A health principle that everybody is familiar with is to drink eight glasses of water per day. If you consider that two-thirds of the adult body is made up of water, the need for the life-giving fluid is actually very clear. But how much water should we really be drinking every day? It seems the answer to this simple question doesn’t have a simple answer.
Why We Need Water
Water is essential as every cell, tissue and organ needs water to function optimally. This includes most of your brain, heart, lungs, muscles and skin, and even about a third of your bones. Water is needed for the following:
- transport nutrients,
- regulate our body temperature,
- form bodily fluids (e.g. blood and saliva),
- lubricate the joints,
- cushion our organs, and
- eliminate wastes though urine, bowel movements, breathing and sweating.
Being dehydrated means an imbalance of water in the body either because of more water losses than normal or through higher water needs. Water can be lost when taking certain medications like diuretics, during illness such as having a fever, vomiting or diarrhoea, in hot or humid environments, or when exercising for long periods and/or at high intensities. Water needs are also higher in pregnant and breastfeeding women or in conditions like constipation or kidney stones. Studies have shown that dehydration of as little as 2% (the same as a 1.6L water loss in an 80 kg person) can affect the body. Other physiological functions affected include functions of the brain, gut, kidneys and heart (related to blood volume), as well as headaches and skin health.
How Much Water Do We Need?
The age-old advice to drink eight glasses of water per day, while practical and easy to remember, is questioned by many healthcare professions. This rule may be too simplistic to say that every person, regardless of weight, height, activity level or environment needs the same amount of water. The advice to drink to thirst is also criticised as we can learn to override our thirst mechanism.
According to the Dietary Reference Intakes (DRIs) for Water, the average adult man needs 3.7 L of water and the average adult female needs 2.7 L daily, more if pregnant (3.0 L) or breastfeeding (3.8 L). Perhaps the best advice would be to regularly drink water throughout the day, with more attention placed on water when needs are higher. A good rule of thumb is to use the colour of your urine to judge if you’re dehydrated. Aim for light-coloured urine and avoid apple juice-coloured urine.
Beyond Water: where do we get additional fluids?
The National Board of Nutrition published the DRIs report that – 80% of our water needs should be met with plain water, and 20% should can come from some foods and beverages. Water-rich foods tend to be fresh fruits and vegetables, which are evidently good for our health in more ways than we realise. However, although other drinks such as teas, coffees, juices and coldrinks also contribute to the total fluid intake, it is important to remember that plain water should make up the bulk of your total fluid intake.
Ways with Water
For some, drinking plain water isn’t tasty, while for others, getting into the habit of drinking water is the biggest challenge. Here are some practical tips to help you stay hydrated:
- Make it a rule to always drink a glass of water with every main meal, and with snacks too if you’re a snacker.
- Always keep a visible source of water within arm’s reach, whether in a jug or a bottle. For example, make a habit of placing a jug of water on your desk as you get to work every day. Have water bottles in gym bags, handbags and the car.
- Still or sparking water can both add to your daily water quota. So can herbal or Rooibos tea (without milk and sugar) and hot water, with or without a squeeze of lemon juice.
- Add flavour to plain or sparkling water with fresh fruit (e.g. diced apples, assorted berries, orange slices), freshly squeezed or bottled water, or herbs (e.g. mint, basil, rosemary).
- Make healthy homemade iced teas: Steep four caffeine-free teabags (e.g. Rooibos) with every 1 L of hot water. Once cool, remove the tea bags and add one of the above-mentioned flavours. Serve as a drink or pour into ice lolly moulds for a refreshing summer dessert.
- Freeze mint or lemon slices in ice trays to serve with water on hot days.
- Download a free water reminder app on your smartphone to help you form healthy water drinking habits in a fun way.