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Water - The Importance of Staying Hydrated

Our bodies are about 60% water and water is absolutely fundamental to every aspect of our body’s functioning. Survival experts say that we can last about three days without water during which time you would expect to see a steady deterioration in our wellbeing from the initial feelings of thirst suggesting the onset of dehydration, to the seizures and loss of consciousness that comes with severe dehydration.


Less dramatically than this, many of us are constantly under-hydrated and this leads to us operating less effectively at every level of our biology, from the cellular level right up to our ability to perform complex, cognitive tasks. 

Why is water so important?

Water is really the fundamental building block of our physiology. The plasma in our blood is mostly water and it is the movement of this fluid that transports the blood cells, dissolved electrolytes, and important proteins around the body with every beat of our heart. 


Water is vital for us to maintain our body temperature (through sweating), for our digestion (as the basis for saliva and gastric juices), for providing the lubrication to our joints (in synovial fluid), for allowing toxins to removed from our body (in urine), and for providing the protective layer of fluid around our brain and central nervous system. 

What happens when we are dehydrated?

When we are short of water, things start going wrong throughout the body. Common symptoms of dehydration that many people live with all the time include headaches, constipation, and feeling tired, dizzy, or lightheaded. Being chronically dehydrated can also predispose you to other problems such as the development of kidney stones or urine infections. The risk of developing urine infections is a particular issue amongst older people who often drink less than is recommended and tend to be at higher risk of infection in any case. For this reason, many care homes have instigated regular drinks rounds to encourage their residents to drink more fluid, particularly water, in order to keep them safe.

lady with headache

How much water should we be drinking?

Keeping hydrated is really important. Adults are recommended to drink between 1.5 to 2L of fluid each day. This doesn’t have to be water but can be any kind of fluid including fruit juices, cordials, soft drinks, even tea and coffee, but you should be careful to avoid drinks that contain too much sugar to avoid other significant problems like dental decay, obesity, or diabetes. Also note that alcoholic drinks do not count as these will actually dehydrate you due to the diuretic effect of alcohol. You should increase the amount of fluid you drink above 2L if you are exercising, the weather is hot, or if you are unwell with diarrhoea and vomiting. 

lady drinking water

How to tell we are drinking enough water?

The simplest way to assess whether you are adequately hydrated and drinking enough water is by checking the colour of your urine. Ideally, your urine should be a pale straw colour. Any darker than this, then you are probably not drinking enough water.

toilet bowl

Hydration status can be more formally assessed with blood tests. Generally, renal function tests are used to check this. Two important markers are used when checking renal function – urea and creatinine. The urea tends to rise first when people are becoming dehydrated. If the situation becomes more severe then the creatinine will start to rise and this will be reflected by a fall in the ‘estimated glomerular filtration rate’ (eGFR) which is the biomarker that is most commonly used to assess overall renal function. In very severe dehydration you may also see high levels of sodium and potassium as the blood becomes more and more concentrated. 

If you find that your eGFR is low, this may be an acute problem – sometimes called an Acute Kidney Injury – reflecting that something is wrong right now that has caused you to become dehydrated, or it may be that you have Chronic Kidney Disease which is a long term deterioration in kidney function.


See our article on Chronic Kidney Disease: what it means for me?


Either case should be followed up by your doctor but, if you are feeling unwell and your eGFR is low, you should seek urgent medical attention.


So, staying hydrated is important for both your long-term and short-term health. The value of keeping up with the recommended water intake is not to be underestimated.

Nutrition and Hydration Week

Nutrition and Hydration Week is an annual event that aims to highlight, promote, and celebrate improvements in the provision of nutrition and hydration.


This year’s edition will take place from March 11th to March 17th, 2024 


Monitor your health with One Day Tests

One Day Tests offer you the power to monitor and understand your health like never before. Whether it’s for routine health checks, managing a chronic condition, or just staying informed about your body, our range of blood tests provides the convenience, accuracy, and peace of mind you deserve.


Whether you choose to visit a clinic for your blood work or opt for the convenience and comfort of using our at-home blood test kits , we ensure a service that is not only dependable but also tailored to suit your preferences.


For additional assistance, guidance or queries regarding our custom panels, do not hesitate to get in touch. Our team is here to help you with any questions and provide you with the information you need. You can contact us at 0845 527 07 67 , send an email to hello@onedaytests.com , or reach out to us via WhatsApp.


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