While many people know we need to drink at least eight glasses of water everyday, many do not realize how much our requirement increases during hot weather. As Hong Kong heads into midsummer season, we are seeing temperature constantly rising up to 30°C　or more. Certain groups in the population, such as children, the elderly, and athletes are particularly vulnerable to dehydration, so it is important to keep plenty of water, milk, juices, ice blocks and other fluids on hand.

Water plays a key role in maintaining out internal body temperature which in turn provides the ideal environment for all of our body systems to work effectively. As little as a 1-2% loss in body weight, which often represents less than a litre of fluid, can cause discomfort, loss of appetite, as well as thirst. A 4-5% loss in body weight as a result of inadequate water intake can result in headaches, nausea, inability to regulate body temperature, and poor concentration.

The amount of fluid required by each person is very individual. As a guide, aim to drink at least eight glasses (two litres) of water as a baseline daily amount. If exercising, drink at least two glasses (500 ml) for every hour of exercise, and of course more in hot conditions.

The above information has been prepared by the Dietetic Services of the Hong Kong Sanatorium & Hospital. If you have any comment or enquiry, please feel free to contact us at 2835-8748 or E-mail to dietitian@hksh.com.