Updated: Sep 23, 2020
“3 minutes without air, 3 days without water and 3 weeks without food”
Have you heard this rule of threes often quoted by wilderness survival experts? Water is an essential nutrient; it is arguably the most important nutrient we need. Our body cannot survive more than a few days without water, whereas it may take weeks, months or years to develop deficiencies in other nutrients. I'm not suggesting that we go into the wilderness to test out this rule but I do suggest we consider our own water consumption.
So why is water so important to us?
About 60% of our body’s weight is actually #water. Water is the fluid in which all life processes occur within our cells, outside of our cells and between our cells. Water is needed to transport nutrients, including vitamins and minerals, oxygen and waste products around our body, to maintain cell integrity and structure of large molecules, to participate in metabolic reactions, to lubricate and cushion our joints, to moisten mucus membranes, to help regulate our temperature and to maintain blood volume. For our body to function optimally, fluids need to remain in balance within and outside of the cells. For this to happen, we need to ensure that we consume plenty of fluids.
Do you only drink when you feel thirsty?
You know that feeling when you have a dry mouth which prompts you to reach for a drink. Well, actually, that prompt is delayed, well-behind the body’s need to replenish its fluid supplies. If we continually ignore this prompt, are unable to find water, or are unable to recognise it (common in the elderly), our body quickly becomes dehydrated, resulting in weakness, exhaustion and, eventually, death. However, long before we feel thirsty, some of our body functions may be affected such as concentration, alertness and short-term memory. Not drinking enough water has also been linked to constipation, cystitis, increased risk of kidney stones and dry skin.
It is, therefore, essential to consume water regularly and not wait for that dry mouth or that feeling of thirst. This is especially important when exercising, when sick (particularly vomiting/diarrhoea) or when it’s hot and humid. On average, we may lose about 2.5 litres per day through urine, sweat, breath and faeces.
So what is the best form of fluid to consume?
WATER! Almost all foods will contain some form of water, with fruits and vegetables containing up to 90% water and meat and cheese containing around 50%, but water is 100% water. Consuming large quantities of beverages such as coffee, tea, soft drink or juice, will provide fluids but these are not necessarily the answer to hydrating our bodies optimally. They may be high in sugar, contributing to a myriad of other health problems, or contain caffeine/tannins, which may also adversely affect our health and wellbeing.
How much water should you be drinking?
Everybody is different; everybody will have different needs depending upon their diet e.g. consumption of fruit & veg, their activity level (e.g. athlete or sedentary), and their physical environment (e.g. temperature). Pregnant or breastfeeding women will also need more water. Some guidelines suggest that a healthy man should consume about 2.6 litres of water every day and for women approximately 2.1 litres. About 20-30% of this may come from foods depending upon your diet. Some people will go by the ‘8 glasses per day’ rule, but this may not be true for you.
Although rare, it is possible to consume too much water - the kidneys cannot cope causing an imbalance in sodium levels, resulting in headaches, blurred vision, cramps, swelling of the brain, coma and possibly death. For most people this is unlikely to happen, as many litres need to be consumed in a short period of time. The most likely groups of people to suffer water intoxication are those with mental diseases like schizophrenia, endurance athletes and formula-fed infants when the formula is incorrectly diluted.
One of the best ways to know whether you are drinking enough is to check your urine colour. If your urine is lightly coloured or clear, then you’re drinking enough but if it’s dark, then you need more water.
Tips to increase your water consumption
Keep a reusable bottle or glass on your desk at work or on the kitchen benchtop at home
Do not leave the house without a reusable bottle of water in your bag or car
Keep a jug of water in the fridge or some ice cubes to cool your water on a hot day.
Add a squeeze of fresh lemon, lime or orange juice to water to vary the taste
Have a large glass of water as soon as you wake up in the morning
Better Health Channel, (2018), Water a vital nutrient. Retrieved from: https://www.betterhealth.vic.gov.au/health/healthyliving/water-a-vital-nutrient
Whitney, E et al, (2014) Understanding Nutrition. Cengage: South Melbourne. p. 367-372