicator of intensity.

6. Top it Off. Wearing a cool vented hat or visor can help reduce the heat’s effects on your outdoor workouts. Choose lightweight fabrics and light colors that reflect the light. Also be sure to keep it tight enough around your head to stay in place, but not so much that it restricts blood flow. Sunglasses are also a great idea, but choose sport-focused styles so that your nose doesn’t pay the price of a wire digging into your face.

Don’t forget that your skin is susceptible to the sun’s harmful heat rays. Wearing sunscreen is essential to exercising in the sun. There are several free apps that can help remind you to reapply protective sunscreen or have suspicious moles evaluated for skin cancer risk.