Summer Marathon Training: 10 Tips for Running in the Heat

Fall marathons are great. When it’s time to race, the temperatures are cooling off.

There’s only one problem. You need to train through the summer – when heat and humidity can make your life miserable.

As much as you might not always like running in the summer – or the winter – weather, you will be a much better runner if you commit to training year round. You just need to learn to make some adaptations to your training to make it through the summer months and come out the other side in one piece.

After suffering through a few New Jersey summers, here are some things that I’ve learned about how to survive marathon training in hot weather.

Why Is Running So Hard in the Summer?

First, you need to stop and recognize that running in the heat is harder. When people run through their first summer, they inevitably think, “Am I getting slower?” No, you’re dealing with the effects of hot weather.

Hot weather has an adverse effect on your running ability because it inhibits your body’s ability to maintain a normal temperature. One thing that induces fatigue – and will eventually cause your body to shut down – is your rising body temperature. As you run, you generate heat, and your body needs to dissipate that heat. In moderate temps, that’s not so hard. When the mercury rises, it becomes increasingly difficult.

One way your body handles this problem is by pumping more blood to your extremities. This helps cool you off – but it comes at a cost. Your heart rate will rise to a higher level than it otherwise would for a given pace or intensity.

A related problem is humidity. Your body’s most effective way of cooling off is to sweat. The sweat evaporates, cooling your body. When the humidity is high, the sweat won’t evaporate. Instead, you just get wet. And miserable. The worst days for running aren’t the warm days – they’re the warm, humid days.

You can still run in the heat, but it requires you to adapt your pace to be slower and potentially shorten your runs to limit their duration. You can’t rely on your body to regulate its temperature as well, so you have to make accommodations.

Last summer, I spent a week in Florida. The weather there was truly hellish. And it’s a great demonstration of the impact of summer weather on running. Read about it here.

Tips for Running in the Heat and Humidity

Now that we’re agreed that running in the summer is tough, here are ten tips for making it through in one piece.

  1. Take time to get acclimated. It gets easier.
  2. Pay attention to the heat and humidity, and always check the weather forecast.
  3. Be extra attentive to your hydration and nutrition needs.
  4. Schedule your runs to avoid the heat and the sun.
  5. Move inside if you have access to a treadmill.
  6. Slow down your paces accordingly.
  7. Try trail running. It’s cooler and sheltered from the sun.
  8. Shorten your runs and your individual workout intervals.
  9. Dress for the weather, and have no shame.
  10. Prioritize recovery. Rehydrate quickly and make sure you sleep enough.

Keep reading, and I’ll explain each of these running tips in a bit more detail.

Take Time to Get Acclimated to the Heat

Above all else, remember that it does get easier.

Running in the heat is a stressor, but your body will adapt to it in the same way that it eventually adapts to running at elevation. If you’re aware of this, you can set yourself up for success by taking it easy in the beginning of the summer.

When you spend time in a hot environment – and especially when you spend time exercising in it – your body adapts to it. You’ll begin to sweat sooner, and you’ll be more efficient at cooling off. Part of it is likely psychological, as well, as your body relearns the limits of what it can do.

The first day can be a real shock. I hate those first warm spring days, when the weather starts to get humid. I also hate leaving New Jersey in February to run in Florida weather. The weather isn’t actually all that bad, but when you’re used to low temps and low humidity even a moderately warm day can be a shock to the system.

But after a week or two, you’ll start to get used to it. It still has an impact, so you should still take some precautions and make some adjustments to your training. But peak summer training will be easier than the first couple of weeks. Just stay consistent and know that it does get better.

Pay Attention to Heat and Humidity

Regardless of how you deal with the summer heat, the first thing you need to do is make sure you’re always aware of the weather. Some days won’t be so bad, and some days will be horrible. You should be checking the weather every day before you go out to run, and it helps to check the weekly forecast ahead of time to plan out your week.

If you want to summarize everything in one stat, it’s dew point. This is essentially a combination of temperature and relative humidity that tells you how horrible it is to run. Other things to look out for are your overnight lows and whether or not there’s going to be cloud cover.

If the dew point is below 50, you’re golden. But that will rarely happen if you live in a place with a hot, humid summer like the eastern United States.

Dew points in the 50’s are fine, although you may feel a bit sluggish. Once you get acclimated to the heat, these days probably won’t bother you much. Workouts are do-able, but don’t push the pace.

Dew points in the low 60’s start to get uncomfortable. If you slow down a little bit, you should be ok. But there will definitely be a significant impact on your pace.

Dew points in the high 60’s are problematic. At this point, you need to significantly slow down your pace, and you may want to avoid any kind of long workouts.

If the dew point gets into the 70’s, expect to struggle a lot. I wouldn’t even attempt a workout. An easy run is fine, as long as you go at a very easy pace. But if it’s an option, you may want to find a place to run inside.

Pay Attention to Hydration and Nutrition

Because you sweat more on hot days, it’s important that you pay particular attention to your hydration and nutrition throughout the summer.

I love cold weather running. I could go out for 2+ hours in the winter and not take any water with me. Inevitably, spring rolls around and the weather warms up. I don’t usually notice until I come home from a long run dehydrated, and then I realized it’s time to start carrying water.

In the summer, I carry at least a small amount of water with me if I’m out for over an hour. On a long run that’s going to last more than two hours, I typically take a full hydration backpack. I don’t need the full two liters, but it’s better to have too much.

For shorter runs, I like this hydrosleeve. I’m not a fan of holding things when I run, and this straps on to your upper arm. It holds about eight ounces, and that’s plenty for me to sip on if I’m out for 60 to 90 minutes.

For longer runs, I like this hydration backpack. I avoid using it when I don’t need it, because the extra weight is a bit annoying. But on a hot day, when I’m out for two hours or more, it’s necessary. I drop in a few ice cubes to help keep the water chilled, and then I fill it up. Unless it’s particularly hot, I’ll only fill it up half to three quarters of the way to limit the weight.

For my workouts and long runs, I also make a point to bring along some GU gels. This is an important part of marathon training anyway, since you need to be prepared to take gels during the race. But when you’re sweating extra, it’s important to replace some of those electrolytes. You could get powdered Gatorade instead, but I found out my first summer that I’m too lazy to wash out my water carrier after every run. Instead, I just splurge a little on the gels.

Schedule Your Runs to Avoid the Sun and the Heat

A helpful tactic is to wake up a little earlier and get out before the sun comes up.

In the winter, I sometimes find myself killing time in the morning until the sun comes up because it gets warmer and more comfortable. But in the summer, I try to get out as close to dawn as I can.

The air temperature is lowest as the sun is coming up, so if you can get out before or at dawn you’ll be ok. Once the sun does get up, the air temperature will start rising. And if you’re in the sun, it can compound things and make you even hotter.

When I was in Florida, I woke up at 5:30 so that I could be out of the house while it was still dark. Now that I’m back home, I tend to try and get out around 6:00 to 6:15. That way I’m back from my run by 7:30, before things start heating up.

The one downside to early morning runs is that the humidity tends to be highest early in the morning. Humidity is a function of air temperature, and as the temperature decreases the humidity increases. On particularly humid days, the air can feel heavy in the morning. Getting out at dawn when it’s 65 degrees doesn’t help that much if the humidity is 100%.

The other option, if your schedule is more flexible later in the day, is to run late in the evening. If you go out as the sun is coming down, you’ll benefit from lower humidity as well as declining temperatures. It will probably still be warmer in the late evening than it was in the early morning, but running at 8pm can sometimes be better than running at 8am.

Two men running inside during the summer on a treadmill.

Know When to Move Inside to the Treadmill

I’ve had a running streak going for close to 3 years now, and I couldn’t have done it without my treadmill. There are just some days when it’s not wise to run outside, and that’s when it pays to have a treadmill in your basement. If that’s not an option, look into a low cost gym membership like Planet Fitness.

There are a few situations in which I typically find myself running inside.

The first is a warm, humid day when I have a long workout scheduled. If the dew point is in the mid 60’s, it’s not too hot for an easy run. But it will make a long workout grueling. I’ve bailed on more summer workouts than I care to admit. Once I figured out that I could just run them on the treadmill, though, I had much more success. I fire up a movie and then chug away for two hours.

The second situation is when I sleep in. Maybe I had a late night the day before, or maybe I simply slept through my alarm. But if it’s already 8am when I wake up, and the temperatures are rising fast, I’ll usually hit the treadmill instead of brave the sun. It’s great to have this option when I don’t want to force myself out of bed before 6am for one reason or another.

The third situation is when I’m doing an evening double. With my schedule, if I’m doing a double in the evening it’s usually around 5pm. Right after work and before dinner. At that point, the sun is still up and on hot days it’s still too hot to go outside for a run. So I opt for the treadmill instead.

Bottom line: The treadmill is a valuable tool for surviving marathon training in the summer.

Slow Down Your Paces

If you are running outside, it’s important that you adjust your paces according to the weather. The heat puts a strain on your body, raising your heart rate and increasing your effort at a given pace.

If you try to run at your normal pace, you’ll find that a run feels much harder than it needs to. If you’re attempting a workout, you may find that it becomes impossible. This is particularly true of long threshold workouts, where you’re trying to ride the line between what’s sustainable and what’s not.

The hotter it is and the more humid it is, the more you should slow down. If the weather isn’t too bad, that might only be 10 to 20 seconds per mile. If the dew point is in the mid 70’s, you might need to back off a full minute per mile.

Many people get alarmed in the summer when they slow down, thinking that they are losing fitness or that something is wrong. But it’s normal. The quicker you learn to slow down and back off the pace, the better you’ll feel about running in the summer heat.

And if you really need to put in a quality effort, you may be better off moving inside to a treadmill than trying to adjust to the right temperature outside.

A related tactic is to put quality workouts on the back burner for the summer. Focus on piling up some easy mileage and build your base. When the weather breaks and things cool off in the early fall, you can spend a month or two sharpening your speed with some hard workouts.

A woman running on a hot day through a shaded forest trail.

Hit the Trails

If you don’t typically go trail running, summer is a great time to give it a try.

The trails are usually dry and clean. In the fall, they get covered with leaves. In the winter, they can get snowy and icy. And in the spring, they can get muddy. I find summer time to be when conditions are best.

But most importantly, it’s cooler and shadier on a good trail than it is on the road.

The tree canopy keeps you in the shade, which keeps you cooler. It also absorbs the sunlight and prevents it from hitting the ground. Exposed pavement, by contrast, will absorb sunlight and radiate the heat all day long and into the evening.

There should be a noticeable drop off in temperature as soon as you set foot on the trail and get off the road. If you can’t get out of the house before dawn to avoid the sun completely, this can be a good way to deal with things. Early morning, even after the sun comes up, the weather will still be pretty nice in the woods.

I’m lucky there is a great network of trails about a quarter mile from my house. But even if you have to drive a little bit to get there, trail running may make your summer time training more enjoyable.

Shorten Your Runs and Your Reps

When you are running in the heat, cardiac drift gets worse. This is the phenomenon whereby your heart rate tends to creep up, even if you keep running at a steady pace. Among other things, it’s a result of dehydration and heating up – which of course is much more of a problem on a hot day.

One way to combat this is to shorten your runs. If you find yourself dehydrated and drained at the end of an hour long run, try cutting it short at 45 minutes. This doesn’t necessarily mean that you need to lower your mileage, though. It’s a great opportunity to introduce doubles, and add in an extra 30 minute jog in the evening.

It also helps to shorten your individual reps in a workout and incorporate more breaks. If you’re doing a threshold workout, for instance, you may be better off with 5 minute cruise intervals than a 20 minute sustained tempo. The brief breaks will give you a chance to cool off a little bit. Even on long easy runs, it may help to take a short walking break every few miles.

A man running along the water in the summer with no shirt on.

Dress for the Weather: Less Is More

What you wear in the summer can go a long way towards making your run more – or less – comfortable.

You’re going to be sweating a lot, so the first thing you should do is make sure you’re wearing moisture wicking material. Cotton shirts might be ok in the winter. They are a recipe for disaster in the summer. On a crisp fall morning, I often go out in a cotton tank top. Never in the summer. It’ll be soaked through quickly, and it will probably lead to some unfortunate chafing.

It also helps to wear less clothing. Instead of a short sleeved shirt, try a sleeveless tank top. Better yet, ditch the shirt altogether and go topless. The summer is no time to worry about shame. Whether you’re proud of your body or not, just let it all hang out. Your comfort and survival are more important than what other people may or may not think when you run by. It took me a little time to get used to running topless in the summer, but once I did it was so freeing. And on humid days, it feels so much better.

Your choice of socks are also very important. If they get saturated with sweat, you’re going to be very uncomfortable sloshing your way home. It can also do a number on your feet, causing blisters and chafing. Make sure that they are moisture wicking and that they don’t trap sweat in your shoes.

Finally, be mindful of colors. Especially if you are running later in the day when the sun is up, opt for light colors or white clothing. Dark colors, especially black, will absorb more heat from the sunlight. This just compounds the effects of the hot weather. If you’re wearing a shirt, it should be white or bright.

Prioritize Recovery: Rehydrate and Sleep

One last tip is to pay extra special attention to recovery. Running in the heat can be particularly draining. Your heart rate may be more elevated than usual, and you’ll likely end your run more dehydrated than normal – even if you drink throughout.

As soon as you get home, make sure you rehydrate. Take a nice long drink. If you hydrated during your run with water, and you didn’t take any kind of electrolyte supplement, you should also think about replacing some of those. A salty snack is a good idea. My go-to choice is a handful of peanuts. They pack a nice amount of salt, and they’re also high in potassium.

If you feel overheated and dehydrated, it can help to take a lukewarm shower. Turn on the shower and start with a moderate temperature – whatever you feel is tolerable. Once you get in and get adjusted, slowly turn the temperature down a little. It doesn’t need to be freezing cold.

At some point, make sure you find time to sleep. If you woke up before dawn to go running, a quick nap is a good idea. When I woke up at 5:30 in Florida to go out for my run, that post-run nap was always amazing. Granted, I was on vacation, so I had a lot of free time. But even twenty minutes before you get ready for work can be helpful. And if a morning nap isn’t going to work, try to find time somewhere else for a quick 20 minute nap.

The point is to prioritize your recovery. Running in the heat will leave you more tired than usual, and if you don’t recover properly you’ll end up paying for it eventually.

Don’t Worry: There’s a Cool Light at the End of the Tunnel

If you use these tips and make the proper adjustments, you’ll be able to make it through a summer of marathon training. Then comes the best part: fall weather.

As soon as the weather starts to cool off in late August or early September, you’ll feel like a superhero. Your pace will pick up on easy runs, your workouts will be easier, and you’ll be able to kill it when its time for your race.

Do you have any summer marathon training horror stories? Or tips to help others deal with running in the heat? Drop a comment below – I’d love to hear them!

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.