The Importance of staying hydrated while scuba diving

There are many factors that can contribute to dehydration in scuba divers

We think of running, cycling and triathlons as physical activities where hydration is absolutely critical.  But scuba diving does not seem to have that same critical need, so hydration tends to be downplayed by scuba divers, reduced to just a “good practice” when going diving.  Think again! Here are  several tips for effectively keeping properly hydrated for your dives.

First of all, here are a few symptoms of dehydration you should be aware of:

  • Little or no urine, or urine that is darker than usual
  • Dry mouth
  • Headache
  • Extreme thirst
  • Sleepiness or fatigue
  • Confusion
  • Feeling dizzy or lightheaded

Take a look at some of the well-known and not-so-known factors that reduce hydration levels when Scuba Diving:

Sweating (climate) – Diving often takes us to tropical locations with the greatest abundance of coral reefs, as they are near the equator with good sun coverage and warm waters.  With the lower latitudes comes warm, humid, tropical climates that increase sweating.  But even in the northern latitudes, divers may sweat just carrying gear bags and tanks, and suiting up for their dive.  Sometimes tourists come to the tropics for their once-a-year dive vacation and they are not at all accustomed to the  humidity and do not do such a good job staying hydrated!

Sweating (exposure suit) – Also, no matter the latitude, divers wearing wetsuits will sweat under every square inch of that neoprene.  So when we see a diver wearing a wetsuit or drysuit and he has a few lines of sweat running down his face, don’t be fooled.  Underneath that exposure suit he is sweating more than the exposed skin where air is evaporating sweat and cooling the skin.  A steady increase of body temperature takes place the longer the exposure suit is worn out of the water.  Sweating underneath the exposure suit can be profuse, but it is hidden, making it quite deceptive.

Respiration – Our bodies naturally loose water through exhalation.  You can notice this just exhaling on glass and seeing your exhaled water vapor create a fog on that glass.  But when scuba diving, water loss through respiration is increased significantly due to our breathing of highly filtered and very dry compressed air.  This air, with virtually no humidity, draws even more water out of the body during respiration.

Sun – Our best dive locations have excellent sunlight.  As we engage in this outdoor activity we are susceptible to large amounts of sun exposure.  A mild to moderate sunburn leaves the skin red, hot, and painful.  Just as with any other skin burn the body rushes fluid to the skin.  Being outdoors air will evaporate the moisture on the skin, leading to further fluid loss.

Wind – Because scuba diving is an outdoor activity another natural factor contributing to dehydration is wind.  Not only do the tropics have healthy breezes, but a swift boat ride to a dive site can remove surface moisture and sweat from exposed skin.  The faster the wind, the higher the rate of evaporation.

Salt – The majority of scuba diving takes place in salt water.  So divers have contact with salt directly on their skin before, during, and after their dives.  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.  Before or after the dive we may be blown with salty ocean breezes or even salt spray when the boat hits waves.  Since salt 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.

Vomiting – If you’ve spent time on a dive boat, you understand the plight of those who are plagued with sea sickness.  Not only is it embarrassing and uncomfortable, but vomiting can leave the body in a severely dehydrated state along with a severe electrolyte imbalance.  The more one vomits, the greater the chance of severe dehydration.

Diarrhea  -  Choosing exotic locations to dive at may also come with an exotic choice of foods, choose where you eat, Diarrhea or "Bali Belly" as we like to call it,  can lead to severe dehydration without having to many of the above mentioned symptoms, so if you do experience a touch of "Bali belly" its very important to make sure you are hydrating yourself correctly!  

Alcohol – Dive trips are often fun, tropical vacations.  It is important to recognize that drinking alcohol is quite common during dive vacations.  Alcohol consumption actually counters water consumption since it is a diuretic.  Alcohol diuresis is increased urine output resulting from the consumption of alcohol.  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. Its very easy to sneak a few beers in over lunch, but remember no Alcohol before diving!


Here are some tips on staying properly hydrated when scuba diving, plus links to items I actually use:

  • Hydrate early, at regular intervals, hours before your dive.

  • Carry a re-usable, water bottle

  • Hydrate during surface interval times

  • Remember, fruit contains water, fructose and vitamins and is great both pre-dive and post-dive.

  • Utilize shade as much as possible, especially for equipment set-up.

  • Remain out of exposure suits until absolutely ready to get in the water.

  • Apply sunscreen liberally and every one hour of sun exposure.  Waterproof sunscreen is not waterproof.  Being underwater, rinsing off, and sweating gradually removes sunscreen.  Use SPF 30 or higher (We recommend higher).

  • Cover up.  

  • Rinse the salt off your skin soon after diving.

  • Do your best preventing sea sickness.  Look into medication or using your sea legs.  (Lucky we have a very flat ocean around the Gili's so this is not normally a problem)

  • If vomiting occurs remember to replace fluids and electrolytes soon thereafter. Drink coconuts!

  • Avoid alcohol.

  • Plain water and sport drinks: GOOD Energy drinks:  BAD

Our Motto here at Blue Marine Dive is SAFETY FIRST, for every dive you do, add a bottle of water to your daily intake!


Info: Nicholas Manning &


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