Hydration: The Simple Basics Most People Get Wrong

Mild dehydration affects cognitive function, physical performance, and mood — and most people walk around chronically mildly dehydrated.

Hydration: The Simple Basics Most People Get Wrong

Mild dehydration — as little as 1–2% of body weight in fluid — measurably impairs cognitive function, physical performance, and mood.

Most people walk around chronically mildly dehydrated. They have been for so long that it feels normal.

How Much Water Do You Actually Need

The commonly cited 8 glasses (2 litres) per day is a reasonable baseline, but it does not account for:

• Body size — larger people need more
• Activity level — training increases fluid requirements significantly
• Climate — hot or humid environments increase loss through sweat
• Caffeine and alcohol intake — both are diuretics

A practical daily target for most active adults: 3–4 litres per day, including fluids from food.

The simplest indicator: your urine should be pale yellow. Dark yellow or amber indicates dehydration. Clear and colourless can indicate overhydration.

Signs You Are Chronically Dehydrated

• Persistent fatigue
• Frequent headaches
• Brain fog and poor concentration
• Dry skin
• Constipation
• Cravings for sugar (often a signal of low energy from dehydration)

How To Stay Hydrated Consistently

Start immediately. A large glass of water first thing in the morning, before coffee. Your body is dehydrated after hours of sleep.

Carry a water bottle. Hydration is a proximity game. If water is in front of you, you drink it. If it is not, you do not.

Set reminders. Until hydration becomes habitual, external prompts help.

Eat water-rich foods. Cucumber, watermelon, tomatoes, and leafy greens all contribute meaningfully to daily fluid intake.

Drink more around training. Add at least 500ml of water per hour of training, replacing electrolytes for longer sessions.

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