It’s too hot.

That’s the justification many athletes give to avoid running during the summer months, when daytime temperatures can consistently live in the high 80s and above. But when is heat truly a concern and when is it just an excuse?

Running in heat is not only possible, it can actually offer benefits to your training. Heat is a stress to which the body can adapt. Think of other stresses you can impose upon your body while running: increased speed, longer distances, greater inclines, even a weight vest. All of these factors make running more difficult, but they also improve the body’s overall conditioning.

Imposing and adapting to stress makes your body function better in ideal conditions. Heat can function in the same way if applied in a gradual, careful manner.

“Athletes can train themselves to perform in hot weather, it just takes time,” said CFCOA endurance coach Anthony Madonna. “Begin training at short distances and a slow pace, for short periods of time, and then build to longer workouts at increased intensity.”

In the same way weightlifters start light and gradually increase their load, runners can gradually introduce heat as a stress factor and slowly learn to adapt to it. Here are some tips on how to become better at running in heat:

1. Slow and Steady

Don’t run as far as your normally would, or as fast as you’re used to. Start with a short run, maybe only half of what you would typically do in ideal conditions. And keep the intensity low. Focus on a pace that is steady but slower than normal. As you become comfortable with how your body is responding to the stress of heat, you can ramp things up.

“Understand the signals that you receive from your body,” Madonna said. “This will determine distance, intensity, and length of time.”

2. Water Works

Proper hydration is the most important factor to consider when it’s hot. Running in heat will raise the body’s temperature more quickly, which means the body will produce more sweat to cool it down. More sweat means less water in the body.

“Hydration will vary depending on humidity, sun exposure and the amount an athlete sweats,” Madonna said. “In addition to repletion with water, athletes must make sure they are replenishing their electrolyte stores adequately.”

This means not only drinking before your run, but during it. Bring along a water bottle or plan your route where you know there are drinking fountains. Then, have a recovery drink ready for afterward. Also think about drinking something ice cold just before you run to help lower your initial body temperature

3. Dress for Success

Hot weather is the time to bust out that fancy synthetic running shirt you overpaid for. Avoid full cotton, which collects sweat and can become heavy. Mesh and breathable fabrics are key. Think of light materials and light colors that reflect the sun. The less clothes the better. Men, consider going shirtless (heck, ladies too!). Just be sure to wear a hat and lots of sweat-resistant sunscreen.

Introducing heat may not only improve your conditioning, but there’s even evidence that it’s more efficient in fat burning.

Ready to attack that summer weather? Don’t hit the asphalt at high noon just yet; start instead with moderate heat in the mid morning or late afternoon, then work your way up. And consider going with a friend, or joining up with the CFCOA endurance group (Thursdays at 6 p.m. and Sundays at 9 a.m.). It’s a great way to get support and run safely.

Just like any stress factor, heat can be a good training tool when introduced cautiously.

“Conditioning can teach the body to endure any temperatures,” Madonna said. “It just will take time and patience to really understand the needs and signals of the body during an intensely hot training session.”

Really want to geek out? Here’s a (rather complex) sweat calculator to help you determine how much liquid you’ve lost during your run.

And here’s some more information on the science of training in heat.