Do you really understand dehydration?

Do you really understand dehydration?

Rob Hobson dispels the myths and advises on how to stay hydrated

Registered nutritionist and Head of Nutrition at Healthspan, Rob Hobson, explains about dehydration and provides his top tips to rehydrate and dispels some of the common myths about how to hydrate the body.

The importance of water

Water makes up around 50-60% of your body weight and is a major component of muscles and organs.  Water is required by the body to transport nutrients around in the blood, discard waste, digest food and reduce body temperature by sweating.  Glucose is stored in muscle tissue as glycogen and for every gram, it holds 3-4g of water.  This is the reason why low carb diets result in an initial rapid weight loss (water loss) and causes increased dehydration.

You can survive for some time without food but your chances of survival in the absence of water are less promising as all the cells, tissues and organs in the body require water to work properly.  Water constantly moves through cells with about 10% of your body water being replaced every day with a fresh supply.  Blood for example is about 93% water and muscle is around 73%, whereas fat is about 10%.

Water requirements

Recommending a water requirement is misleading as it is fluid and not just water per se that is important.  You can manage your fluid intake with both food and drinks.  How much fluid a person needs is dependent on the individual and their lifestyle or environment.  For example, someone who lives in a hot country or exercises a lot will require more fluids as their needs are greater due to sweating.  Pregnant women require more fluid in their diet due the increase volume of blood in their body and the effects of gastric bugs that cause vomiting and diarrhoea cause demand an increased fluid intake. 

Older people often experience the uncomfortable effects of dehydration such as constipation and this is also the leading cause of falls and fractures as dehydration can cause dizziness and disorientation.  As a rule, most consider 1.5-2L per day of fluids to be a benchmark for adequate hydration, but this can come from many types of fluid and foods in the diet.

Recognising dehydration

The problem with dehydration is that by the time you experience any noticeable signs you are already very dehydrated.  Symptoms such as headaches and fatigue are common when you’re dehydrated, but these are late signals as unfortunately the body is very good as hiding mild dehydration and it can take quite a few hours before you recognise what is going on.  If you are a keen sports person, then this could have quite an impact as you make not feel thirsty, but your body could be very dehydrated.  The most important strategy in all cases is to hydrate regularly.

6 key signs of dehydration

The most common signs that you are dehydrated can include:

  • Little or no urine or urine darker than usual
  • Dry mouth
  • Extreme fatigue, mood change and a lack of concentration
  • Headaches
  • Confusion
  • Dizziness

Whilst a healthy diet and exercise often take centre stage when it comes to health and wellness advice, hydration often gets overlooked but is just as important, but there are many myths and misconceptions surrounding the topic. These ten facts help to differentiate fact from fiction and offer a few useful tips to keep well hydrated.

Coffee doesn’t dehydrate you

Advice about hydration often recommends avoiding too much tea and coffee, which is based on the caffeine content of these drinks but contrary to popular belief, good quality research has shown in fact, coffee hydrates as well as water over a 24-hour period.  Whilst you may urinate sooner, you will not urinate more than you consume.  Army research on caffeine and dehydration confirms coffee is an acceptable source of fluids even for athletes, including those that exercise in the heat.

The eight-glass rule

There is no scientific evidence whatsoever to back up the advice to drink eight glasses of water each day and whilst it not a bad rule to follow, a better way to think about hydration is to drink enough so you go to the loo every two to four hours.

It’s not all about water!

The well-versed mantra of 1.5L of water per day is not incorrect but misleading and thinking that you will not be properly hydrated unless you drink this amount daily is simply not true.  Food as well as drinks can provide valuable fluid throughout the day.  All fruits and vegetables contain a good source of water especially foods such as melons and cucumbers.  Dairy foods count too, which includes milk and yoghurt.  Soups, stews and casseroles are also a good way to add fluids into the diet if you can’t face chugging back glasses of water.

Electrolytes do help with hydration

When you sweat, you lose water from inside and outside of your cells.  The water outside the cells is rich in sodium, an electrolyte that works in balance with potassium.  Potassium is an electrolyte inside the cells.  Sweat contains about seven times more sodium than potassium, hence sodium is the most important electrolyte to replace during extended exercise but potassium and magnesium count too.  Try Avtiv Hydrate+ from Healthspan 40 tablets £11.99, a fruit blast electrolyte sports drink.

Dehydration affects athletic performance 

Less than 5% dehydration doesn’t appear to make much difference to muscle strength or performance when working out in short bursts such as interval training or weight lifting.  However, distance runners can see a 2 percent reduction in pace for each percent of body weight lost through dehydration which can seriously hinder performance and a sweat loss of more than 10% body weight can be life threatening. 

Does water remove toxins and improve skin tone?  

This myth is commonly touted about but there is no conclusive evidence from the available research that excessive water intake will remove toxins from the body.  As far as skin is concerned, dehydration can leave skin looking less plump and one of the signs of dehydration is that after pinching the skin it may remain ‘tented’ and take time to return to its normal flat appearance.

Drinking water may help with weight loss

Drinking water or any other fluid before and after eating has been shown to help with weight loss and research has shown that people who drink more water as part of a weight loss programme lose more weight that those who do not.  This is simply down to the fact that filling the stomach with fluids reduces hunger before eating.

Try sprucing up your water with herbs and fruits

If you get bored of drinking plain water, then explore the many variations of fruits and vegetables that help to improve the flavour and interest.  Look to herbs such as rosemary, basil and mint as well as fruits including citrus, strawberries and vegetables such as cucumbers.

Try and drink on schedule

If you always forget to drink, then stick to a schedule.  Make sure you drink when you wake up and at every mealtime then before bed.  You could also train yourself to drink every hour, which is easy to do if you’re sat at your desk.

Hydration helps with digestion

Keeping well hydrated is important for digestive health and maintaining regular bowel movements but this is often overlooked by people suffering with constipation.  Dehydration can leave you feeling bloated and sluggish, which can impact on day-to-day life.  Advice around gut health recommends increasing your fibre intake but often this advice fails to note that you need to also increase your fluid intake to help fibre to swell and do its job and help food to pass more easily through the gut.  

Hydration is usually overlooked when it comes to health and wellness advice but is just as important as a well-balanced diet and regular exercise.  Being mindful of your fluid intake will help you to maintain optimum health, whilst insuring good digestion and energy levels.