Summer running can be a humbling experience. Running and training in heat and humidity can range from slightly uncomfortable to feeling downright impossible.
I’ll never forget my first run after moving back to Myrtle Beach. After spending days unpacking, we found a new friend to help us navigate the local trail that we had hoped to check out. It was early June, and having just finished my very first ultramarathon a few weeks prior (54 miles at Infinitus), I was quite confident in my ability to run an easy 5 miler. It was early evening when we set off on the trail, the sun had begun to set and the temperature was dropping. Despite our pace being well within the “easy” zone…I barely made it a half mile before I thought I was going to die. The heat, the humidity, it was all a stark contrast from the “still 50 degrees at night” temperatures back in Vermont.
And so began the most humbling experience of my life: my first summer running in the extreme heat and humidity of the South East.
Why we Struggle with Summer Running
There are physiological reasons why we feel slow and sluggish while running in the heat and humidity. When the temperature increases, your body has to work harder to keep it’s core temperature cool while running. It begins diverting blood towards the skin (and away from hard working muscles) to try and disperse heat. As you probably already know, our bodies natural cooling response is to sweat. The sweat evaporating off of the surface of your skin takes your body heat with it, expelling it into the atmosphere: an exothermic reaction that has a cooling effect.
Running in Humidity
However, when you add humidity to this equation, cooling your body becomes even more difficult. When it’s humid, the air is already saturated with water, and the sweat on your skin has no place to go.
So it’s no surprise that the hotter it gets, and the more humid it gets, the more difficult running becomes. Numerous studies have shown that ideal running temperatures are between 44-55 degrees Fahrenheit. But, at a dew point (the temperature the air needs to be cooled to in order to achieve a relative humidity of 100%) of 55 °F running performance begin to be negatively affected (approximately 1%). At a dew point of 65 °F , that increases to 3-5%. Even more dramatic, at 75-80 °F, your running performance can be hindered by upwards of 15%.
Not only is your performance hindered at these higher temperatures, but as the chart above demonstrates, running can actually become dangerous.
Can You Adapt to Summer Running?
To an extent, yes, you can absolutely adapt to summer running. There are extreme limits where the body begins to focus all of it’s energy on keep you cool, and trying to run can prove to be downright dangerous – or even deadly. So it’s important, as you run in the heat, that you are aware of the signs of heat stroke
Signs of Heat Stroke Include:
(but are not limited to)
- Dark-colored urine or cessation of urinating
- Muscle or abdominal cramps
- Nausea, vomiting, or diarrhea
- Profuse sweating
- Pale skin
If you experience any of these signs or symptoms while running in the heat, stop immediately, and seek help.
That said, in more moderate heat the body can adapt, and will learn to better dissipate heat, as well as control its core temperature. I can confirm this fact, now with 5 summers of running in the South Carolina heat and humidity under my belt. I’ve acclimated, and you can too. Here’s how to do it:
Summer Running: 10 Ways to Survive the Heat & Humidity
1. Ditch Your Watch, Run by Effort
Or at least, don’t stress about what the watch tells you. As already mentioned, the heat and the humidity WILL slow you down…or at least make your “normal” effort seem much more difficult. Try running by perceived effort instead. If it’s a recovery run, stay in what I call the “conversational” zone – a pace where you can easily carry on a conversation. If you’re scheduled for a more intense effort, then pick up the pace to reflect that effort. But again, don’t stress about what the actual pace on your watch says.
2. Stay Hydrated
This tip may seem obvious when running in the heat, but it’s definitely worth mentioning. Your body cools itself by sweating. The more you sweat, the greater the chances of becoming dehydrated. So, you’ve got to replace the water that your body expels.
But exactly how much water should you drink?
Well, unfortunately the answer isn’t a simple one. The amount of fluid that you should drink during a run depends on how much fluid you have lost, and how quickly fluid empties from your stomach. And this “sweat rate” not only varies from person to person, it can vary from run to run.
You can determine your own sweat rate by weighing yourself before and after an hour of exercise, while keeping track of how many fluid ounces you consumed during that hour. For every pound you lose, that equates to 16 ounces of fluid that you lost.
Personally I find that sipping water in regular intervals, rather than stopping to ingest large quantities at once, helps keep me from feeling excess fluid sloshing in my stomach.
Related post: How to Choose the Right Running Hydration Vest
3. Don’t Forget About Electrolytes / Salts
Balance out that fluid intake. Yes, too much water can indeed be a bad thing. Keep your electrolyte balance in check to avoid dangerous – and potentially deadly – conditions like hyponatremia (decreased concentration of sodium in the blood). Typically, hyponatremia isn’t a concern, but hot weather can cause runners to instinctively ingest copious amounts of water.
According to the American College of Sports Medicine, inclusion of sodium (0.5-0.7 grams of sodium per liter of fluid) in the rehydration solution ingested during exercise lasting longer than one hour is recommended.
4. Dress for the Weather
Now is the time to find that fine balance between keeping cool and protecting your skin. Remember how we talked about humidity making it harder for sweat to evaporate from your skin? Imagine how hard it is when you’re weighed down by a heavy cotton t-shirt or thick shorts.
Lightweight, sweat wicking material is your friend. Further, lighter colors tend to reflect the heat, helping you keep cooler.
A lightweight hat or visor may also provide a little shade and keep your head cool. And lastly, do not forget your sunscreen!
5. Avoid Midday Runs
This may seem obvious, but for the sake of the “oh I didn’t even think about that!’ crowd, it’s still worth mentioning. The middle of the day is going to be the hottest part of the day in most areas. Naturally, it’s best to avoid running in the mid day sun.
Early morning typically tends to be the coolest part of the day. Later in the evening is also an option, after the sun begins to set. But, from experience I can tell you that the pavement tends to hold on to heat, making the early evening hour runs “feel” relatively hot still.
6. Take Walk Breaks
So many runners I’ve talked to/worked with/run with seem to have this fear of walk breaks, this ridiculous notion that walking will make you less of a runner. I scoff now because I was once one of them.
The truth is, taking walk breaks in the summer heat and humidity actually allows your body to work at a lower overall effort. In turn, this may allow you to get in more distance, rather than burning up and burning out trying to run the entire time. Personally, since distance is what I’m typically training for these days, I’d rather get in higher weekly mileage at a slow, sometimes walking pace, rather than low distance at a faster pace. But that’s just me. See again point 1: lower your expectations.
7. Keep your Body Temperature Down
Use whatever means possible to keep your body temperature down. I’ve found from experience it is worth the extra time and effort to back off early and KEEP your temperature down, rather than to overheat and try to bring your temps BACK down again. In order to keep your body cool:
- Run in as little clothing as possible (toss that shame aside, ladies and gents)
- Use ice or cold water in bandanas or buffs on your head or neck
- Take rest breaks in the shade
- Take walk breaks (see above)
- Cool off in a swimming hole, sprinkler, etc!
8. Recover Well
After your run, focus on recovery. Re-hydrate. Eat healthy foods to help replenish your body with nutrients lost, and nutrients that will encourage healing. Realize that running in this heat will leave you feeling much more exhausted and REST accordingly.
9. Change Your Outlook
You already know that running in the summer is harder. And, you also now know that your paces are going to reflect the heat. So, instead of getting frustrated: change your outlook. Know that you are definitely not alone when it comes to struggling through hot, humid runs: this affects all of us.
Personally, I choose to celebrate every mile that I do log during the summer, rather than dwell on the miles I didn’t get to because it was too damn hot. Change your outlook. Simply accept that not every run is going to feel good, and move on.
10. Get Back Out There!
If your goal is to adapt to running in the heat, then you’ve got to keep getting back out there, even when it might feel frustrating. Give yourself time to adapt, by gradually increasing the time you spend running outdoors. Listen to your body, and react accordingly, as overexposure to the heat truly can be detrimental. But also fight the urge to want to quit simply because the heat is uncomfortable.
Trust me when I say: it gets easier.