Keeping your brain hydrated!

Water is quite literally the source of life! It forms around 60- 80% of our bodies and is needed for a variety of different functions like regulating our body temperature and keeping certain areas (like our eyes!) moist. We also know that remaining hydrated can help us to prevent constipation, dry skin and even reduce hunger but could it have a big impact on our brain health too?

Before we get stuck into the benefits of keeping our brain hydrated though, let’s start with the basics…

How much water should we be drinking?

In the UK, it is generally agreed that 6- 8 glasses of fluid a day is a pretty good place to start on your journey to being a hydrated human. Yes, that recommendation is pretty vague, but it’s because your hydration needs can easily be impacted by: the weather, how much you sweat, your exercise routine and even your body size!

If you want to be a little more specific, some health professionals use a hydration calculation based on your body weight.  To do this calculation for yourself, you need to multiply your weight (in Kg) by 0.033 and this will give you the amount in litres that you (probably) should consume. For example, if you are 60kg, you should drink about 2 litres of water every single day. At 90kg, you’ll need around 3 litres of water.

So why is being hydrated important for our brain?

With around 75% of our brains being made up of water, as you can imagine, hydration is pretty important. Brain cells require a delicate balance between water and various elements to operate, and when you lose too much water, that balance is disrupted and your brain cells lose efficiency.

In fact, studies show that even mild dehydration, such as the loss of 1–3% of body weight, can impair many aspects of brain function. In one study of young women, researchers found that just 1.4% loss of fluid through exercise reduced both mood and concentration (1). Similarly, another study found that a fluid loss of 1.6% of body weight was enough to provoke feelings of fatigue and anxiety (2).

This link between dehydration and a reduction in mood and cognition is thought to impact all age ranges. Those in more vulnerable groups though, like children and the older population, are thought to be impacted the most by dehydration though as their brains are often under more demand when completing cognitive tasks (3).

Although it might not be the easiest thing to calculate your own fluid loss percentage, a good way to quickly check if you are hydrated enough, is to do a quick urine test! If your urine is clear or a very pale yellow, you’re doing a great job and your brain will (hopefully!) by running like a well oiled machine.

So now we know that even a slight drop in our hydration status could impact our mood, energy levels and even focus, let’s look at some practical and simple tricks to keep your brain hydrated.

Keep fluids accessible!

We often can’t rely solely on our thirst to let us know when to drink water but many people simply don’t ‘feel’ thirsty or they will notice their cues when it is too late… hello de- hydration headache!

To overcome this, having liquids quite literally ‘on tap’ can be a great way to keep your water levels topped up throughout the day. Maybe you could invest in a water bottle to keep on your work desk or even get a hydration back-pack for longer runs or walks.

Setting reminders on your phone or by using an app can also be a great way to remind us to drink when we might previously have forgotten too.

Eat your water!

Yes, drinking water has the most ‘water’ in it, but don’t forget that you can get plenty of water from your foods too. In fact, about 20% of our daily fluid intake usually comes from solid foods, especially fruits and vegetables like lettuce, watermelon, cucumber and celery which are jam packed with H2O!

Mix it up if needed

If you struggle to just drink water on its own, there are plenty of different options for you to make sure you’re not missing out on the extra brain power. Adding fruits or veg to water like cucumber or berries can be a great way to add flavour without any extra sugars or additives. Alternatively, herbal teas are perfect at helping you get to your water target and even teas and coffees can play a part. Even though these caffeinated delights are slightly diuretic (they might make you wee a bit more!) the water intake you take in will always outweigh what you lose.

So now that you’re armed with the knowledge, tips and (hopefully!) a water bottle, you can keep your brain running at full power as we move into the warmer days ahead of us.

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  1. Armstrong, et al., (2012) Mild Dehydration Affects Mood in Healthy Young Women, The Journal of Nutrition, Volume 142, Issue 2, Pages 382–388,
  2. Armstrong et al., (2011). Mild dehydration impairs cognitive performance and mood of men. British Journal of Nutrition, 106(10), 1535-1543. doi:10.1017/S0007114511002005
  3. Pross N(2017) Effects of Dehydration on Brain Functioning: A Life-Span Perspective. Ann Nutr Meta;70(suppl 1):30-36. doi: 10.1159/000463060