Hydration
Life's essential solvent. Your body is 60% water by weight, and every cell needs it to function. Water regulates temperature, cushions joints, transports nutrients, removes waste, and enables virtually every metabolic reaction. Chronic mild dehydration is surprisingly common and causes subtle dysfunction.
What Water Does in the Body
Solvent for Reactions
Most biochemical reactions happen in water. Enzymes need proper hydration to function.
Temperature Regulation
Sweating cools you down. High heat capacity buffers temperature changes.
Nutrient Transport
Blood is mostly water. Carries nutrients, oxygen, hormones throughout body.
Waste Removal
Kidneys need water to filter waste. Urine, sweat, breath expel toxins.
Joint Cushioning
Synovial fluid lubricates joints. Dehydration = stiffer, more painful joints.
Brain Function
Brain is 75% water. Even mild dehydration impairs cognition, mood, memory.
Signs of Dehydration
Early Signs
- Thirst (already mildly dehydrated)
- Dark yellow urine
- Fatigue, low energy
- Headache
- Dry mouth and lips
- Reduced urine output
Severe Signs
- Dizziness, lightheadedness
- Rapid heartbeat
- Confusion
- Sunken eyes
- Very dark urine or none
- Fainting
How Much Water Do You Need?
General Guideline
Half your body weight in ounces. 150 lbs = 75 oz (~2.2L). More if active, hot, or ill.
Urine Check
Pale yellow = good. Dark yellow = drink more. Clear = possibly too much.
Increase for...
Exercise, hot weather, fever, illness, high altitude, caffeine/alcohol consumption.
Include Electrolytes
Plain water not enough if sweating a lot. Add salt, minerals to prevent dilution.