Tuesday, February 21, 2012

Overhydration Leading To Hyponatremia

My previous write up on abnormal heartbeat and how we all should be careful with personal health resulted in this article about the other side of hydration - the excessive type.
Overhydration or known as water poisoning can happen when an individual consumed too much water that it upset the electrolyte balance in the body, usually leading to Hyponatremia. To better understand how this happen, we have to understand what are hypertonic, isotonic and hypotonic.
Osmosis is a process where liquid passes through a semi-permeable membrane (in this case, cell) where it moves from low solute to high solute concentration. This typically go against the typical notion that higher concentration will moves to lower concentration like when we spill water (from wet to dry area).
In the case of hypertonic solution where the concentration is higher outside the cell, water will be drawn out from the cell and the cell will shrunk - or become flaccid. This is typical as observed back in school science experiment when we immerse a potato into a salt solution and the potato will shrink (as water are being drawn out via osmosis). SO, taking too much salt during your sports too, will be demerital and will cause dehydration!
Isotonic is no stranger to sports people when they are essentially talking about the sport drink they consume. By mean of isotonic, it meant that the concentration inside and outside the cell is at equilibirum or steady-state. However, this has to be taken with a pinch of salt (no pun intended, since we are talking about salty solution here) as excessive salt intake will leads to hypertonic condition. The best isotonic drink in my opinion is still coconut water. Carbonated sports drink does more damage to you than good. Stay away if you can.
YOU DO NOT NEED ISOTONIC drinks if you exercise less than 2hours. The food intake of average Malaysian already has more than sufficient sodium to supplement a typical Joe that exercises. For example, a pack of Maggi Mee noodle has sufficient sodium to last you a week of running. Two slices of commercially available bread will gives you close to 200mg of sodium. So, the need for isotonic drinks should be limited if you are doing anything beyond 2hours.
Next is hypotonic condition where the solute concentration outside the cell is lower than inside. This will cause the movement of liquid into the cell, engorging/enlarging it before bursting the cell. This will happen when one drink too much water, upsetting the sodium and electrolyte balance in the body and causes the Hypoatremia problem, which could potentially lead to death.
Doing some research into Hypoatremia or condition sets by over drinking of water, i can't help but to even mistaken them for dehydration.
When you are going through Hyponatremia, you will feel:
  • Headache
  • Confuse
  • Irritable
  • Drowsy
  • Difficulty in breathing
  • Muscle weakness/jelly like feel
  • Twitching
  • Cramping (bet most of us think it's not enough salt!)
  • Nauseated
  • Feeling to vomit
  • Thrist (wow! from over drinking???)
  • Changes in behaviour
The above is easily misunderstood with being in a dehydrated state. It takes a trained medical personnel (and not St. John Ambulance personnel or unqualified medical personnel) to identify them to administer sodium solution or saline solution. 
Being an amateur competitive triathlete and having known my own limits and has guided many that knows me to recognize theirs (i hope i am not sounding too arrogant), it is safe to say that if you are doing endurance sports like i do, always learn to take a sip of water every 10 minutes if you are doing long endurance bike or run (i.e. anything in excess of 2hours) and supplement it with proper sports drink/mix like Accelerade or those energy drinks. I personally take Accelerade simply because it has a 1:4 protein to carbo mix. I take Endurolytes salt tablets from Hammer Nutrition as well to supplement if i am doing anything beyond 20km of run.

Staying alive during and after a competitive race sometimes just require a bit of common sense and moderate approach. Now that you know it is possible to die from over drinking, go easy in your next race - there is really really no need to gulp down those water at every water station and you have absolutely no reason to skip them too. Carry a bottle of fluid (energy drink would be good, as most water station gives water only) so you can take a sip after every water station you stop for a short drink.
Learn to recognise the symptoms above and learn to manage them should it happen to you, or someone near you in the future race.