One challenge during hot weather is ensuring that we drink enough fluids. Writer Rae Ritchie investigates the warning signs of dehydration – and asks the experts what we can do to prevent it.
It’s not just gardens that wilt when a heatwave hits: a massive 89% of people in the UK aren’t drinking enough water to maintain healthy levels of hydration, with 20% of men and 13% of women drinking no water at all.
Drinking water replaces the fluids we lose each day through sweating, breathing and going to the toilet. But how do we know if we’re not drinking enough? Feeling thirsty seems obvious, but craving a swig of water isn’t just your body’s way of telling you you’re on the road to dehydration – it’s a sign you’re already there.
Here are five other red flags and some expert advice on what you can do to stay hydrated, whatever the weather…
1. Dark urine
If you’re taking fewer than 4-5 trips to the toilet during the day and your urine is dark yellow instead of pale or clear, you’re likely not getting enough fluid (note that certain medications and foods can affect the colour).
Solution: Vary your beverages
While it’s recommended that we drink 6-8 glasses of fluid a day, it’s not only water counts towards hydration. The NHS suggests plain tea, fruit tea and low-fat milk as good alternatives, so even your flat white habit counts – within reason.
Dr Stuart Galloway, associate professor of nutrition and metabolism at the University of Stirling, told me, “We’ve recently shown that caffeine in drinks does not impact negatively upon hydration status over several hours, even at doses up to 400mg/L, which is equivalent to about 4 strong coffees. However, water is the drink of choice to avoid excess calories.”
Feeling more tired than usual or suddenly experiencing a mid-afternoon slump? According to UK GPs, dehydration is the cause of 1 in 10 cases of tiredness and fatigue.
Solution: Choose hydrating foods
Between 20-30% of our fluid intake comes from food, and it’s the healthiest choices that have the highest water content. Dr Sarah Hillier, a registered nutritionist and lecturer in nutrition at Oxford Brookes University, recommends eating plenty of fresh seasonal fruits and vegetables. “Things like melon, nectarines, pineapple, watermelon, strawberries and plums would make a great fruit salad for keeping hydrated. Likewise, big salads with lots of water-based veggies like lettuce, cucumber, tomatoes, pak choi, radishes, courgettes, watercress, peppers and asparagus.”
3. Muscle cramps
Dehydration is always a risk when you exercise, and this risk increases during the warmer weather as you sweat even more. Getting a cramp in your muscles is a big clue that hydration is a problem.
Solution: Prioritise water when you exercise
Dr Hillier advises taking on additional water when you exercise to replace the excess sweat. A supplementary glass or two of water is enough in most cases. Make it a habit to regularly sip as you exercise.
A small region of the brain called the hypothalamus is responsible for a number of vital functions, including regulating hunger and thirst. Occasionally the two wires get crossed and our brain thinks we need food when we actually need more to drink.
Solution: Start hydrating early
Nutrition consultant Johanna Hignett points out, “When we wake up we are dehydrated as most of us have not had a drink for eight-plus hours overnight. Why not make one healthy change and begin each day with a glass of water?”
5. Mental sluggishness
If you find it difficult to concentrate or struggle with tasks that are usually a breeze, you may need to reach for the water bottle to give yourself a boost. A study found that dehydration impaired cognitive performance when it came to tasks involving attention and motor coordination.
Solution: Get strategic with your water
It’s important to drink regularly throughout the day, but if you know you’ve got to crunch some numbers or pay attention at a big meeting, try to drink a couple of glasses of liquid beforehand.
Want to find out more about how to hydrate and what to eat before a workout? Check out our nutritionist’s guide.