Water loss in the body occurs through urination, bowel movements, sweating and respiration. The best way to replenish the water supply is to drink water and other liquids as well as eating water-rich foods.
The issue is how much water should be drunk daily to prevent dehydration. Doctors from Mayo Clinic suggest several approaches for average healthy adults living in temperate climates.
Drink Eight 8-ounce Glasses of Water Daily
This is the most commonly recommended and known approach to keep the body hydrated. Eight 8-ounce glasses of water makes about 1.9 liters of water. However, it does not necessarily have to be water that’s drunk although water is the preferred drink. Other liquids such as fruit juices, tea and coffee count towards the daily total as well.
Adopt the Replacement Approach
The average adult passes out approximately 1.5 liters (6.3 glasses) of urine daily. Another liter of water is lost each day through respiration, perspiration and bowel movements. That’s about 2.5 liters of water loss each day. Food intake typically contributes around 20% of the body’s total fluid intake. That means if a healthy adult drinks 2 liters (8 glasses) of water and other liquids a day along with his usual food intake, he will be able to replace the lost fluids successfully.
Use Thirst to Determine Fluid Needs
The Institute of Medicine says that healthy adults can also use thirst to determine their fluid needs. If an adult rarely feels thirsty and has relatively clear urine, his fluid intake is probably enough.
When Water Intake Needs Modification
The approaches mentioned above apply to normal healthy adults. However, there are exceptions to these rules.
- Strenuous physical activities. Athletes and active people need to drink more water to replace the lost fluids. Additional 400ml to 600ml of water is usually enough for short sessions of physical activities. However, those who engage in strenuous activities such as marathons, triathlons and long tennis matches will need to drink even more fluids.
- Certain medical conditions. Those with bladder infections, gastroenteritis, frequent vomiting and diarrhea should increase their water intake. However, water intake should be limited in other conditions such as some heart, kidney and liver diseases that adversely affect water excretion.
- Pregnancy and breastfeeding. Expectant and breastfeeding mothers should drink more water too. Increased water loss occurs particularly during breastfeeding. According to the Institute of Medicine, the recommended daily water intake for expectant and breastfeeding mothers is 2.3 liters (10 glasses) and 3.1 liters (13 glasses) respectively.
- Extreme living conditions. Those who live in hot and humid places sweat more, increasing their need to drink more water. People who live in highlands or areas 2500 meters (8,200 feet) above sea level also experience more frequent urination and faster breathing, activities that require increased water intake.
Lost fluids in the body should be replaced promptly for optimal health. Doctors recommend drinking eight 8-ounce glasses of fluid daily. Using the replacement approach and thirst to determine fluid needs have also been recommended. However, certain circumstances such as strenuous physical activities, medical conditions, pregnancy and breastfeeding as well as extreme living conditions will need water intake to be modified.
Those who find this article useful may also like to read Health Benefits of Water and Fluid Sources for the Body.
Wei Yin Wong - I started my working life as a reporter at an English daily called The Sun in Malaysia 16 years ago, writing health-related articles. ...
