No matter where you live, you will most probably experience heat waves and hot weather conditions in the coming years, if not now already. Extreme heat periods are more and more frequent, and don’t spare any region (it’s 50°C in Canada and Siberia but let’s build a few more pipelines and coal plants, and develop an iPhone 28 yeah! (yes I am a staunch ecologist 😏)). Anyway, as the Paris agreement and its mitigation objectives seem already out of reach, let’s cope with it and start to adapt (yes, I am a bit pessimistic too). If you want to know more in details the consequences of climate change on sports (and if you speaks French), WWF France published a report1 in July 2021 explaining in details the impact of a global warming at +2C° and +4C° on physical activities (for example, global warming could cause the French to lose up to 2 months of sports activity!)
As for me, I experienced two kind of hot weather conditions for running. Most common one, heat wave in France (and everywhere else in Europe), temperatures above 35°C in summer with a low degree of humidity. The second type of hot weather, worst in my point of you, was in Vietnam, a combination of extreme temperatures (starting from May, around 40°C), but coupled with a high degree of humidity (above 60%, even 80%), which makes the temperature feels like 50°C sometimes. To give you an idea, I was putting AC in my room in Hanoi at 30 or 32°C (it was the maximum), and I was still feeling like a nice freshness every time I entered. So how to survive and continue running in that kind of hot climate?
What are the risks associated with exercising in a hot climate?
I guess I am not the only one to be aware of heat potential dangers but reckless (or fool?) enough to still go running. Still, studies and health professionals keep warning sports addicts against these hazards.
Risks of exercising while it’s too hot are many:
- Dehydration: that’s obvious, but the hotter is gets, the more you will sweat during your work-out. Sweating is the natural reaction from the body to cool down and regulates its temperature. Most of the time, we tend to already be dehydrated, especially for those who drink tea, coffee (and alcohol!) or other diuretic drinks on a regular basis. Dehydration can lead to dizziness, cramps, heat exhaustion or even heat stroke. The important point is not to wait to be thirsty for drinking, and not to take at once 2L of water because you realise you forgot to drink enough during the day. The best way to avoid dehydration is to drink small quantities, but regularly. If you’re going for a long run or ride (monger than an hour), take a bottle with you (I know it’s annoying without a camelback, most of the time I don’t do it myself, I have to admit), or consider routes where you can find fountains on the way (to drink and pour fresh water on your face!).
- Heat cramps: often affecting the calves, cramps refer to the involuntary tightening of muscles. Heat cramps result from a loss of minerals due to excessive sweating and dehydration, or an insufficient sodium intake. So the solution is not only to drink water (in advance to prevent them), but also drinks or food that are rich in electrolytes (sodium, calcium, magnesium, potassium…), and massage the muscles to relax them.
- Heat exhaustion and heat stroke: feeling weak, dizzy and nauseous after a run under the scorching sun? You’re probably suffering from heat stroke. Heat stroke is a combination of overheating and dehydration. The higher the air temperature, the more efforts your body will have to make to cool down. If the air temperature is higher than your body temp, your body cannot release this excess heat. Add a high humidity factor, and the sweat cannot evaporate, completely, which increases the risk of overheating. In a few words: your body can’t manage to regulate it temperature and gives-up. The situation can get as bad as unconsciousness (or even coma and death in the worst situations), so listen to your body alarms before getting to that point!
- Under performing: well this is not a risk per-se, but rather a consequence of high temperatures. As explained before, when you exercise in hot conditions, your body is already busy regulating its temperature. Basically, there is a kind of competition between the blood that has to go towards the skin to cool down, and the blood that can go to the muscles. As the heat increases, less blood is going to the muscles (less oxygen, in fact), which results in a loss of efficiency.
So how to continue running in a hot climate? I will not develop general tips as you can find already on many blogs, such as run in the shade and don’t wear a cotton shirt. Instead, I will try to provide you with concrete examples from my experiences in the countries I lived in, where I had to confront to two different kind of hot weathers: dry and humid.
Hot and dry: dog days in France
It might not be easy in certain cities, but the best way to cope with heat is to literally run away from tarmac roads. Hot summers are a good excuse to start exploring the parks and nature around, and why not discover trail running.
In Paris, my favourite running spots where green and (relatively) fresh: Buttes Chaumont park, la “coulée verte René Dumont” and the “Bois de Vincennes” (the “Bois de Boulogne” is also a good alternative if you stay at the other side of the city). The later was my favourite one since you’re running on dirt, and it’s big enough for a long run. For the Buttes Chaumont, although you are surrounded by trees, it’s tarmac, and you’re running up and down the whole time, which is not helping if it’s already 30°C). The quays of the Seine are a very popular running zone, but deadly hot in summer.
When I go back to my parents (usually in Summer), I’m lucky enough to have mountains around and plenty of hiking trails.
In any case, I’m paying extra attention to hydration: we don’t only lose water while sweating, but also salt and lots of minerals. If you exercise intensely or more than 1hour or 1.5hour, these micronutrients need to be replaced. Usually, after a long run, I drink one or two glasses with a mixture of fruit juice and water (half-half) with a large pinch of baking soda (or just mineral water works the same). That’s the easiest (and most natural) way to recharge your carbs and minerals reserves. And… I also discovered this summer that non-alcoholic beer is the ideal after-run drink, full of electrolytes and vitamin B! In addition, in hot and dry climates, I try to add a hot drink to my rehydration routine, as it is actually the most effective way to (re)hydrate and cool down. Drinking hot will make you sweat even more and help your body to reduce its temperature effectively2.
Hot and humid : Experience from Vietnam
Definitely the less running-friendly country I have ever lived in (but actually my favourite country to visit so far!) Weather in Hanoi was getting torrid in May, with experienced temperatures above 40-45°C. The same applies to the centre of the country (Hue, Da Nang, Hoi An), even if the climate is dryer. Climate in the South part is hot year-round, with an average of 30°C, the only change is the rainy season from May to November.
The only good news was, that the hotter it got, the lower the pollution level was…
In Hanoi, I was setting my wake-up alarm at 6:30 or so, and went running on an empty stomach at 7am around Hoan Kiem, where you can find some shade. I remember doing that in the rice fields just behind Hoi An, where we stayed a couple of days for a visit, farmers were spreading rice on the road to allow it to dry in the sun. Early morning was already 30°C, and even though I was not alone to run in Hanoi, the farmers of Hoi An were probably wondering what the hell I was doing.
For longer runs in Hanoi, I was running late at night around West lake. Anywhere you go, you won’t find anything else than tarmac and cobblestones in this city. I have never sweated so much, and cooling was very hard. I was heading to the kitchen where my flatmates were using AC or on the rooftop to enjoy the wind, and had to wait at least an hour before showering, otherwise I was starting to sweat again just after.
In terms of hydration, room temp water was my go to, with coconut water and/or water melon.
However, my body adapted like crazy to these sweltering conditions. When I went back to France in July, I was feeling cold under 30°C and never wore a pair of shorts for the whole summer. I was not even sweating, even when I was going for a run during the hottest hours of the day.
In any case, I was not thinking at all about performance, being able to run in such conditions was already an achievement for me. In such temperatures, your muscles are weaker, your heart rate faster. Running is also about staying healthy, and should not entitle extra risks!
And you, what are your tips to run in hot conditions?