Your body is about 70% water and you only need to lose 1% of that to be dehydrated. What does that mean when it comes to our daily consumption?

How much water should you drink?

Do you know how much you weigh in kilograms? If you multiply that by 30 you get the amount of water you need daily in millilitres. If you are overweight then you need to work out what your ideal weight would be and then multiply that by 30.

30 x body weight in kg = daily water requirement in millilitres

If you weigh 70kg you need 2100mls water – minimum. This is in addition to your tea and coffee. They contribute a little but not a lot.

Bear in mind that if you are unwell, the weather is hot, you are exercising, in central heating or air conditioning then your requirement increases.

When is the best time to drink water?

You are at your most dehydrated when you wake up in the morning so that is the time to start. I suggest you have at least one glass as soon as you wake up before you have any tea or coffee.

Throughout the day you can attach your drinking to existing habits like making tea, eating meals, going to the toilet, coming in from a walk, exercising etc. By doing it this way you are more likely to stick to it according to James Clear, the author of Atomic Habits.

  • Take a glass or bottle of water to bed with you to drink when you wake up.
  • Have a glass next to the kettle to remind you to have a drink when you are making tea.
  • Carry a water bottle when you are going out.
  • Have water by you when you are exercising.

One client of mine lined up the glasses she needed to have before lunch and then did it again after lunch!

drinking water by glasses

Just increase it gradually as it’s not easy to start with, but you will get used to it and so does your bladder! Eating your 5 portions of veg each day also helps your body stay hydrated as water is also contained in fruit and vegetables. You can take a look at my recipes to find salads that help as well.

Why should I drink more water?

The simple truth is that dehydration can cause disease. We all know that water is good for the body yet we seem not to realise how essential it is for our wellbeing. If we begin to get dehydrated our body starts rationing the supply of water to certain parts of the body, when the level gets reduced further it begins to cause a reduction in normal function.

How does our body tell us this is happening?

Here are just a few signs that your body may be dehydrated:


Instead of reaching for the pills, reach for the water and drink a glass every 15 minutes until your headache goes. Most headaches are caused by dehydration, even migraines. When the body is dehydrated the brain can shrink temporarily from lack of fluid. This cause the brain to pull away from the skull resulting in pain and causing headaches!


The slow movement of faeces caused by dehydration allows colonisation of detrimental bacteria, yeast and fungi in our gut known as dysbiosis. Dysbiosis of the gut bacteria communities can cause many chronic diseases, such as inflammatory bowel disease, obesity, cancer, and autism.

Back and joint pain

It is important to understand that all our joints are dependent on water, particularly our spine. Water is a lubricant to allow the surfaces to move over each other when we mobilise a joint. The water also bears the force of the pressure exerted when the joint is in use. When you are dehydrated the joint takes more pressure and there is friction between the surfaces. So if you have back ache or your body is aching reach for the water.

High blood pressure

Did you know that when you are dehydrated your heart has to work harder to keep up the required blood flow? This is because the blood becomes thicker and the vessel walls tighten both of which contribute to heart disease.

Indigestion/heartburn/stomach aches

At a certain point of dehydration, nothing else will solve the problem other than water, no medication can rehydrate the body. Digestion depends on water being in plentiful supply. You can stop even the most severe digestive pain by drinking water according to Dr Batmanghelidj. One glass every 15 minutes until the pain subsides!

It is important for all of us to recognise pain as the body’s desire for water. Ignore it and you are more likely to develop problems later on: acknowledge it, take action and stay well for longer!

Instead of reaching for the pills drink more water. It may take some time to rehydrate your body, days or even weeks if your dehydration is severe.

Get in touch if you’d like more support either on a 1:1 basis or perhaps as part of my Healthy Habits Club community.