You have probably heard all about the term “staying hydrated” and been told a million times that you “should drink more water”. But how much do you actually know about the importance of staying hydrated?

This article will discuss the importance of hydration, what you can do to avoid dehydration and what puts you at risk.

 

What is dehydration and why is it important?

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When you hear the term dehydration, people are often referring to what doctors call hypovolaemia or “volume depletion”. Simply put, the reduction in the volume of water in blood vessels. However, dehydration is actually quite different to this as it is the loss of water from both the blood cells and the body’s cells.

 

Why is hydration so important??

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Because it is a vital component of regulating normal body function (Maintaining Homeostasis). Ensuring we have enough water means we can maintain our body temperature and lubricate our joints (*reaches for water bottle as my knee squeaks*). Additionally, our bodily systems including respiratory, neurological, circulatory and gastrointestinal systems also require hydration to function adequately.

If you suffer from a severe case of hypovolaemia, you could succumb to shock and collapse! ENOUGH SAID!

 

Benefits of having enough water:

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• Improves physical performance

  • When you exercise, you lose water through sweat so stay hydrated before, during and after exercise (replace 150% of water you lost through sweat!). Proper hydration can prevent fatigue, lower your heart rate and improve endurance.

• Helps aid weight loss

  • Research shows that people lose more weight when combining both an appropriate diet and an increase water intake (Dennis, et al. (2010) & Stookey, Constant, Popkin, & Gardner (2008)). 5 states that those who drank 500ml of water before each meal (3 x per day for 12 weeks) lost approximately 2kg more than those who did not.

• Boosts your mood

  • Those who drink more water tend to have better moods and feel better. Research found that those who increased their water intake from less than 1.2L per day to 2.5L per day suffered from less confusion, fatigue and sleepiness. However, those that restricted their water intake from their usual 2-4L per day suffered from a decreased calmness and had less positive emotions (Pross et al, 2014).

• Prevents headaches

  • In most cases, simply rehydrating can provide relief from a headache. Staying hydrated can also assist in prevention of some migraines for those who suffer from them often.

• Boosts brain power and prevents fatigue

  • More water in your system enhances your cognitive function with previous research showing that those who drink more water perform much better at tasks than those who do not (Riebl & Davy, 2013; Edmonds & Burford, 2009 & Edmonds et al, 2013).

• Protects against disease

  • Staying hydrated can assist in the prevention of asthma, urinary tract infections, coronary heart disease, kidney stones and potentially even some cancers.

 

So, just how much water do you need?

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A 70kg person for example, will be made up of 40kg (40L) water. Two-thirds of this water will be inside the cells (intracellular), one-third will be outside the cells (extracellular). This is just to give you an idea…you are essentially made up of over 50% water! Are you reaching for that drink bottle yet?!

How much you should actually consume each day depends on a variety of factors including gender, age, activity level and job. However, the general consensus is that women should aim for 2.2L per day and males 3L per day. If you participate in physical activity or labour, this will increase to also include 150% of the water you lost during the activity (eg. 1kg of body mass = 1.5L of water to replenish).

 

What are the signs and symptoms of dehydration?

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Often people think that if they are not thirsty, they are hydrated. However, what you may not realise is that when you are thirsty, it is too late. You are already dehydrated. Other signs and symptoms of dehydration include:

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• Dizziness, particularly when standing due to low blood pressure (which is a consequence of volume loss)

• Thirst, including a dry mouth

• Confusion (in severe cases as a consequence of inadequate oxygenation of the brain)

• An increased heart rate (as the body attempts to maintain blood pressure)

• Reduced weight (a 1L loss of fluid leads to 1kg of body mass)

• Skin taking longer to bounce back when pinched (known as skin turgor)

• Darker urine and/or less frequent urination (check out the urination chart à)

• Headaches

• Dry/cracked lips

• Feelings of nauseous, weakness and lethargic
  
  In severe cases, blood testing will often reveal that the kidneys have become impaired.

This is due to the kidneys requiring a large blood flow to function normally.

Essentially, with volume depletion comes a reduction in blood pressure which means blood
flow to the kidneys is compromised. They can then go into a state of shock.
This however, can be reversed when volume and blood pressure is restored.

 

 

Who is most at risk?

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Although we are all at risk of becoming dehydrated given the right (or wrong!)
circumstances, there are some populations who are more susceptible:

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• Babies- they are not able to tell you when they are thirsty! They also have a higher
  metabolic rate than adults meaning they require more fluid

• The elderly- our total body water reduces as we age and often, the elderly will have a reduced
  sensation of thirst. Additionally, many older people have kidney related diseases such as chronic
  kidney disease which impacts the ability to concentrate urine when volume is depleted

• People losing large volumes of fluid from the bowel such as through diarrhoea or colostomy

• People with impaired thirst mechanisms such as those with certain brain injuries or the elderly

• People taking medications that promote a loss of water such as diuretics (often referred to as water tablets)

 

Why do these people need to be extra careful?

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These vulnerable groups need to be aware of the increase risk of volume depletion and aim to minimise their risk by recognising the warning signs early on, maintaining fluid levels and seeking prompt medical treatment should it be needed.

 

I know I am suffering from volume depletion…what should I do now?

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At home, start with water if you are thirsty. Once you start to experience dizziness, significant volume loss has occurred. NOW is the time to take a trip to the doctor. If you have confusion, emergency treatment is required.

 

Dehydration in diabetics

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As dehydration can occur with prolonged high blood sugar levels, such as those often occurring in someone with diabetes, it is especially important for diabetics to monitor their blood sugar levels often. When a diabetic has high blood sugar levels, the blood will pull water from the cells of the body in an attempt to lower the levels. High sugar levels also make you pass more urine. Water is then pulled from bot intracellular and extracellular compartments, and thus the person is more prone to dehydration.

 

Can I drink Sports Drinks to rehydrate?

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In short, yes, However, in most instances, water (which has zero kilojoules) is the best option for hydration. Sports drinks do have their place in replacing electrolytes to assist in fluid absorption and carbohydrates and they are good in warmer climates (not to mention they often taste better!). But first and foremost, reach for the water!

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The bottom line…

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Water is VITAL for adequate functioning of the body. Although volume depletion can occur at any point during the year, it is important to be extra vigilant living in hotter climates such as in Queensland and during the summer months.

 

The key is PREVENTION and knowing the signs and symptoms.

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• Keep your fluids up

• Talk to your doctor regarding your medications and whether they are diuretics

• Keep an eye on friends, family and neighbours (particularly if they are elderly, babies or diabetics)

• Be Sun Smart!

• WATER IS KING! Consume before other types of drinks including sports drinks (unless instructed by medical advice)

 

References
 

1. Dennis, E.A., et al. (2010). Water consumption increases weight loss during a hypocaloric diet intervention in middle aged and older adults. Obesity 18(2): 300-307.

2. Stookey, J.D., Constant, F., Popkin, B.M. & Gardner, C.D. (2008). Drinking water is associated with weight loss in overweight dieting women independent of diet and activity. Obesity 16(11): 2481-2488.

3. Pross, N., et al. (2014). Effects of changes in water intake on mood of high and low drinkers. PLoS One 11(9): doi: 10.1371/journal.pone.0094754.

4. Riebl, S.K. & Davy, B.M. (2013). The hydration equation: update on water balance and cognitive performance. ACSMs Health and Fitness Journal 17(6), 21-28.

5. Edmonds, C.J. & Burford, D. (2009). Should children drink more water?: the effects of drinking water on cognition in children. Appetite 52(3), 776-779.

6. Edmonds, C.J., et al. (2013). Water consumption, not expectancies about water consumption, affects cognitive performance in adults. Appetite 60(1), 148-153.