Hydration and You

Just how intertwined are life and water? To get the gist of it, consider this: for decades, the search for extra-terrestrial life has been guided by one key criteria – the presence of H2O, both solid and liquid. Regardless of the motives of scientists and organisations involved in the search, none can dispute that where there is water, there is life.

But how does that concern you, a person on Earth drinking a cup of coffee at breakfast or sweating it out on your evening run? Well, it’s all about hydration. Strangely enough, hydration is not just about drinking water. It’s about maintaining the balance of water and other chemicals within your finely-tuned body.

What Goes In, Must Come Out?

To know what you need to put in your body to keep it hydrated, we must first look at the ways we lose water.

Insensible Loss (0.6 – 0.8 Litres)

Insensible loss refers to water loss that isn’t noticeable to us, hence ‘insensible’ or ‘not sensed’. This category includes water loss through moisture in the air we exhale (respiration) and the minute amount of moisture that evaporates through our skin (not perspiration). Here, the average human loses between 600 – 800 millilitres a day, depending on individual activity level and atmospheric humidity.

Perspiration (0.2 – 5.7 Litres)

There is a wide range for this category depending on your work environment and lifestyle. Office workers in an air-conditioned environment can expect to lose as little as 200 millilitres of water in perspiration, while those employed outdoors can generate as much as 5700 millilitres of water over eight hours of work.

Surprisingly, in a hot and wet climate like Singapore’s, people tend to perspire less than in a hot and dry climate like Australia’s. However, this is not a good thing – the lower rate of perspiration is commonly attributed to sweat gland fatigue and an ‘overly-wet’ skin, since a humid atmosphere means less efficient evaporation and cooling. Without proper monitoring of your physical state, heat stroke and acute dehydration is a very real and dangerous possibility.

Bodily Waste (1.7 Litres)

Urination is the largest outlet of bodily water for most people. The average person loses 1500 millilitres of water through urine and 200 millilitres through faecal motion.

Ok, Now What Goes In?

The daily intake of water for the average person is roughly in the ratio of 1:3:6 for water obtained through metabolism, food, and beverages respectively. Metabolism refers to the bodily processes which break down chemicals to maintain a healthy biological balance in the body, producing water as a by-product.

For the average person who takes in 2500 millilitres of water, 250 millilitres comes through metabolism, 750 millilitres through food, and 1500 millilitres through water and other drinks.

Is That It?

If it were as simple as that, this would be a wonderfully brief article. However, reality is often more gnarly and can’t be comprehensively captured in notes and numbers. Your personal assessment is crucial in determining if you are at a healthy level of hydration.

Too Much of a Good Thing

Dehydration is obviously not a good thing, unless you’re a strip of beef jerky or preserved fruit. At the extreme end of the scale, drinking too much water can result in water intoxication, known as hyponatremia. The excess amount of water in your body greatly dilutes the concentration of sodium in your blood and cells – sodium which is indispensable for brain and muscle function – resulting in symptoms such as headaches, giddiness and confusion, seizures, and in extreme cases, death.