When it comes to the risks associated with scuba diving, some, such as hypothermia, running out of air, and being separated from the boat seem apparent. One in particular is quite surprising though: dehydration. After all, how could someone who is surrounded by millions of gallons of water suffer from dehydration? Unfortunately, this risk is a real one; when we take in less fluid than we’re losing, even just through respiration and sweating, the body becomes dehydrated and is at a greater risk of malfunctioning.
What Causes Dehydration
When diving, the majority of the water your body loses exits as you exhale. In addition, the air you inhale from your cylinder is completely devoid of moisture, which is present in the atmospheric air we typically breathe; this means that the moisture lost by your lungs must be continually replenished by the body. If you are breathing rapidly or are diving for a long period of time, it is possible to become dehydrated very quickly.
The second way our bodies lose moisture while diving is via perspiration, particularly in areas where the water is warm and we’re exerting ourselves. It might seem strange that we’re capable of sweating underwater, but it does happen.
Finally, the risk of dehydration increases dramatically when we are not appropriately hydrated before diving. Many of us are in a constant state of mild dehydration due to inadequate water intake, excessive caffeine intake, and other factors.
Risks Associated with Dehydration
Dehydration poses serious risks to the human body – in fact, it can be fatal. Water helps our bodies function in many ways; we simply cannot live without it. Not only does it aid in numerous biochemical processes, ensuring that each of the body’s cells are well-balanced and functioning as necessary, it maintains the body’s electrolyte balance.
Dehydration can contribute to a higher risk of decompression sickness. Since our blood volume decreases when we are dehydrated, the body’s ability to absorb and release nitrogen is negatively impacted, and nitrogen levels can spike. Along with the increased risk of DCS comes some additional risks – those of paralysis and even death.
Finally, when our blood volume is low, the heart must work harder to ensure all the body’s tissues are supplied with oxygen and other nutrients. The stress on the heart contributes to fatigue, which in turn contributes to complete exhaustion and the inability to perform well under demanding physical conditions experienced during diving.
Signs of Dehydration
There are a number of ways to determine whether you are beginning to suffer from dehydration. Don’t ignore these symptoms if they occur, and try to avoid them in the first place – you’ll be better off.
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Thirst – This is one of the most common symptoms of dehydration. If you are experiencing thirst, you are probably dehydrated.
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Nausea – If you begin to feel nauseated while diving, you could be experiencing underwater seasickness; if you are not subject to motion sickness or if conditions do not warrant motion sickness, it is possible that you could be dehydrated.
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Dry or sticky mouth – When your body is low on water, it begins to pull water from auxiliary functions – such as saliva – to keep vital functions, such as consciousness, going. If your mouth feels dry and / or sticky, you are most likely dehydrated.
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Headache – Dehydration affects the biochemical functions of the body, and can contribute to a headache. In addition, when the blood vessels in the brain and neck are not carrying enough fluid, a headache can happen. While there are many reasons headaches occur, dehydration is one contributing factor to keep in mind.
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Dark urine or a lack of urine – Dark yellow urine or no urine at all is a sign of dehydration. When the body is running low on water, it stops flushing fluid through the kidneys and the bladder stops filling. If you are not urinating normally, you are probably dehydrated.
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Dry, sunken eyes – If your eyes feel dry or are taking on a sunken appearance, it is likely that your body is low on fluids.
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High body temperature – The body’s fluids don’t just keep things lubricated and feeling comfortable, they help regulate temperature, too. If you have an elevated temperature, it is very likely that you are dehydrated.
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Muscle cramps – Muscle cramping is a sign that serious dehydration is underway. While there are other reasons it can happen, inadequate fluid balance is a prime suspect.
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Lethargy and fatigue – As the body slows down due to inadequate circulation caused by dehydration, lethargy and fatigue can result.
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Poor skin turgidity – Turgidity is the ability of the skin to remain elastic and firm. When water loss occurs, the skin slowly loses its ability to remain pliable, and it feels less firm. It may even take on a wrinkled appearance. You can pinch the skin on the back of your knuckles to test turgidity; if it snaps back, you are probably well-hydrated. If it stays folded or slowly drops back into place, you should increase your fluid intake.
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Low blood pressure – Low blood pressure is a major indicator of dehydration, particularly if your blood pressure drops when you stand up immediately after sitting or lying down. Dizziness can occur as a result.
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Rapid heartbeat – When blood flow is reduced due to dehydration, the heart begins to beat faster to keep what’s left circulating through the body. If your heart rate is elevated and stays that way, you could be dehydrated.
Preventing Dehydration
Luckily, dehydration is a simple problem that is easy to prevent and relatively easy to reverse in mild cases.
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Stay hydrated. Drink plenty of water when you wake up each morning, and keep drinking water throughout the day. Drink up just before diving, and enjoy another drink of water after your dive.
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Check your urine. It should be clear to light yellow. If it is dark colored, you probably need to increase your fluid intake.
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Don’t simply rely on thirst, as we are sometimes dehydrated by the time we feel thirsty.
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Drink more in hot weather. The warmer the weather, the more you need to drink. If you are exerting yourself, you may need to add a sports drink; just be sure to keep drinking pure water at the same time.
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Take breaks. This is particularly true if you are not used to the weather or if you are not used to exercising on a regular basis. Check in with yourself, take it easy, and keep taking in small amounts of fluid to ensure you stay hydrated.
Finally, care for yourself by limiting the amount of caffeine, alcohol, sugar, and salt you take in. All of these substances can increase your risk of dehydration. Keep water on hand and sip away. The better hydrated you are, the better you’ll feel – and the more you will enjoy diving and other activities.