How Dehydration Can Cause Common Illness


As an adult your body, on the whole, is made up of approximately 75% water, with your brain and lungs being more than 85%. The importance of being fully hydrated with water is usually accepted but less commonly understood as to why this is the case. The general understanding is that dehydration can cause the usual ailments such as dry mouth, headaches, constipation and lack of concentration to say the least, but in fact it can be the cause of many more physiological issues than that. It is understood that not having enough water over a long period of time could one day lead to more serious disease such as heart disease, stroke and even cancer.

Think of your body as a group of fully functioning systems rather than one body working as a whole. These include the cardiovascular, respiratory, digestive and muscular systems amongst many others. Each system has its own nerve supply, blood supply and of course water supply. For example, it is possible for one system to be flowing with blood whilst another is receiving minimal supply. This is necessary and a normal occurrence, for example when you ride a bike, blood flow will increase to the legs to increase oxygen supply to the muscles whilst the blood in your arms will reduce to accommodate this. If you eat a large meal it is recommended you do not exercise afterwards as this may inhibit digestion, simply because the blood will rush to your skeletal muscles rather than to your digestive system which is where it should be after eating. The body will always choose the system that needs the blood the most at one time and the other systems sacrifice for a short while. The same is for water.

It is agreed that water is essential for the functioning of every cell in our body, seen as each cell is mostly made up of water. A fully hydrated individual will have enough water to service the entire body giving cells their healthy rigid and plump forms. However an individual who is lacking in water can expect to have some systems of the body suffering the cost of this, with cells shrivelling like a raisin. The systems in which this will happen to first appears to be different for each individual based on the following information.

A theory brought about by Dr F Batmanghelidj is that common illnesses experienced by modern humans such as asthma, heart disease, gout, osteoporosis and even cancer may at times be caused by lack of water. For example if the respiratory system is dehydrated for a long period of time, the cells are not, and have not, been operating optimally leading to stress in this area and eventually a respiratory disorder such as asthma. Illness, allergies and disease are a result of stress which can be caused by a lack of water. If your digestive system is dehydrated over a long period of time, one of the side effects might be bowel cancer. The benefits of plenty of water in your daily diet lies not just with disease prevention but in the positive aesthetic effects. Skin is the largest organ in your body and if it is given plenty of water throughout the day you are likely to appear at your most youthful.

When we are dehydrated we may not feel thirsty but this does not mean the body does not need water. Lack of thirst is the bodies coping mechanism when dealing with ‘droughts’; to be plagued with constant thirst when water is not available would be unbearable. The same is similar to hunger, once the body decides there may not be any food for a while you may be hungry at first but then the feeling will eventually go away for a while to make the day much easier to bare.

How much shall you drink?

The good news is that water can be replenished quickly and can be gained from food sources such as fruit and vegetables, but it is best to drink additional water in the day to ensure you have had enough. To maintain its normal physiological functions the body will lose approximately 6 – 12 glasses per day so this amount must be supplemented. To be more accurate the recommendation is to consume 2-3 litres of water per day for a sedentary adult, the figure varies dependent upon the size of the person. This value increases if you exercise, usually an extra litre per hour of exercise (maybe more if you sweat a lot). You will also need to drink more if you sweat during the day for example if you live in a hot country. Other times when you will need to increase your water consumption is when you eat or drink any substance that will tend to draw water out of your cells such as sugar and salt. Most will know that after a salty meal you will be thirsty, but many might not know that sugar has the same effect. You may notice that after consuming a lot of carbs and sugary snacks and drinks in a short space of time you will experience extreme thirst afterwards. That is the diuretic effect of sugar.

Caffeine and alcohol act as diuretics. In fact it is believed that a hangover after a night out is due to a lack of water, and that if you consume enough water during the night and before bed, the effects of alcohol will not be felt as strongly the next day. The common ‘spinning’ sensation the morning after a heavy night out is a sign of severe dehydration.

Food and drinks that cause dehydration

  • Coffee
  • Caffeinated tea
  • Alcohol
  • Processed fruit juices and drinks
  • Fizzy drinks such as cola and lemonade
  • Salty foods both processed and home made
  • Cakes, biscuits, sweets and other sugary snacks

Reference: Batmanghelidj, F, Water & Salt. The Tagman Press, 2007


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