Why Do You Need to Hydrate When Scuba Diving?

Last Updated: July 18, 2023

Do you go scuba diving every season? If yes, this is the right spot to learn how important it is to remain hydrated before, during, and after scuba diving.

While you are in deep waters during scuba adventures, you let your body evolve in the underwater environment where you discover a new mysterious world. But it’s essential to remember that water is an important part both externally and internally.

This article covers everything you should know about keeping your body hydrated and the consequences of dehydration. Let’s dive in!

What is Dehydration

staying hydrated while scuba diving

Dehydration is the condition that occurs when our body loses water. The body can lose water in several ways. It can be through sweating, urine, stool, and many other possibilities.

One of the fool-proof ways to know if you’re dehydrated is to check your urine color. Pale urine is the sign of good hydration, while the darker color of urine means dehydration.

A diver meets their crowing point when they find themselves dehydrated amidst billions of liters of water.

Does Scuba Diving Make You Dehydrated?

You already know how dehydration occurs. You lose sufficient levels of water in your body when you suffer from dehydration.

There’s this misconception that if you’re sweating too much then your body gets dehydrated. Reality check! You don’t sweat when you’re into deep waters. Then, how does your body sometimes dehydrate quicker than usual? Did that ever occur to you?

The reason is pretty straightforward when you know the basics of hydration, and dehydration. Hydration does not only come from water consumption. It is a balance of water and electrolytes in your body.

So the short answer is yes, scuba diving does make you dehydrated.

How Does Scuba Diving Dehydrate Your Body

Let’s have a detailed look into the various ways how your body might lose water while scuba diving.


The most common way of letting out water from the body is by sweating. But when you’re in your wetsuit, how often do you realize if you’re sweating or not? Just so you know, even if you’re not roasting and showing any signs of sweat outside your wetsuit, it’s guaranteed that you’re sweating underneath.

It is because the wetsuits don’t allow the body enough access to cool it down by evaporation. In the meantime, the body keeps trying to cool itself down, only to fail harder beneath your wetsuit.

The longer you keep your wetsuit on while outside water, the more chances you have of losing the water and electrolytes in your body through sweat.

That is why you should not wear your wetsuit until you’re about to get into the water. It would keep your body from dehydrating.


Dehydration through breathing is also possible, more so, for scuba divers. When you’re not a scuba diver, you dehydrate while exhaling, and you can prove that by breathing onto a glass piece. The resulting condensation is the water your body loses.

But there’s something special about dehydration through breathing when it comes to scuba divers. What is it, you ask?

We humans often forget the fact that the lungs humidify and warm up the air inhaled by us. The drier that inhaled air is, the more pressure is exerted upon the lungs to breathe in that dry air. Compressed air is dry air.

As for divers, their lungs go through double that effort to warm the dry air while under cold diving conditions. The compressed air tank that scuba divers gear up while diving into deep water lets them breathe with pressure on their lungs without even realizing it. That is how the body loses water, causing dehydration.

Therefore, you can dive with a rebreather to keep the air warm and moister.


If you are someone who prefers diving on a hot, warm, and sunny day, but rarely do you go out in the sun, chances are you’re exposing your body to sunburn.

When you’re getting sunburned, your body senses the heat and sends fluid to the skin. The sun, then, evaporates the fluid in the skin out of the body.

Keeping yourself on the safe side, apply a reef safe sunscreen on your body and keep it covered.


When you’re scuba diving, and you’re on a boat in the middle of the ocean, the wind is something of a fighter. Riding a boat involves going with the wind and also the ocean.

The wind evaporates the sweat, which leads to dehydration in the body. There is nothing much you can do to prevent this but to keep yourself hydrated. I’ll get into it later!


Chances are, the water you’re diving in is saltwater. While you’re on the boat, the saltwater already mists on your skin, and the next thing you know, you are deep down in that saltwater.

Later, when you’re done, the salt remains on your skin even after you’re out from the water. But the sun and the wind take away the water through evaporation, leaving the salt behind. The salt takes away moisture from your skin. Rinse it off with fresh water if possible.

Immersion Diuresis

You may have thought that you are well hydrated because of the frequent pee visits. But the reality is different. The blood runs from your limbs to your core when you are into cold waters that increase the blood pressure, flushing fluids. Also, the water pressure increases the blood pressure.

These two factors are highly influential for scuba divers to tend to pee a lot than usual (hence the term “peeing in your wetsuit”). Often, this ends up contributing to dehydration of the body.


Whether it’s because of heavy partying or seasickness, vomiting drains the fluids out of your body, leading to dehydration. Thus, you should try to keep yourself hydrated and drink fluids in between dives.


If you are on a vacation and you need to go diving, try to minimize alcohol consumption. Too much alcohol can deteriorate your health, leading to vomiting and hangover, which drains the fluids out, dehydrating you entirely.

Moreover, alcohol is a diuretic, which makes you want to pee more. Plus, alcohol has a lot of sugar content in it that needs to be diluted in water. A good rule of thumb would be to drink as much water for every alcoholic drink you’ve consumed. Try it out!

Do You Need to Drink Water Before Diving?

Yes, you need to hydrate yourself properly before diving. Why? Because dehydration can lead to divers suffering from decompression sickness (DCS).

Dehydration thickens your blood, which makes the flow of nutrients and gas exchange utterly difficult. The lack of gas exchange increases the risk of decompression sickness among scuba divers. It also leads to inadequate off-gassing of nitrogen.

Drinking water before diving keeps your body hydrated enough to go for a round of diving without thirst.

Not only water, but you can also drink electrolytes and similar fluids that keep you safe from dehydration.

Symptoms of Dehydration

Several symptoms indicate that your body is dehydrated, such as:

  • Little to no peeing
  • The darker color of your urine
  • Headache
  • You remain thirsty very often
  • Feeling tired or sleepy
  • Confusion
  • Feeling lightheaded or nausea

You should not wait for these symptoms to pop up. Instead, hydrate yourself regularly. But you should also remember that without even relaxing or noticing these symptoms you may already get dehydrated. So, drink water, some more water, and then some more – but not too much!

Tips to Avoid Dehydration During Scuba Diving

Here are a few quick tips to help yourself not to get dehydrated while you’re scuba diving:

  • Minimize or avoid diuretics
  • Cover yourself up
  • Try to prevent sickness and replace fluids and electrolytes if vomiting occurs
  • Drink fluids before you dive into the ocean
  • Fruits would make great pre-dive and post-dive snacks because they contain water, fructose, and many vitamins
  • While gearing yourself up with your equipment, try to stay under a shade
  • Wear off your wetsuit until you get into the water
  • Rinse the salt off your skin with clean water once you are out of the water

Final Thoughts

Dehydration is a common phenomenon experienced by people doing any kind of physical activity. Most people don’t even realise that they are suffering from dehydration. But, being a scuba diver triggers the importance of keeping yourself hydrated.

Going through dehydration not only disrupts your diving experience but also greatly impacts your health. Even a 2% body mass loss caused by dehydration reduces 10% of your physical performance. Dehydration in scuba divers is prone to cause decompression sickness.

You should drink enough water before and after a dive. Drinking water is, in fact, one of the must-dos before and after a scuba diving bout.

Whether you’re a scuba diver or not, you still should drink lots and lots of liquids. Go ahead, and stay hydrated.

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