Drinking enough in a tropical climate, without waiting to feel thirsty

Older adults dehydrate faster and notice it later. The thirst signal weakens with age, several common blood pressure medicines increase fluid loss, and in Malaysian heat the sweat disappears into the air before anyone registers that they have lost anything.

Making it easy to drink

• A filled glass or bottle within reach of where you sit, not only in the kitchen
• A drink with every meal and with every medicine — that is already six or seven glasses
• Cold water, or water with lime, if plain warm water is unappealing
• Soup at lunch, which counts and is easier to take
• Water before, during and after any time outdoors

The counter-intuitive part is the evening. Many older adults drink very little after 5pm to avoid waking at night, and then arrive at the morning already short. Drinking most of the day's fluid before the late afternoon, rather than cutting it off entirely, is the better compromise.

What counts, and what does not

Water, tea, soup and milk all count. Sweet drinks, cordials and soft drinks technically count and are best limited for other reasons. Coffee counts as fluid, though the caffeine is worth watching if sleep is already fragile. Alcohol does not help — it increases fluid loss rather than replacing it, and it is a common reason for a bad night and a worse morning.