Did you know that divers are almost always dehydrated during and after a dive? Dehydration occurs when the body loses more fluids than it takes in; even a 2% loss of water in the body can result in up to a 10% reduction in physical performance effecting the body’s ability to off-gas, and increasing the chances of DCS (Decompression Sickness).
How do we become dehydrated during scuba diving activities?
Alcohol – Let’s be honest, most of us dive when on holiday, and for most of us this includes some holiday cheer in the form of the occasional sun-downer cocktail, ice cold beer or other alcoholic beverage. Alcohol is a diuretic, increasing our need to urinate and therefore expel water and electrolytes. A hangover is our body’s reaction to dehydration in this instance, and really needs to be avoided if you are diving the next morning (and not just because it will make you fell seasick)! It is worth noting that caffeine is also a diuretic, and especially on those early morning dive trips a lot of will reach for a coffee or tea to kickstart the day.
Vomiting – Whatever the cause, be it seasickness, food poisoning etc., not only is it uncomfortable, it can leave the body in a severely dehydrated state along with a severe electrolyte imbalance.
Climate/Sun -Many of the best dive locations and reefs are located around the tropics meaning plenty of sunlight and sun exposure. Any type of sunburn leaves the skin red, hot, and painful, and initiates the body’s natural defence mechanism of rushing fluid to the skin which then evaporates in the heat leading to fluid loss.
This heat also leads to increased sweating and the possibility of overheating. Putting on a wetsuit has never been the easiest activity in the world! Add to this the heavy equipment as we gear up, and sweat dripping down a diver’s face is a pretty common sight just before jumping in to dive.
Wind/breeze – The cooling breeze that we enjoy during the boat ride tot he dive sites also works to remove surface moisture and sweat from exposed skin.
Salt – There’s no avoiding this one! Divers have direct contact with salt on their skin before, during, and after their dives. Before the dive we are likely to be blown with salty breezes or spray during our journey and when the boat hits waves. This salt on our skin draws water away from the skin tissue, where it quickly evaporates. When we dive we are immersed in salt water and when we return to the surface, unless we rinse off thoroughly with fresh water, there will be salt water on our skin which evaporates leaving small salt crystals on our skin and hair.
Breathing – Again no getting away from this! We naturally lose water through exhalation. I’m sure all of you a some point will have noticed how if you exhale on a mirror it fogs up under your breath and there is a residue of moisture left on the face of the glass. As we breathe air into our lungs, moisture moves from the body into the air to saturate it. The dry, filtered compressed air from a Scuba Tank requires nearly twice as much moisture to saturate it than breathing regular air from the atmosphere.
Mild to moderate dehydration in divers can lead to the following:
- Weakness and exhaustion
- Headaches – usually a sign of dehydration due to insufficient fluids in the blood vessels of the neck and head.
- Poor air consumption
- Reduced awareness
- Increased risk of decompression sickness
Dehydration compromises our circulatory system. Its ability to transport nutrients and blood gases such as oxygen, carbon dioxide and nitrogen diminish. The reduction in water increases the viscosity (thickness) of our blood reducing blood flow and the circulating blood volume. As the circulatory system is vital to the off-gassing of inert gas such as nitrogen, nitrogen release may be compromised in a dehydrated diver leading to an increased risk of developing DCS.
To make matters worse, the signs and symptoms of dehydration are easily be confused with the signs and symptoms DCS!
- Avoid diuretics, especially alcohol.
- Cover up.
- Do your best to prevent sea sickness, but if vomiting occurs remember to replace fluids and electrolytes as soon as possible.
- Hydrate before your dive
- Fruit contains water, fructose and vitamins and is great both pre-dive and post-dive. (You’ll find plenty on our dive boat the Reef Ranger)
- Utilize shade as much as possible, especially for equipment set-up.
- Remain out of wetsuits until ready to get in the water.
- Rinse the salt off your skin soon after diving.