Healthy Hydration for Scuba Divers

diving hydration

When surrounded by water scuba diving, taking in hydrating fluids may not be top of mind.  Diving, in addition to the topside motion of being on the water out in the sunshine, is dehydrating. Taking in fluids is not just a good practice, it’s essential for healthy scuba diving.

To learn the best ways to stay hydrated, we’ll first explore the sneaky ways divers lose water and how it affects dive performance. Good news? Our easy tips to avoid dehydration.  

How  Dehydration Happens

Dehydration occurs when more water and fluids leave the body than enter it. Since the human body is mostly water- roughly 75 percent- losing even low levels can cause uncomfortable symptoms like headaches and lethargy. Sustained dehydration could also pose serious health risks.

Usually people associate fluid loss with sweating- like during a heavy workout or exercising in the sun. But those things don’t happen all that often while scuba diving, so why do divers dehydrate quicker than normal? There are some factors you may not have even thought of before.

  1. Respiration. Just by breathing, we lose some hydration. Our lungs continuously work to humidify and warm up the air we breathe, and during the dive, that air is extremely dry, compared to the topside atmosphere. Have you ever noticed a dry mouth or throat during or after diving? Dive tanks filled with compressed air- designed purposely dry to remove almost all moisture, keeping corrosion out of the tank. As a consequence of breathing such dry air, only about half of the normal moisture is exhaled.
  2. Immersion Diuresis. This technical term for “peeing in our wetsuit” could be a whole post in itself because it should be avoided for several reasons, but an important one is hydration. Jumping into water that is colder than the air causes a narrowing of blood vessels in our arms and legs, forcing more fluids back towards our torso. The body reacts to this increase of blood pressure around core organs by attempting to flush fluids from the body. Just remember that frequent urge to pee while diving also means fluid loss, and the sensation will pass as your body adjusts to the change in temperature.
  3. Sweating. Maui is a warm, humid climate with plenty of sun exposure which causes perspiration. The boat in motion may keep you cool, but if you put on your wetsuit too early before the dive, you may start sweating and prevent the evaporative cooling of air on your skin.
  4. Vomiting. We all love those perfect glassy-water days, but rough seas do happen, especially on some of our more challenging adventures. It is estimated that roughly 1 in 3 people suffer from motion sickness. Vomiting is another demon of dehydration that also causes an electrolyte imbalance. If you feel there is a risk of sea-sickness, best to take a remedy containing Dimenhydrinate at least an hour before leaving the dock.

The Effects of Dehydration on Divers

So far, we have been talking about pretty mild symptoms of dehydration. However, a more serious consequence is adding to decompression sickness.

When the body is dehydrated, blood flow is slowed reducing the speed at which we eliminate absorbed nitrogen. Even when staying within dive table limits, a dehydrated diver is at greater risk of decompression sickness.

Dehydration can cause a number of other symptoms, potentially reducing diver safety, including:

  • muscle cramping and fatigue;
  • increased heart rate and blood pressure; 
  • headache;
  • weakness and exhaustion;
  • reduced awareness;
  • sleepiness;
  • confusion.  

Tips for Proper Hydration

Although dehydration can cause mild to serious conditions, avoiding it is quite simple.

Be well hydrated before diving. The time to start hydrating is before you even get to the dive shop. Starting the day before, limit alcohol intake. Alcohol is dehydrating and the effects can last into the next day.

On the day of your dive, drink small amounts of water at regular intervals throughout the day. Don’t wait until you are thirsty, as this is a symptom you are already starting to get dehydrated.

What to drink. Water is your best hydration option. It’s okay to flavor water with enhancer drops, a bit of fruit juice of a lemon wedge, but avoid too much coffee or other drinks with caffeine, as these have a mild diuretic effect. A re-usable BPA-free water bottle with measurement markings will help you track your water consumption.

What to eat. Fruit, which contains vitamins and fructose, and mineral-rich foods like bananas and mushrooms are great examples of foods to add to your hydration efforts before and after diving.

Take care during your dive. On the boat, utilize shade and cover up to avoid overheating and excessive sweating.In addition to avoiding peeing in your wetsuit, don’t forget to take a few sips of water during your surface interval.If you are prone to seasickness, tuck some oral rehydration salts or an electrolyte drink in your dry bag.