- Dr. Shamim Ara
There is obviously no one in the earth who may have not heard the advice for drinking a lot of water. Not only physicians , nutritionists , dieticians or beauticians; this advice is regularly given by our friends and families. Why do we need to drink a lot of water everyday? One of the key reasons is- human body does not have any mechanisms to store water in normal condition so the amount lost everyday need to be replaced appropriately.
Water has a lot of important functions in human body like:
- Regulating internal-body temperature
- Removal of waste through urination, defecation, perspiration,sweating
- lubrication of joints
- Aids in digestion
- Activates metabolism
- Helping to prevent constipation
- Improves blood oxygen circulation
- Keepsskin , hydrated & bright
- Maintains nail & hair
The body composition of a young adult male of around 70 kg weight is as follows:
- 60% (around 42 liters) is water
- 18% is protein and related substances
- 7% is mineral
- Rest 15% is fat
About 28 of the 42 liters of water in the body are distributed inside cells, collectively called intracellular fluid, which in average covers 40% of total body weight.
Extracellular fluid (water outside the cells) account for 20% of the total body weight or about 14 liters in usual 70 kg weighted man.
The proportion of water changes depending on age, gender and degree of obesity. Females usually have more body fat than males, so water in their bodies cover 50% of body weight. For newborn babies, 75% of the body is water. People with more fatty tissues have less amount of water than people with less fatty tissues.
In adult about 2300 mL of water is lost every day in different manners, as mentioned below:
- Through skin: 350 mL
- Through lungs: 350 mL
- Through sweat: 100 mL
- Through faces: 100 mL
- Through urine: 1400 mL
Among these, water loss from skin and lungs are considered insensible, since these occur continually in all living humans without our conscious awareness.
Daily water intake comes from two major sources:
- intake of water in the form of liquids or through water in the food, which together normally make about 2100 mL/day to the body fluid.
- water is synthesized in the body as a result of metabolism adding 200 mL/day.
So total water intake in our body is around 2300 mL per day.Intake of water and also daily loss of water depends on climate, habits, level of physical activity etc.
Each day everyone must consume certain amount of water. This varies according to age, gender and climate. Generally adult male needs about 3litres water/day and adult female 2.2liters water/day.20% of this water we get from food we eat. The rest is dependent on drinking water and water bound beverages.
It is needless to mention how important water is for us. Life and water are compliments of each other.It is utmost important for young professionals particularly to take sufficient water, keeping in mind their own attributes and corresponding needs (as discussed in details above). So, everyone needs to ensure adequate intake of water every day.
The author is an MBBS, MPhil ,FCPS(Honorary) and Professor of Anatomy, Holy Family Red Crescent Medical College and also a retired Professor of Anatomy, Dhaka Medical College.