dehydration head pic


I knew water was important, it’s the sustainer of life and all that but I don’t think I always realize quite what an impact just a little dehydration can have on our bodies. Let’s talk about some important percentages to set the scene - your body is 70% water, your brain is 75 – 80% water and your blood is 95% water. Needless to say lack of water can have serious effects on your body’s normal operating mode. Dehydration and its symptoms start at just a 1% loss in your normal water volume and become noticeable after 2%. If you are a sportsman or women just a 2% loss in water can lead to a 30% drop in performance.

If you’re low on time those few facts should be enough to convince you to drink water or hydrating fluid of some type (no tequila doesn’t count, sorry guys). You should be taking in roughly 2 – 2.5 litres of fluid a day because that’s how much the average person will lose in the climate of the UK.

What is dehydration?  In general terms dehydration is when you lose more fluid than you take in. But there are three different sorts

  • Hypertonic – which is the loss of water
  • Hypotonic – the loss of electrolytes in particular sodium (you lose these when you sweat and it’s what gives you skin that salty texture and taste)
  • Isotonic – the equal loss of water and electrolytes and the most common type of dehydration in humans (sports drinks such as Lucozade are designed to help combat this)

+   Symptoms

1-2% Dehydration

  • Headaches
    • One of the most common and obvious symptoms of dehydration. Dehydration is also one of the most common causes for a headache
    • Dehydration tends to lead to a headache at the back of your head that gets worst when you bend forward
      • Why? The lack of water causes chemical imbalances in your blood which the brain is sensitive to and interprets as pain
    • Dehydration can also lead to decrease in blood volume which causes less blood and oxygen to get to your brain
  • Decrease in the amount you pee or really dark pee (check your pee (it’s not weird) regularly especially in hot weather or after doing physical activity it should be a pale straw colour if you are well hydrated, check out the pee colour chart)
  • Thirst and dry mouth
  • You may start to notice dizziness due to a drop in blood pressure
  • Lack of appetite
  • Tiredness and fatigue

3-6% Dehydration

  • Decrease in reaction time and concentration
  • Grogginess
  • Nausea/vomiting
  • Muscle cramps and joint pain
  • You may notice an increase in heart rate and breathing (sometimes difficult to notice if you’re running around)
  • Decrease in sweating and dry skin (your body is trying to stop the loss of anymore water but sweating is an important way to regulate body temperature so your body temperature will increase)
  • Increase in body temperature
  • Constipation

7-15% Dehydration

This is considered untreated extreme dehydration. You will require immediate emergency care.

  • Delirium
  • Unconsciousness

+   Causes

  • Anything that causes you to sweat a lot gives you an increased chance of getting dehydration especially if you are unable to drink enough water
    • Physical activity especially in the heat
    • Prolonged exposure to sun/heat
  • Getting ill, any illness that cause you to lose fluids such as:
    • Cold and flu
    • Diarrhea
    • Vomiting
    • Fever
  • Caffeine
    • Caffeine is a diuretic which basically means it will cause you to pee more and lose more fluid than normal
  • Alcohol
    • Also a diuretic
  • Dry air
    • Such as the recycled airplane air when flying
  • Burns, including sunburn
  • Altitude
    • This is partly why your hangover headache feels so much worst in the Alps, and you should be careful when drinking alcohol at high altitudes.
    •  Skiing is actually an ideal time to get dehydrated, you get a little sun burnt, you’re at altitude, you have a little too much to drink and its cold so you don’t feel the need to drink water. So be careful.
  • Certain drugs
    • Especially amphetamines
  • Malnutrition and fasting
  • Undiagnosed or unmanaged diabetes will often cause dehydration through increased urination

+   Preventing dehydration

  • Monitor frequency and colour of your pee, it’s a tell tell sign of dehydration
    • You should pee every 3-5hrs
    • It should be a very pale straw colour or even better colourless
  • If you are sweating a lot or ill remember you will need to replace electrolytes and salt as well as just water
    • Sports drinks like lucozade will help with this
    • Or make your own and add some fruit juice with a pinch of salt to your water
    • Be careful as fruit juice can make diarrhea worse, there are special diarrhea medications such as Dioralyte which have salts and sugars to help with rehydration
  • Eat food high in water content, such as soup fruit and vegetables (again fruit and vegetables can be difficult for your stomach to digest if you are sick or have diarrhea)

+   Treatment

  • For more severe dehydration you may require help from a medical professional  who may start you on an IV (a needle placed directly into a vein to quickly get fluids back into your blood)
  • Water, cool water is best for sports players
  • If you have diarrhea or vomiting there are over the counter electrolyte packets such as Dioralyte
    • You may struggle to keep up fluid intake with vomiting, anti-nausea medication may help. Or cola can help keep your stomach more settled, it shouldn’t be substituted for other fluid however due to its caffeine content can increase dehydration
    • Medicine like Imodium can help to reduce diarrhea
  • If your body temperature is particularly high try putting a damp cloth on your neck or head

+   References

  • Wikipedia
  • Mayoclinic
  • Zocdoc

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