To keep safely striving towards your fitness goals during hotter months it’s paramount to keep few things in mind. Hot and humid conditions force your body to work harder to keep itself cool. As the body pushes more blood to circulate in the skin the oxygen available for the muscles is reduced. This in turn forces the heart to work harder to keep up with the elevated oxygen demands.
What can you do to keep your body working optimally in hot weather?
It’s not uncommon to lose water at a rate of 1 liter per hour when working in hot conditions.(1) But the sweat is not just plain water. The body also loses a lot of nutrients and minerals as a by product while trying to stay cool.
Most of us know that it’s important to replenish the body’s water levels, but what about catching up on the lost minerals and nutrients. Should we add pinches of salt into our water?
Most exercise in itself isn’t usually intense enough to justify adding salt to the water. Especially for recreational trainees who follow a typical high-sodium western diet. The current recommended sodium intake per day is less than 5 grams, or a one teaspoon(2). Most people plough through this limit each day, often without even knowing it.
But things change when exercising and sweating profusely in hot and humid conditions. Especially if the exercise lasts more than an hour or two. Something that is not uncommon with endurance training enthusiasts or those getting into outdoor activities, such as tennis or hiking.
If your training sessions, competitions or matches exceeds an hour a sports drink with sodium and potassium is often justified, maybe even necessary. For the recreational trainee though it might be enough to stick with plain old water.
How much do you need to drink?
Be vigilant to stay on top of your water intake and drink even if you are not thirsty. The specific amount of hydration needed is highly individual. A person’s sweat rate is influenced by multiple factors including body size, fitness level, intensity, windy or still weather, and temperature. The requirements can even vary between the same person training in different conditions(3).
Don’t just focus on your water intake during the training session. Keeping a healthy water drinking habit throughout the day is important for your overall health and helps to perform better during training sessions.
Just avoid drinking too much as it can negatively affect your performance as well.
Keep an eye out for your fatigue levels as this is a strong signal from the body that something is not right. For another indicator of adequate hydration levels aim for a straw coloured urine.
It’s also possible to drink too much water
A potentially life threatening condition called hyponatremia can happen when the body gets too much water compared to the sodium it has lost. Again, this is more of a concern for endurance athletes and less so for the average population. But, hyponatremia is a nevertheless a thing you should be aware of. Especially if your training lasts for extended period of time.
With outdoor training stick to early mornings or evenings
Getting the workout done first thing in the morning, late afternoon or evening before the sunset allows you to skip the hottest part of the day. And as as the sun is not right on top of you at all times you are also more likely to find shade
Don’t leave training for too late though. You might struggle getting to sleep after finishing your training session. Good rule of thumb is to allow at least two hours to wind down before trying to get to sleep.
On humid and hot days consider training indoors
The body has to work even harder in humid conditions. Since the heat doesn’t evaporate off the skin as efficiently the body has to kick into an extra gear to cool down the core temperature. This puts another layer of strain on the heart.
Wear light weight clothes with light colours
If you still decide to train outdoors stick with breathable, lightweight materials and favor lighter colours. Ideally something that doesn’t absorb sweat too much. Keep your hat on and apply sunscreen as needed.
Or you could choose an activity that helps you to keep cool, such as swimming. Remember to take care of to not get sunburned while in the water.
All in all, don’t ignore the strain that your body has to go through to function in hot and humid conditions. Take extra care, even if you are extremely fit.
Women who are pregnant and people with health issues should avoid exercising outdoors altogether during hot weather. Some medications can also affect the body’s cooling capabilities. If you suspect anything it’s important to talk this through with your doctor.
And when in doubt, play it safe. Sick with air conditioned environments on those unbearably hot and humid days.