Hot weather calls for hydration preparation: drinking enough fluid is key to avoiding sun-induced headaches and energy slumps.
But what exactly should you drink when it's baking hot, how much and when? Does hot tea really cool you down? What’s the least dehydrating alcoholic drink? Is it better to chug a big glug of water or sip little and often? Will electrolytes help you rehydrate quicker and what's the best thing to drink when you're working out in the heat? Here are the best ways to stay hydrated in hot weather, according to experts.
How much water should you drink a day?
The advice from the NHS is to drink at least six to eight glasses of fluid per day, that's roughly 1.5 to 2 litres and includes all fluids, so water, squash, tea and coffee all count. But as we'll discover, not all fluids are equal.
The heat, though, can increase the amount of fluid we lose to sweat. “This really varies between individuals as some people sweat more than others,” says registered nutritionist Jenna Hope. It stands to reason if you sweat more, drink more.
So be intuitive. “Drink to thirst and slightly beyond as this will help you stay hydrated,” she says.
Sip or gulp? How much should you drink in one go?
Sipping water throughout the day is all good, but if you're someone who forgets, or who likes to gulp, say after a workout, nutritionist and personal trainer Zana Morris recommends 400ml as the optimum amount to take in one go for speedy hydration.
Studies have shown that when people consumed larger amount of water, it moved through the stomach to the small intestine (where it's absorbed) faster than smaller amounts, she explains. "The research found that a larger volume of water puts more pressure on your stomach and digestive system, which speeds up gastric emptying," she says. In the study, 600ml worked better than lower amounts, however, Zana recommends 400ml (a large mug) as the sweet spot to avoid overloading your system, "especially if are of a lighter build or have recently eaten a large meal."
How to know if you’re drinking enough? Aim for 'straw coloured' pee
Keep an eye on your pee - it will give useful signs on how hydrated you are. “The colour of your urine is the best way to monitor hydration,” Hope says. “Aim for a light yellow to clear colour, but be aware that some supplements, like those containing B-vitamins, can cause it to become bright yellow. If you are taking these, it might not mean you’re dehydrated.”
Dark urine could suggest you need to drink more water, but completely clear pee could also mean you’re over drinking water (and too quickly),” warns Harley Street nutritionist Clarissa Lenherr. “The colour to aim for is a lemonade colour with a light yellow hue - ideally it should have very little to no odour, if you have a strong smell it could be a sign of dehydration or an infection.”
If you like iced drinks – switch to warm
Will hot, tepid or cold water cool you down faster? All water is good, so the temperature of it is mostly down to personal preference, but according to the experts, although it sounds counterintuitive, warm or room temperature drinks mostly win out.
You may have wondered why tea is the national drink in sweltering India (on top of hot curries) but a warm cup of tea (and spices) in the heat can really cool you down. “When we drink hot drinks, this causes our bodies to sweat more to compensate for the heat change, and when the sweat evaporates, this works to cool us down,” explains Lenherr. “A recent study by The University of Ottawa found that it is best to have hot drinks when it is hot outside."
Not reaching for the ice could have another benefit. Someone who never puts ice in her drinks, even in 40-degree heat, is traditional Chinese medicine, practitioner Katie Brindle. Why? Chinese medicine believes that ice puts an unnecessary burden on the digestive system because your system has to generate heat, the very thing you don’t want, to counteract the cold and restore balance. “Your body will need to generate even more heat to compensate and ensure that the homeostasis is maintained, which will then have to work harder, stressing the body,” she explains. This can lead to a sluggish metabolism and even brain fog.
“In China, warm water – or at least room temperature water is consumed in every home. Its neutral temperature puts the least amount of stress on circulation, ensuring the smooth flow of blood and qi [energy] around the body. This simple way of keeping well hydrated is one of the most beneficial things we can do for our cardiovascular and nervous systems and it is ideal to have to hand when you are exercising.”
If you love ice - take a cold shower or foot bath to cool down or put a filled hot water bottle in the freezer and have it on your lap or in bed.
If you love coffee - swap espresso for decaf
Caffeine is, a mild diuretic (ie it can make you pee more) which can contribute to dehydration if you're sensitive to it. If you really can’t forgo your morning coffee, it could be worth cutting down by a shot, adding more water or opting for decaffeinated.
If you’re menopausal and having hot flushes – drink rose tea
Hot flushes on top of hot weather seem particularly cruel. For her menopausal clients, Brindle recommends swapping out coffee for a cup of rose tea as studies have shown caffeine (and alcohol) can trigger hot flushes. “Rose flower tea has long been used in Chinese culture to regulate the qi and support the spleen and liver, particularly clearing liver heat and releasing toxic emotions. It is especially good in summer as it also nourishes the heart and cools the body, it may also help promote sleep, aid digestion and even help to relieve certain menopausal symptoms.”
How to make rose tea: pop a small handful of dried rosebuds into your teapot and top with just boiled water. Steep for five minutes and enjoy with a little honey.
For added relief, enjoy it alongside a foot bath. “Soaking your feet before bed is a wonderful Chinese self-care (yang sheng) practice at any time of year but is particularly beneficial during the heat of summer,” Brindle continues. “This is because in TCM, heat, if retained by the body, can impact the spleen energy which, in turn, can agitate the heart (and therefore mind), leading to hot, sticky, and uncomfortable disturbed sleep. By soaking the feet, you will be helping to draw this heat out of the body, promoting peaceful sleep by calming and nurturing the five key organs, all of which have channels at the feet. Use tepid or just warm, rather than cold, water in the summer.”
If you love lemon water – switch to cucumber
Hydrating with a glass of water first thing in the morning is a good idea, adding a squeeze of fresh lemon may make it more enjoyable. Anything that makes you drink more water is good. But take care when it comes to lemon. It’s unlikely to help you hydrate or detox, and could harm your teeth if you’re drinking it in large volumes during the heat. “Adding lemon to your water brings little benefit except for improving the taste for some people,” Hope says. “Additionally, lemon water can contribute to causing acid attacks on the teeth and there’s no evidence that lemon water has a ‘detoxifying effect’ - the body naturally detoxes itself.” If you love lemon-infused water, try switching to cooling cucumber, which is kinder to your teeth and more refreshing.
If you’re working out in the gym – hydrate 45 minutes in advance
We all know that a HIIT class in 40-degree heat is never a good idea, but some gentle exercise in the cooler hours of the day, or better still, in an air-conditioned studio is OK. But Morris urges you to hydrate well in advance of exercise. “You will be hotter and partially dehydrated on arrival due to the heat," she says. "Your circulation and metabolism will then increase with the training, and this is before you go back into the outside world and heat of the day. This all results in increased body heat and the possibility of real dehydration,” she says.
Remember that It takes around 45 minutes for your body to rehydrate, “so please consider your fluid intake well before you train.” Ever left a workout with a headache? You may have left it too late to hydrate, “mid-workout is too late!” she adds.
If you love an energy- or pre-workout drink – make your own
High-sugar anything makes you thirsty. If you’re sweating a lot due to exercise in the hot weather, rehydration sachets containing electrolytes to replenish lost sodium (salt) could have a place in your recovery. Or you could simply make your own, a trend currently going viral on TikTok.
How? Add a pinch of salt to water with a splash of lemon, orange or lime juice, Hope suggests. “Milk has also been found to be just as effective at rehydrating you as high-sugar energy drinks due to electrolytes.”