Families caring for someone with a wound usually think hard about food and hardly at all about water. Yet many people recovering at home, especially older ones, drink far less than they need. They do not feel thirsty, the glass is out of reach, or they are worried about getting up to the toilet at night.
Dehydration slows healing, and it also causes problems of its own, from dizziness and falls to constipation and confusion. Below: how much to drink, what counts, how to tell when someone is running dry, and the people for whom more is not better.
Why do fluids matter for healing?
Blood carries oxygen and nutrients to a wound, and blood is mostly water. When the body runs low on fluid, less of that supply reaches the healing tissue. Skin that is dry and dehydrated is also less elastic and breaks down more easily under pressure, which matters for anyone at risk of bedsores.
Wounds can also cost fluid. A wound that drains a lot, a fever, sweating in hot weather, diarrhoea and vomiting all take water out of the body, and it has to be replaced. On top of that, dehydration brings its own problems: constipation, urine infections, headaches, dizziness when standing up, and in older people, sudden confusion. Each of these can set recovery back.
How much is enough?
A practical guide for most adults is about 30 to 35 ml of fluid per kilogram of body weight per day, counting all drinks.
| Body weight | Fluid per day | Glasses of 200 ml |
|---|---|---|
| 45 kg | 1.35 to 1.6 litres | 7 to 8 |
| 50 kg | 1.5 to 1.75 litres | 7 to 9 |
| 60 kg | 1.8 to 2.1 litres | 9 to 10 |
| 70 kg | 2.1 to 2.45 litres | 10 to 12 |
| 80 kg | 2.4 to 2.8 litres | 12 to 14 |
Aim for the higher end in hot, humid weather, during a fever, or when a wound is draining heavily. Food supplies some water too, especially dal, curd, soups, fruit and vegetables, so these figures leave a small margin.
Who needs to drink less, not more?
For some people extra fluid is harmful, and their doctor will set a daily limit. That limit takes priority over any figure above. It usually applies to people with:
- heart failure
- kidney disease, especially anyone on dialysis
- liver disease with fluid building up in the abdomen or legs
- a low sodium level in the blood, which their doctor will have mentioned
If the person has a limit, count everything liquid towards it, including tea, milk, dal, soup and curd. Watch for signs of too much fluid: swollen ankles or legs, breathlessness, especially when lying flat, and weight going up by more than a kilogram or so over a day or two. Report any of these to the doctor promptly.
What counts as a drink?
Most liquids count, and variety makes it easier to drink enough:
- plain water, the simplest choice
- milk, which also brings protein
- buttermilk (chaas), lassi and nimbu pani, which suit Indian summers well
- dal water, thin dal and vegetable soups
- tea and coffee in moderate amounts, since they still add fluid overall
- coconut water, though people with kidney disease should ask first because it is high in potassium
- juicy fruit such as watermelon, orange and sweet lime
Limit sugary drinks and packaged juices, especially for people with diabetes. Alcohol dehydrates and slows healing, so it is best avoided during recovery. For diarrhoea or vomiting, oral rehydration solution (ORS) from the chemist replaces salts as well as water.
How can you tell if someone is not drinking enough?
Urine is the easiest check. Pale straw-coloured urine usually means the person is drinking enough. Dark yellow or amber urine, a strong smell, or passing only small amounts means they need more. Some vitamin tablets turn urine bright yellow, so judge by how dark it is, not by the brightness.
Other signs include:
- a dry mouth, dry or cracked lips
- headache or unusual tiredness
- dizziness or feeling faint on standing
- constipation
- sudden confusion or drowsiness in an older person
The old skin-pinch test is unreliable in older people, whose skin is naturally less elastic, so do not depend on it.
Why do older people drink so little?
The reasons are usually practical, which means they can be worked around:
- Thirst fades with age, so older people often do not feel thirsty even when they are short of water.
- Many worry about needing the toilet at night, or about leaking, and quietly drink less to avoid it.
- A glass across the room may as well be in another house for someone who cannot easily get up.
- Heavy steel tumblers are hard for weak or shaky hands to lift.
- Memory problems mean drinks get forgotten.
- Swallowing difficulties can make thin liquids unpleasant or unsafe.
Each of these has a practical fix. Offer drinks on a schedule instead of waiting for thirst. Give more fluid earlier in the day and a little less after about 6 pm, without cutting the daily total, so night-time toilet trips worry them less. Keep a light cup with a lid, spout or straw within reach at all times. Fill it only halfway so it is easy to lift. Offer a sip every time you enter the room, and link drinks to routines, such as with each medicine and after each trip to the toilet. Keeping a tally of glasses on a sheet of paper by the bed helps the whole family see how the day is going.
If the person coughs or splutters when drinking, tell the doctor and ask about a swallowing assessment. Thickened drinks are sometimes advised, but only after an assessment.
A simple drinking routine for one day
For a 60 kg adult without a fluid limit, a day might look like this:
- On waking: a glass of water
- Breakfast: a cup of tea or milk
- Mid-morning: a glass of buttermilk or nimbu pani
- Lunch: a katori of dal and a glass of water
- Afternoon: a glass of water or coconut water
- Evening: tea, and a glass of water
- Dinner: soup or thin dal, and a glass of water
- After dinner: a cup of warm milk
That comes to about nine or ten glasses, spread so no single moment feels like a chore.
When should you call a doctor?
Get medical advice promptly if the person:
- has passed little or no urine for eight hours or more
- becomes confused, very drowsy or faint
- cannot keep fluids down, or has vomiting or diarrhoea that does not settle
- shows signs of fluid overload while on a fluid limit, such as swelling or breathlessness
- has a wound that is getting larger, hot, red or smelly, or develops a fever
The bottom line
Most adults recovering from a wound need about 9 to 10 glasses of fluid a day, more in heat, fever or with a draining wound. Older people often need reminders, an easy cup within reach and a routine that fits around their worries. People with heart failure, kidney disease or liver disease may need a fluid limit, and that limit always comes first.
For the food side of recovery, see a day of meals for wound healing, and if eating is the struggle, what to do when someone will not eat.