How much to drink in this heatwave?

glass of cold water

Do you know how much to drink when it’s hot? A lot more than most of us think, it turns out. A leading surgeon at Southampton General Hospital recommends that in this heatwave people ought to be downing three litres of water a day – yet he’s found hardly anyone drinks that amount. He says we need a ‘radical culture change’ towards drinking water in this country.

In the past three weeks consultant urological surgeon Bhaskar Somani and his team at the General have seen an increase in the number of people admitted for suspected kidney stones… a chief risk factor of which is being badly hydrated. ‘We should take this opportunity to remind people that consumption of three litres of water a day is a small price to pay to help maintain and improve your health,’ says Mr Somani, ‘particularly during heatwave spells such as the one we are in right now.

‘As the country contends with this sustained period of extremely hot weather we need to draw attention to why attitudes towards hydration remain poor and how we can bring about a radical culture change to address it.’ The surgeon spoke out after a survey of kidney stones patients revealed that just 28% sufficiently increased their water intake despite being advised to do so after treatment. The study of 162 patients who received treatment for kidney stones – for which poor hydration is a significant risk factor – at Southampton Hospital found that:

  • 22% of patients said the reason for avoiding water was because they didn’t like the taste
  • 26% blamed their habits
  • 10% said they only drank water when thirsty


How much to drink

According to the NHS Choices website, people should drink six to eight glasses of water a day – about 1.2 litres. But we would advocate double that at The Hub in normal temperatures. To check out how you’re doing right now, it’s easy to see how well hydrated you are with this simple pee test!

Urine hydration chart

1-3 is healthy pee, 4 to 8 you must hydrate…

As well as preventing kidney stones, good hydration can help:

  • avoid low blood pressure
  • prevent falls and risk of falls
  • improve cognitive functions (for example thinking and communication)
  • wound or pressure sore healing and aid healthy skin
  • prevent constipation as drinking enough water and eating fibre rich foods increases stool frequency
  • people with diabetes to replace fluids lost due to frequent urination
  • prevent urinary tract infections

Source: NHS