Water is the most vital nutrient for the human body and is required for majority of our bodily functions. We cannot survive much longer than a few days without it. Our bodies are made up of between 55 and 75% water, and adults can lose up to 3 litres of water per day. As our bodies are not particularly good at storing large volumes of water, it is essential that water loss is replenished daily.

Drinking plenty of fresh water throughout the day is your best bet for staying hydrated, however you don’t necessarily need to be gulping down litres and litres and litres. We also obtain water from the foods we eat — fresh fruit and vegetables are a particularly excellent source of water. Plus, they also provide a lovely dose of vitamins, minerals and fibre. Small amounts of water (250-300 mL) are also produced by metabolic processes in the body each day.

The amount of water we each need be drinking daily is slightly different for everyone, and it will vary for each individual on a day-to-day basis. There are a number of factors that can impact on water loss such as physical activity, climate, relative humidity, medications, episodes of vomiting or diarrhoea, pregnancy, breastfeeding and even the types of food you are eating. So, how do you know if you are well hydrated or not? One easy way is look at and think about your urine — I know, not the most pleasant of thoughts, but please stick with me.

Frequency: How often have you urinated during the day? If you have only been once, maybe twice by the end of the day, then you probably need to up your water intake.
Volume: How much urine are you passing when you go to the toilet? If it is little more than a dribble, then maybe add a few extra glasses of water.
Colour: If you are adequately hydrated your urine should be a very pale yellow or straw colour. If it is a darker yellow colour, you probably need to up your water intake.

*Supplemental B vitamins will turn your urine a bright yellow colour, which is normal. However, this colour change means that urine colour will not be an accurate indicator of hydration status. Urinary frequency, volume and colour should only be used as a general guide for hydration levels, not a diagnostic tool.

If you are concerned about dehydration, particularly in infants, young children or the elderly, seek medical help immediately.

Water is essential for so many processes in our body. So, here are 7 common complaints I often see in clinic, that generally improve with an increase in hydration levels:

1. Reduce fatigue and boost energy levels

Adequate fluid intake is essential for maintaining the integrity and function of cells, particularly skeletal muscle cells. Without sufficient water, cells are not able to receive nutrients or get rid of metabolic wastes as effectively.

2. Improve cognitive functioning and mood

Mild to moderate dehydration has been shown to reduce cognitive abilities such as attention span, short-term memory, numerical ability and psychomotor function. Inadequate hydration can also interfere with neurotransmitter systems, in turn affecting mood.

3. Aid weight management

Sorry folks, but water is not the magic bullet for weight loss. However, ensuring that you are getting enough fluids can help to keep your kilojoule intake in check. Thirst and hunger signals are controlled by the same part of the brain (the hypothalamus), which is why sometimes the two signals can be confused. An easy way to side-step this confusion is to have a glass of water if you think you are hungry, wait 10-15 minutes and then see if you are still hungry.

4. Decrease the risk of urinary tract infections (UTIs)

Inadequate water intake is associated with an increased risk of developing a UTI, particularly in women. Increasing your water intake will increase the flow of urine through the bladder, flushing out those nasty bacteria that have taken up residence in your urinary tract.

5. Support cardiovascular function

Water is the primary component of blood plasma and accounts for approximately 50% of total blood volume. Plasma is responsible for maintaining blood pressure and the transport of nutrients, hormones and enzymes around the body. Without sufficient levels of hydration, plasma cannot carry out these task as efficiently. Studies have shown that low intake of water is associated with increased risk of coronary heart disease, which is possibly linked with the increased viscosity (thickness) of the blood.

6. Maintain normal bowel function

Our bowels are one of our main toxin elimination routes, so it is essential to keep them moving. Everyone knows the importance of fibre in keeping us regular, but did you know that water is just as important? Fibre helps to form the bulk of the stool, but it also absorbs quite a bit of water — which means if you are not drinking enough fluids you run the risk of clogging up. Maintaining hydration levels will soften the stool, allowing for a smooth transition right the way through your gut.

7. Skin

Again, this one is no magic bullet for flawless, wrinkle-free skin. But, if you are not getting enough water your skin will suffer. Researchers have shown that maintaining adequate water intake and hydration levels improves both superficial and deep epidermal hydration as well as increasing skin elasticity.

With summer is just around the corner and predictions that we are in for a hot, dry season, now is the perfect time to get your hydration levels in check. Keep it simple — there is no need to meticulously record exactly how much water you are consuming. Just be mindful that you have water at regular intervals throughout the day and that you are eating plenty of fresh, hydrating fruits and vegetables. It takes time to create a habit of regularly drinking water, so a water reminder app can be really useful. Every so often, check in on your hydration levels by looking at the colour, volume of your urine and how frequently your are going. Adjust your water intake as needed and enjoy the health benefits of being hydrated.

View references

Chan, J et al. 2002, ‘Water, Other Fluids, and Fatal Coronary Heart Disease’, American journal of epidemiology, vol. 155, no. 9, pp. 827-833.

Jéquier, E & Constant, F 2010, ‘Water as an essential nutrient- the physiological basis of hydration’, European journal of clinical nutrition, vol. 64, no. 2, pp. 115-123.

Masento, N et al. 2014, ‘Effects of hydration status on cognitive performance and mood’, British journal of nutrition, vol. 111, no. 10, pp. 1841-1852.

Mattes, R 2010, ‘Hunger and Thirst- Issues in measurement and prediction of eating and drinking’, Physiology and behaviour, vol. 100, no. 1, pp. 22-32.

Palma L et al. 2015, ‘Dietary water affects human skin hydration and biomechanics’, Clinical cosmetic an investigational dermatology, vol. 3, no. 8, pp. 413-421.

Popkin, B et al. 2010, ‘Water, Hydration and Health’, Nutritions reviews, vol. 68, no. 8, pp. 439-458.


Sarah Woolner

I’m Sarah — a qualified naturopath and food enthusiast. I am currently practicing on Sydney's Northern Beaches, in Brookvale and Mosman. If you would like to make an appointment please send me an email via the contact page.

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