Plenty of fluids are part of the prescription for most illnesses, but doctors say that dengue patients need at least one litre (5 glasses) more than healthy people, who should have at least two litres (10 glasses) of water a day. This takes the recommended intake for dengue patients to at least 15 glasses of water a day.
Dr Anoop Misra, director of the department of Diabetes and Metabolism, Fortis group of hospitals, says he advises people with suspected dengue to drink 3 litres a day regardless of whether they have fever or not. If the patient is vomiting and unable to retain water, intravenous (IV) fluids are recommended.
“Dengue patients need more water than usual because the disease is characterised by the capillary leakage syndrome, in which the water goes out of the arteries and veins and collects in various cavities. This leads to haemoglobin concentration in the blood, which shows up in the haematocrit test. This test is the most important indicator of the dengue shock syndrome, which leads to a fall in blood pressure, increased stress on the vital organs and finally, multi-organ failure,” says Misra. The hematocrit test is done to measure both the number and size of red blood cells in people suspected of dengue.
Dengue apart, increased water intake is prescribed for most illnesses, more so if they are characterised by fever, diarrhoea, vomiting or dysentery.
A healthy person’s water intake too depends on several factors such as the environmental temperature, level of activity, state of health, body surface area, and even diet. The need for water rises significantly with strenuous or prolonged physical activity and humidity. In such conditions, some people may need twice the amount of water considered adequate for a sedentary person at lower temperatures.
“People are usually advised to drink up to 10 glasses of water because they also get water from milk, coffee, tea, fruits, vegetables and other foods. You should take into account the total fluid intake, not water alone,” says nutritionist Ishi Khosla, director, WholeFoods. Although caffeine is a diuretic and makes the body lose water through increased urination, it does not lead to a deficiency of body water over time because the effect is fleeting.
Few people know that drinking more water helps in weight loss. Every weight-loss programme recommends drinking lots of water since it both fills you up and improves digestion. “There is greater production of toxins and free radicals in the body of those on a diet, which need to be flushed out,” says Khosla. Surprisingly, most people tend to mistake the feeling of thirst for hunger, and tend to eat calorie-loaded food when what their body is actually craving for is water.
Contrary to popular perception, those with complaints of water retention need to drink more water than usual to flush out excess sodium, which causes water retention. Another group that needs to monitor its daily fluid intake closely is the elderly. “Some people, particularly the elderly, may not feel thirsty easily, which puts them at a risk of dehydration,” says Khosla.