The Importance of Hydration When Rowing

The importance of hydration when rowing is simple: lose too much fluid and the same pace costs more effort. Start sessions hydrated, sip during anything over an hour, and replace what you lost afterwards. For most sessions under an hour, plain water is all you need, and drinking far more than you sweat brings its own risk.

Why fluid matters

When you row hard, you generate a lot of heat, and sweat is how you lose it. If you lose a lot of fluid and do not replace it, your blood volume drops slightly, your heart works harder at a given pace, and the session feels harder than it should. On a hot day, or in a room with no airflow, the effect is bigger.

The American College of Sports Medicine treats a loss of more than 2% of body weight as excessive, and says drinking during exercise should aim to prevent it. For an 80 kg rower that is 1.6 kg. Its position stand on fluid replacement also says sweat rates vary between people, so a personal plan beats a single number.

How much to drink each day

The NHS guide to water and drinks suggests 6 to 8 cups or glasses of fluid a day, and more if you are active for long periods. Water, lower-fat milk and lower-sugar drinks all count, as do tea and coffee. The better check is colour: aim for clear pale yellow urine.

A simple routine

These figures draw on British Rowing nutrition guidance. The example is a 75 kg rower.

When	What	Example
Daily	6 to 8 glasses	More on training days
With the meal before training	5 to 7 ml per kg	375 to 525 ml
With the snack before training	3 to 5 ml per kg	225 to 375 ml
During, under an hour	Sips as needed	Water
During, over an hour	Regular sips	Consider a 6% carbohydrate drink
After	1.5 litres per kg lost	0.8 kg lost = 1.2 litres

Do not drink all of that after-training figure at once. Spread it across the next few hours, with food.

Work out your own sweat loss

The ACSM says body weight before and after exercise gives a usable estimate. Try this a few times in different conditions.

1. Weigh yourself in minimal clothing just before training.
2. Row your normal session and note how much you drink.
3. Towel dry and weigh yourself again straight after.

Each kilogram of weight lost roughly equals a litre of fluid lost. Here is a worked example with made-up numbers.

Measure	Value
Weight before	80.0 kg
Weight after	79.2 kg
Weight lost	0.8 kg, or 1% of body weight
Drunk during	0.5 litres
Total sweat loss	0.8 + 0.5 = 1.3 litres
Drink afterwards	0.8 x 1.5 = 1.2 litres

If you weigh more after a session than before, you drank too much. Cut back.

Use the result as a guide for similar conditions, not as a rule. A session in a warm garage will not match one on a cold river.

Water, carbohydrate and sugar

For sessions under an hour, plain water is normally enough. The same goes for short extras such as a walk for rowing training or a yoga routine for rowing performance. For longer or harder efforts, a drink with about 6% carbohydrate gives you 60 g per litre, and our guide to fuelling for long-distance rowing shows how that fits a long row. If you want the bigger picture on food and the erg, read how your diet affects rowing machine performance.

Watch sugary soft drinks as an everyday choice, since they add calories without much else. The NHS limits fruit juice and smoothies to one small 150 ml glass a day, ideally with a meal.

Electrolytes

You lose sodium and other minerals in sweat. An electrolyte drink can help in long or hot sessions, and salty food after training also replaces sodium. Practise in training first, because strong or very sweet mixes can upset your stomach. Some people lose more salt than others: white marks on your kit after a session are a hint that you are a salty sweater.

Caffeine and alcohol

Caffeine in normal amounts is usually fine, and tea and coffee count towards your fluids. Avoid taking it late if it hurts your sleep. Our guide to rowing diet and mental health looks at how caffeine, sleep and mood fit together. Alcohol interferes with sleep and slows recovery, so keep it away from the hours either side of hard training.

Food counts

A good part of your fluid intake comes from food: fruit, vegetables, soups and porridge all contribute. Salty foods such as a sandwich, soup or salted nuts after a long session help you hold on to the fluid you drink. Plan for it around long events, when you need both fuel and fluid.

Overdrinking

Drinking far more than you need can dilute your blood sodium, which is dangerous in its own right. It is most likely in long, slow efforts when you drink on a schedule. Drink to thirst in long sessions, use the weigh-in check above, and never force fluids.

Hot weather and open water

On the water you can forget to drink because you are busy rowing. Carry a bottle in the boat where possible, and take extra care in summer. On the erg, put a bottle where you can reach it without breaking your stroke, and add a fan. Our nutrition hub has more on fuelling.

If you have a heart or kidney condition, or take medication affecting fluid balance, ask your GP before changing how much you drink. Persistent headaches, dizziness or confusion after exercise need medical attention.