It’s no secret that our bodies depend on water for survival. In fact, it could be said that half our body weight is water. Every cell in our bodies depends on water to function properly. As a general rule, men need around 3 to 4 litres of water per day while women need slightly less. So what’s this got to do with water sports?
We lose water through sweating and evaporation of that sweat accelerated by a sea breeze or the greater flow of air felt during a fast motorboat ride. Sweating underneath an exposure suit can be profuse but because it might not be noticed its effects can be insidious.
Naturally, our bodies lose a lot of water simply through respiration. You can see the water vapour on your breath on a cold winter’s morning, but the water is there even when you cannot see it precipitating as vapour.
We tend to enjoy water sports most where the weather is warm and sunny. Getting sun burnt can cause the body to rush fluid to the site of any irritation so reddened skin will mean you need to imbibe more water than otherwise.
Most of our activities, be it sailing, surfing, water skiing or scuba diving, take place in seawater. Sea spray can leave a residue of salt water that turns to crystals as it dries. Since salt is hygroscopic it has the ability to attract and hold water molecules. When it sits on our skin it can pull water away from the skin tissue, where it quickly evaporates.
If you scuba dive you are particularly susceptible to dehydration because you breathe air (or nitrox) that has been dried before it was pressurized to fill the scuba tank.
Then there’s immersion diuresis, the technical term for peeing while you are underwater. As we dive, ambient water pressure and the cooler temperature of water may both have a role in shunting blood from the extremities (arms and legs) into the thorax. When the body recognizes the increase of blood around core organs, and the subsequent increase in blood pressure, it attempts to flush fluids by increasing urine output. That is the reason for the frequent need to urinate during dives.
Hopefully, you don’t suffer from seasickness but if you do be aware that vomiting has a dramatic effect by leaving you severely dehydrated along with a severe electrolyte imbalance.
It is also very important to recognise that drinking alcoholic beverages, though quite common during dive vacations, can cause dehydration. Alcohol consumption actually counters water consumption since it is a diuretic. Alcohol diuresis results in increased urine output. The alcohol suppresses production of the body’s anti-diuretic hormone leaving the person with a frequent need to urinate, speeding up the loss of fluid from the body, and leading to dehydration.
Dehydration is especially important to avoid if you are scuba diving because it has been proved time and time again to have a link to decompression illness. Being dehydrated increased the possibility of a diver needing emergency treatment for the bends. Even if you are not a scuba diver, it can lead to discomfort and loss of performance leading to mistakes being made.
So how do you know if you are in danger of being dehydrated? You may produce reduced amounts of urine than normal and it may look darker than usual. A headache is a sure sign. Of course you might experience a severe thirst, with fatigue or even sleepiness. Feeling dizzy or light-headed is a warning sign as is confusion and the inability to concentrate.
As the blood thickens to reduced water content, the circulatory system becomes compromised. It’s ability to transport nutrients and blood gases such as oxygen, carbon dioxide and nitrogen diminish. This leads to muscle fatigue, cramping, high blood pressure, rapid heartbeat, confusion, and increased breathing.
Mild to moderate dehydration can lead to weakness and exhaustion, muscle cramps, poor air consumption (by a diver) reduced awareness and for a diver, an increased risk of decompression illness.
So hydrate early and at regular intervals, gauge your consumption by carrying a marked bottle. Eat plenty of fruit because not only does it contain water, it has fructose and vitamins too.
Use the shade as much as you can and wear your exposure suit only when you are ready to use it in earnest. Apply plenty of sunscreen and know that even waterproof sunscreen gets washed off. Rinse dried seawater off as soon as you can and wear a brimmed hat and a long-sleeved shirt.
Avoid diuretics like alcohol if you are going to scuba dive. Drink plenty of plain water!