Hydration needs are very individualized. Factors that affect hydration needs include your age, gender, size, exercise habits, e.g., type, duration, intensity, and also the climate you exercise in. Below are general recommendations for males and females WITHOUT consideration for exercise:
- Males: 125 ounces (4 liters, or roughly 1 gallon) per day
- Females: 96 ounces (3 liters) per day
For every 15 minutes of exercise, you need to INCREASE fluid intake by 5 – 10 ounces.
If exercising outside in a hot climate, or living in a warm climate, consider increasing total fluid consumption by 5 – 10%. In the example above, that means increasing fluids an additional ~5 – 15 ounces per day.
Remember that some of the foods you eat, particularly fruits and vegetables, also contain water. These recommendations are based on a combination of water, milk, and other beverages and food you consume, NOT just water alone. Remember to keep sugary drinks (consumed outside of training) to a minimum.
If you’re drastically under-hydrating, start with small steps towards your goal—don’t try to skip to your daily target overnight: your bladder won’t be happy. Aim to increase your daily intake over the next 1 – 2 weeks, until you’re consistently near your daily target.
If a female exercises for 60 minutes, she needs to consume an additional 20 – 40 ounces per day, bringing her daily total to 116 – 136 ounces