Water: Just how much do we need it?

Water: The Vital Nutrient

This week is National Nutrition and Hydration Week, a global movement aimed at promoting the importance of optimum nutrition in avoiding malnutrition and hydration related illnesses.

While the focus of this campaign is on health and social care settings, anyone can be vulnerable to the effects of dehydration, which can range from fatigue and mood swings, to increased risk of kidney stones and hypertension (1).

Are you dehydrated?

A recent national study found that 30% of adults and 50% of children in the UK fail to drink the recommended amount of fluid each day (2). The effects of mild dehydration are therefore likely to affect many of us in the UK. The most common symptoms are:

  • Tiredness and fatigue – Fluid losses mean that your heart has to work harder to pump blood round your body (3).
  • Low mood and anxiety – Mild dehydration affects mood, possibly as a result of altered neuronal activity in the brain (3).
  • Headaches – Just 1% dehydration has been found to lead to headaches in young women (4).
  • Poor cognitive performance and memory – Being dehydrated by just 2% impairs attention span and short term memory (5).

These symptoms are felt at just mild levels of dehydration, which can occur even before you start to feel thirsty.

The amount of water needed to avoid dehydration depends on your height and weight, activity level, and the current climate. A general guideline is that men should drink at least 2 litres of beverages each day, while women should aim to drink at least 1.6 litres – and more if it’s a hot day or if you are exercising.

Choose your drinks wisely

While all beverages count towards your fluid intake, some drinks offer more benefits than others. Sugary drinks can lead to unwanted weight gain, while caffeinated drinks have diuretic properties and can upset energy levels. Good choices are herbal teas and of course, fresh water.

Pukka Teas

Water Enhancers

Those who don’t enjoy drinking plain water can add a squeeze of lemon or lime, or some crushed mint. Alternatively, filtering tap water can improve the taste by removing chlorine, as well as filtering out other contaminants such as copper, mercury and cadmium.

If you are upping your water intake, be aware that most bottled water is supplied in bottles made with a material called bisphenol-a (BPA), a toxic substance that can leach into the water. Drinking from glass bottles, or using a BPA-free water bottle is a sensible measure.

BPA-Free BRITA Filter Range

Daily Hydration Strategies

It can be easy to forget to drink water on a busy day. However, simple habits can go a long way towards ensuring you are properly hydrated. Try the following tips:

  1. Drink a glass of water as soon as you get up in the morning.
  2. Ask for a glass of water every time you order a tea or coffee in a cafe or restaurant.
  3. Carry a bottle filled with filtered water every time you leave the house.
  4. Keep a bottle of water on your desk at work.
  5. During exercise, drink every 10-15 minutes.

Water is an often overlooked nutrient, and yet it makes up around two thirds of our body. Paying proper attention to water intake is one of the simplest and most effective ways to look after our everyday health and wellbeing.

1. Man (2007) Hydration and disease. J Am Coll Nutr 62(5):535-541
2. Gandy J (2012) First Findings of the United Kingdom Fluid Intake Study. Nutrition Today. 40(4):14-16
3. Ganio et al (2011) Mild dehydration impairs cognitive performance and mood of men. Br J Nutr 106(10):1535-43
4. Armstrong et al (2012) Milk dehydration affects mood in healthy young women. 142(2):382-8
5. Adan A (2012) Cognitive performance and memory. Am J coll Nutr 31(2):71-2