Summer is here, and if you’re like many people, you probably can’t wait to have some fun in the sun. But if you’re exercising outdoors, you’ll need to be aware of how the heat, sunlight, and humidity can affect your body. Here’s what you need to know to stay safe during your summer workouts.

When to work out

There’s a reason that many cultures take a siesta around lunchtime. The sun’s rays are most intense between 10 am and 4 pm, which can raise your risk for heat-related illness or sunburn. Whenever possible, schedule your workouts (or any heavy outdoor activity) for early in the morning or late in the afternoon. If you’re sun-sensitive, consider putting off your outdoor exercise until the evening hours.

Safer summer workouts

You may not want to hide in the house all day, but you can choose outdoor activities less likely to cause trouble. Examples include, but are not limited to:

  • Water-based fun. Water will help cool your body, so consider spending time in the pool or ocean. Be sure to wear sunscreen and seek shade whenever you aren’t actually in the water.
  • Gentle workouts. Yoga, stretching, and even a slow bike ride are fine for most people, even during the hottest part of the day. Save the cardio for another time and focus on gently stretching your muscles.
  • Building up. If your summer plans include running a marathon, hiking, or even an outdoor home project such as building a deck, work up to it. Spend several days or weeks gradually adding more activity as your body adjusts.

Fun in the sun can be turned into a full-body exercise with the correct activities. Volleyball strengths the upper body, swimming helps with endurance, and stand-up paddle boarding (SUP) yoga helps with working the obliques and stretch the shoulder.

Signs and symptoms of heat-related illness

Any time you’re active in the heat, there is a chance of overheating. According to the Centers for Disease Control and Prevention (CDC), there are three different heat-related illnesses (other than sunburn or heat rash). Each has its own signs and symptoms and recommendations for what to do if you experience it.

Heat cramps

Heat cramps are the mildest form of heat-related illness. Think of them as an early warning sign for your body. Symptoms include muscle spasms and profuse sweating. If you feel heat cramps coming on, stop what you’re doing and rest in the shade or the air conditioning. Drink some water or, better yet, a sports drink with electrolytes. Wait for the cramps to subside before returning to your activity, and get medical attention for cramps that don’t go away within an hour. It’s also worth checking with your doctor if you have heart issues or are on a low-sodium diet.

Heat exhaustion

Heat exhaustion is more severe than heat cramps, but you may experience them simultaneously during summer workouts. You will likely experience a few, though not necessarily all, of these symptoms:

  • Muscle cramps
  • Heavy sweating
  • Nausea or vomiting
  • Cold and clammy skin
  • A fast but weak pulse
  • Sleepiness
  • Dizziness or fainting
  • Headache

If you experience heat exhaustion, you must act quickly to avoid it progressing. Move to air conditioning if possible, or at least to a shady spot. Loosen your clothes and apply cool, wet compresses to your body. You can also take a cool (but not too cold) bath. Sip water, but do not guzzle it. If your symptoms start to worsen or do not ease within an hour, or if you are vomiting, see a doctor right away.

Heat stroke

Heat stroke is an immediate medical emergency. Symptoms include:

  • Hot, red skin
  • Fever of 103 or above
  • Strong, fast pulse
  • Confusion
  • Dizziness
  • Headache
  • Nausea
  • Passing out

If you see someone experiencing heat stroke, call 911 immediately. Move the person to a cooler spot and use cool compresses to lower body temperature. Do not give fluids.

What to know about sunburn

Sunburn is not considered an immediate medical emergency unless you have blisters on a large part of your body. But the Skin Cancer Foundation notes that just one sunburn with blistering, or five sunburns that are less severe, can double your chances of developing skin cancer. Whether you’re working out or just enjoying the hot weather, always take steps to guard against sunburn. These include:

  • Sun-protective clothing: Wearing fewer clothes might make you feel cooler, but covering your arms and legs can help protect them. Choose high-tech fabrics in a tight weave with an ultraviolet protection factor (UPF) of at least 30. Dark colors are more sun-protective, but you will lose nearly all protection if your clothes get wet.
  • No matter your skin tone or the number of clouds in the sky, always wear sunscreen. Choose a broad-spectrum formulation that guards against both UVA and UVB rays, with an SPF (sun protection factor) of 30 or higher. Don’t forget the tops of your feet and the back of your neck, and reapply every two to three hours.
  • Head, eye, and lip protection: A wide-brimmed, tightly woven hat can help protect your face. You’ll also need lip balm that contains sunblock and wraparound UV-blocking sunglasses.
  • Although you’ll still need sun protection, any shade can help block some of the sun’s direct rays. Work out in a shady grove rather than a concrete parking lot, or at least seek shelter in the shadow of a building whenever you take a break.

Staying hydrated during summer workouts

Hot weather brings an increased risk of dehydration, especially if you’re working out. In general, you should aim for about eight glasses of water per day. But when you’re active in the heat, you will need even more, according to the CDC. Be sure you’re fully hydrated before you start, and then drink at least eight ounces of water every 15 minutes during your workout. You’ll also need to rehydrate after you finish since it can take several hours to fully replenish fluids lost to sweat.

You can choose plain water or sports drinks but avoid energy drinks or caffeine. You can also supplement your hydration with water-rich foods such as watermelon, strawberries, soups, and salads. For a sweet but hydrating treat, try a New Orleans-style sno-ball or another ice-based snack such as a snowcone or Italian ice. Just be sure not to overhydrate, defined as consuming more than 48 ounces of fluids in an hour, as this can lower the salt balance in your blood.

Fun in the sun is a summertime tradition, and there’s no reason you have to hide indoors all day. But summer workouts bring potential health risks such as overheating, dehydration, and sunburn, so you’ll need to take active steps to keep yourself safe and healthy.