Summer Running Guide: How To Train When The Sun Arrives

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In the northern hemisphere, summer is in full force. This has come as a reminder that summer running is a whole different ball game to running throughout the winter months. 

In 2021 so far, Western North America experienced an extreme heatwave, resulting in some of the hottest temperatures ever recorded in the region. 

Europe has also seen heat weather warnings this summer, with temperatures in Spain rising to 111° F / 44° C. 

However, when it comes to the dedicated runner, stopping running training in the summer months is often not an option.

They must simply learn to coexist with the heat, as halting running training would leave them stir-crazy. 

But don’t worry, summer running is possible, and it can even be enjoyable!

So, to show you how, in this article I will outline;

  • The risks associated with summer running
  • how to mitigate these risks,
  • when to run,
  • what to wear,
  • And what to bring with you.
Summer Running Guide: How To Train When The Sun Arrives

Is running in summer even safe?

Short answer: yes!

You only have to look as far as races such as the Marathon des Sables, which sees runners cross the Sahara desert over 7 days, where temperatures can peak at 120°F / 50°C. 

Or, the 135 mile Badwater ultramarathon, which takes place through Death Valley, North America’s hottest place, in its hottest month, with temperatures reaching an eyewatering 130°F / 54°C.

But are those runners just built differently?


They have just adapted to summer running. The human body is incredibly adaptable and can you can train it to withstand exercise in very high temperatures.

Of course, whether summer running is safe for an individual depends on many factors, their heart health, just how hot it is, the clothing they wear, whether they are hydrated, whether they are hungover…

Luckily, we are able to mitigate many of these factors, factors that I will focus on in this article. 

Summer Running Guide: How To Train When The Sun Arrives

What are the dangers of summer running?

Exercise-related heat exhaustion is an umbrella term for everything that can go wrong in your body when running in the heat. 


Probably the most common danger of summer running. 

Dehydration can lead to exhaustion, dizziness, increased urination, and low blood pressure. 

To summarise, dehydration feels awful. 

Muscle cramps 

Heat cramps can be very alarming and are when the larger muscles in your body cramp and spasm involuntarily. 

They are often associated with dehydration and training hard in extreme heat. 

They aren’t dangerous in and of themselves, but if you experience them, you should 100% stop your run. 

Headache after running

A side effect of the ever-present summer running nemesis-dehydration.

Headaches during or after running in the heat are an indicator that you are not drinking enough fluids either before or during your run. 

Summer Running Guide: How To Train When The Sun Arrives

Summer Running – Our 5 Tips

The good news is that all of these unfortunate side effects can be kept at bay if you are intentional with your summer running and implement the prevention techniques that are outlined below. 

1. Run in the morning (or in the evening)

As a general rule, the hottest time of the day is between 11 AM and 3 PM. Avoiding these hours is a good place to start when it comes to summer running. 

Running in the morning is not only a great way to set the tone for your day- boosting your mood and getting your workout out of the way- but it is also a great way to beat the heat. 

So go ahead and set an early morning alarm, you’ll feel accomplished and a lot cooler!

Summer Running Guide: How To Train When The Sun Arrives

2. Adjust Your Pace

Studies have shown that your Rate of Perceived Exertion (RPE) is higher affected by heat.

In other words, in hot weather, it feels harder to do the same workout than in cooler conditions.

Our Head Coach Thomas:

“Running based on RPE makes a lot of sense in summer, rather than trying to hit a pre-determined pace while the sun is beating down on you.

Your body is using a lot of energy to regulate your body temperature, so it’s natural that your athletic ability will be compromised.

Instead of trying to battling through the heat, accept that you will be slower, and listen to your body – run based on RPE.

If you usually do a 10k in an hour, maybe on a hot day it’s going to take you 65-70 minutes if you run at the same intensity.”

3. Get used to it

This may sound like a form of cruel and unusual punishment, but getting acclimatised to summer running will make it a whole lot easier.

If you’re training throughout spring and into summer, as the temperatures ramp up, your body should be working on naturally acclimatising with not much extra effort on your part.

However, if you happen to move location and are plunged into searing heat, or a heatwave rears its head, your best bet as a runner is to just get used to it. 

Your body is incredibly adaptable but it is good to build up your heat tolerance. Start with shorter runs in the heat and build them up. 

It typically takes 14 days of consistent running for your body to adjust and acclimatise to the heat. 

With regular exposure to running in the heat, your body will adapt to its new normal. You will sweat more, but lose fewer electrolytes as you sweat. This means that your body will be better able to regulate your body temperature as you run.

Summer Running Guide: How To Train When The Sun Arrives

You will also train the mental side of summer running.

It can be a daunting undertaking, but by building up your mileage gradually, you will not only improve your physical capacity, but you will also build your summer running confidence. 

3. Wear suncream 

Never underestimate the power of the sun! Even on a cloudy day, the sun can cause some serious damage. 

Many skin experts recommend wearing SPF all year round. Whether you do or not, it is essential to wear suncream on those hot sunny days, especially on your face. 

With sunburn, prevention is better than cure- you won’t realise how sunburned you are until it’s too late.  

There is nothing worse than strapping on a hydration vest over burned shoulders!

Summer Running Guide: How To Train When The Sun Arrives

4. Stay hydrated

With dehydration being a real risk when it comes to summer running, it is important to bring along some water with you on your runs- especially if you’re out for any longer than an hour. 

Stripping it right back, the hotter it is, the more you sweat. 

Dehydration puts an enormous load on your body and, according to research, it can amplify your rate of perceived exertion (RPE), as well as increase your heart rate. 

So here are some tips to help you stay hydrated:

i. Drink electrolyte drinks

Electrolyte drinks have been shown to help you to retain water, meaning that you are more hydrated. 

Instead of plain water, try bringing along an electrolyte drink in your hydration vest for an extra hydration boost. Just be sure to thoroughly clean it when you get back!

Summer Running Guide: How To Train When The Sun Arrives

ii. Avoid alcohol

Alcohol is a known diuretic. This means that when you drink it, it causes your body to remove water from your body at a much faster rate than other liquids. 

Hopefully, a pre-run alcoholic drink isn’t on the cards, but it is also wise to avoid drinking a lot of alcohol the night before a day of summer running. 

iii. Drink consistently

This not only goes for the fluids which you take on whilst you run, but also more generally. 

Downing a whole load of water before a run won’t do much for you in terms of hydration. Your kidneys will end up flushing most of it out, leading to mid-run bathroom breaks.

More dramatically, chugging lots of water could dilute your blood sodium levels, increasing your risk of hyponatremia (or a water overload) during your run. 

So drink little and often!

Having a water bottle handy throughout the week is a great way to remind yourself to drink enough water. It is good for your general health and it will make summer running a lot less gruelling.

Summer Running Guide: How To Train When The Sun Arrives

5. Wear the right clothes

Having the right running clothes for the weather can make all the difference. 

Here are some summer running essentials:

i. Wear lightweight shorts and a vest 

Nylon is a great summer running material. It is loose fitting and permeable, meaning that you’ll feel the breeze and you won’t get hot and sweaty under your clothes. 

An added bonus- you can often find very cheap nylon running gear at big sports outlets.

2. Avoid cotton

Cotton is the anti-nylon.

Cotton is a great sweat absorber, meaning that it will leave you with heavy wet clothes and sweat patches. Not only is this not the most glamorous running look, but it means that your sweat won’t evaporate and you’ll have a harder time cooling down. 

Summer Running Guide: How To Train When The Sun Arrives

iii. Wear sunglasses

Squinting against the sun’s rays can get pretty uncomfortable. Not only that but sun-related eye damage caused by UV rays is as real a problem as skin damage. 

UV rays are strongest between 8 and 10 a.m. and between 2 and 4 p.m, so if you’re heading out between these times it is even more important to don some sunglasses.

Invest in some proper sunglasses that protect you from both UV-A and UV-B rays. 

And if you’re not a fan of the classic runners wrap-around sunnies look, you can actually just wear normal sunglasses (as long as they don’t slip off your face). 

iv. Wear a hat

Keep your face in the shade with a visor or a cap. Go for a cap if you’re low on the hair department, or a visor if you want to feel the breeze through your locks. 

v. Wear a running vest/hydration pack 

If you’re out for longer than an hour, you’re going to want to bring along some hydration to beat the heat, as well as some snacks for energy. 

A running vest is the easiest way to go about bringing along all your summer running essentials- suncream, water or electrolyte drink, and some sunnies. 

Get out there!

Now you’re all set to hit the road or trails this summer!

If you follow this advice, you’ll no longer be inclined to use the summer heat as an excuse.

A fan of running in extreme climates? Check out these articles…

On running in the sand

On running in altitude

On running in snow and ice

On running in the desert

Photo of author
Maria Andrews is a runner, adventure lover, and UESCA certified Ultramarathon Coach. When she's not running around the woods or plotting adventures, she's spending time with her nearest and dearest, cooking up a storm, or working on Marathon Handbook's sister website, :)

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