How Much Water Should You Really Drink Daily? The Science Behind Hydration

The commonly cited "8 glasses a day" rule is a simplification that doesn't account for individual differences. Here's what current research actually recommends:

The Body Weight Formula

A more accurate guideline is to drink 30–35 ml of water per kg of body weight daily. For example, a 70 kg person should aim for approximately 2.1–2.4 liters of water per day.

Factors That Increase Your Water Needs

• Climate: Hot and humid weather (like most of India) increases fluid loss through sweat, requiring 500ml–1L more daily.
• Physical Activity: Add 500ml for every 30 minutes of moderate exercise.
• Pregnancy/Breastfeeding: Women need an additional 300–700ml daily during these periods.
• Illness: Fever, vomiting, or diarrhea significantly increase water requirements.
• Altitude: Higher altitudes cause faster breathing and increased urination.

Signs You're Not Drinking Enough

Dark yellow urine, persistent headaches, fatigue, dry skin, and dizziness are all common signs of dehydration. By the time you feel thirsty, your body is already 1–2% dehydrated.

Pro Tip

Start your morning with 500ml of room-temperature water to kickstart your metabolism. Keep a Bislaim 1L bottle at your desk and aim to finish it before lunch — this simple habit ensures you're consistently hydrated throughout the day.