Dehydration

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At a lower level we see dehydration related headaches and occasionally vomiting a lot - far more than any other ailment.

Dehydration is one of many things that can cause headaches. I've put together a piece on "Headaches and SCUBA Diving", where dehydration is briefly discussed.
 
Get hydrated or get bent. Fact.
I'm going to reevaluate my prior post in light of this persuasive evidence. Thanks.
 
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Hydration has become one of the most misunderstood and overly complicated topics in diving, fitness and general health and living discussions. As a scuba instructor and certified fitness trainer, I'm often asked questions relating to drinking water, sports drinks, and other food and beverage intake as related to safety in diving and performance in exercise.

Hydration has been such a fad for so long that I believe we have a generation of youth who have never exercised without a water bottle and cell phone in hand.

The human body is an incredibly complicated mechanism for sure. My athletic performance suffers when I consume water or any other fluids beyond a glass prior to exercise. During a 45 to 1 hour minute gym workout, I will normally only take couple sips of water from a fountain if my exercise intensity has made me thirsty. Prior to a 30 minute to a 1 hour run, I'll normally drink a Monster Java or a can of Coke or Pepsi. My body discovered a love affair with caffeine prior to cardio 20 years ago in college. If I do high intensity interval training on a track, drinking anything prior to working out doesn't seem to help. Instead, I need to consume juice, water or G2 well in advance of a sprint/recovery jog/sprint/recovery jog style workout.

In diving, dehydration most likely aggravated a case of minor DCS after a 180 foot air dive in 1989. I had been having stomach/intestinal trouble with diarrhea the morning of the dive. After taking am Immodium I felt like I could enjoy the day and decided to dive. The 180 was not the original plan. We changed it underwater while diving a blue hole. I surfaced with tingles and minor joint pain in my knee, elbow and shoulder after deco. At first I felt like I had been stabbed with an ice pick, then the joints had a dull ache. I reported it to the boat captain who refused to put me on oxygen because I probably just had "the worries" and if I had really been bent I would be screaming in pain. You have to remember that things were more black and white in the 1980's. Most diving instructors never heard terminology like "sub-clinical DCS". Now, DAN talks about "PADI-itis" in which a middle-aged diver who seldom exercises and dives on vacation once or twice a year reports "fatigue" and "body aches" and wants oxygen and a chamber after lugging bags from his home, through the airport, into the hotel and out on to the boat the day after arrival with little rest.

My friend, Jim Wyatt, one of the most active cave instructors in Florida hydrates for deep dives well in advance, but you don't see him pounding water at the last minute. Another friend and cave instructor, John Orlowski, like myself, rarely drinks water. He tells a story about realizing that he was really thirsty so he decided to drink some tap water. His wife, Shelley who used to teach a lot of cave trimix courses, returned home to find him drinking water. She was a nurse who wanted to put him on O2. Since John never drank water she figured he must be bent and trying to load water to help aid gas elimination. "No, I'm just thirsty!" John replied.

While I'm not going to say hydration isn't important. It's also a bit of a myth that we are all walking around dehydrated. We live in a world with growing obesity partly because portion sizes have become so large. Compare our servings today to what was on a plate in the 1940's or 1950's as well as plate sizes themselves. I just drank a glass of milk in which the glass actually would be two cups or two servings. A standard "glass" of water is really two or more servings. We are getting more water in our diets in many forms today while diving nitrox than divers were getting in the 1950's and 1960's while diving below 100 feet on air.

Yet, divers are pounding water for a 60 foot dive on Nitrox 32. I could hear so many people reading this saying, "Better safe than sorry," but it's one thing to want a little more hydration for a 200 or 300 foot trimix dive and literally be pounding water in the hours leading up to the dive than for the average dive. Back in the day 300 foot dives were done safely on air and hydration wasn't really a thought.

Consuming water is a good habit. Even too much of a good thing can be bad. Too much water can lead to reducing needed sodium. By following the simple old-fashioned advice of eating a balanced diet of fruits, vegetables, whole grains, fish, poultry, and occasional red meat while consuming milk, juice, water and other flavored beverages from coffee to tea and sports drinks, the average person will be nourished and hydrated enough for safe diving. There are always exceptions and those with special diet needs, food allergies or who choose lifestyles such as vegetarianism or veganism may need to adjust their intakes accordingly.

While there are many great articles on hydration needs a quick search located this:

The Truth About Water.
 
Thank you Trace. I've always felt that if you need to pee underwater, you have too much liquid inside. Until someone goes hiking in the desert and their lips crack, they have no saliva and can barely speask, they have no idea what it means to be dehydrated. Breathing air underwater for an hour or so is not what I would call dehydration.
 
Thank you Trace. I've always felt that if you need to pee underwater, you have too much liquid inside. Until someone goes hiking in the desert and their lips crack, they have no saliva and can barely speask, they have no idea what it means to be dehydrated. Breathing air underwater for an hour or so is not what I would call dehydration.

I managed to dehydrate to the point of vomiting 3 times last year from just diving. Its not always cracked lips and no saliva.
 
My friend, Jim Wyatt, one of the most active cave instructors in Florida hydrates for deep dives well in advance, but you don't see him pounding water at the last minute.
While I fully agree that you will not see him pounding water before a dive, he does feel that hydration is important. In a discussion about equipment, he told me that a diver who does not have a P-valve on a dry suit is essentially announcing that he or she is willing to risk DCS. He said that is because such a diver is likely not to hydrate sufficiently because of a fear of having a strong urge to urinate during a long dive.
 
The human body is an incredibly complicated mechanism for sure. My athletic performance suffers when I consume water or any other fluids beyond a glass prior to exercise. During a 45 to 1 hour minute gym workout, I will normally only take couple sips of water from a fountain if my exercise intensity has made me thirsty. Prior to a 30 minute to a 1 hour run, I'll normally drink a Monster Java or a can of Coke or Pepsi. My body discovered a love affair with caffeine prior to cardio 20 years ago in college. If I do high intensity interval training on a track, drinking anything prior to working out doesn't seem to help. Instead, I need to consume juice, water or G2 well in advance of a sprint/recovery jog/sprint/recovery jog style workout.

I love water, and I drink a fair amount of it. Coffee in the morning, tea after dinner, water the rest of the time. Nothing more refreshing than ice cold water, except ice cold fresh brewed sun tea...and BEER.

For my summer workouts, at least on the bike, I range from 1-4 hours on hot pavement, and I drink 1-2 bottles an hour. 1 water and 1 weak gatorade.

Back when I was serious about training and racing, and if I ever get back to it, I cut caffeine out of my diet. I found that it did help my training and recovery, but more so on race day I would double up on the dark coffee. Caffeine is one of the better legal performance enhancers but for me, I build a tolerance too fast.


Until someone goes hiking in the desert and their lips crack, they have no saliva and can barely speask, atithey have no idea what it means to be dehydrated. Breathing air underwater for an hour or so is not what I would call dehydron.

Been there done that, woke up in the back of an FLA with an IV sticking out of my arm, in a sleeping bag in 100+ degree heat shivering.

You are right, diving is not gonna dehydrate you. Drinking lots of booze at night will though, and a lot of us enjoy our drinks after a day of diving.

For those people who are at less than ideal hydration levels, waiting until you get on the boat is pointless. You're just gonna pee it out. Hydrating starts at least a week before the dive trip but the best thing you can do is not get drunk, alternate a beer with a glass of water after diving, and drink water, juice or sports drink as needed to quench thirst during the day.

:coffee:
 
For those people who are at less than ideal hydration levels, waiting until you get on the boat is pointless. You're just gonna pee it out. Hydrating starts at least a week before the dive trip
This idea that you have to hydrate well in advance is frequently asserted by hydration enthusiasts. Does your body expel water that it needs because you didn't anticipate those fluid needs a week in advance? That doesn't seem like a winning strategy from a natural selection perspective and a quick google search didn't turn up evidence to support (or refute) it. Is there scientific evidence to support the claim?
 
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Unfortunately, there isn't convincing evidence that, for recreational divers, hydration commonly plays a significant role in DCS pathophysiology. Nevertheless, there's probably a tendency for people to cite dehydration as the root cause in unexplained DCS cases.

In the absence of truly understanding a phenomenon such as DCS, people will "fill in the gaps" with whatever is convenient or whatever seems to make sense. People like to feel in control. I think we can extend this same psychology to scuba divers. They like to feel they're doing everything they can to minimize DCS risk. Hydration is an easy answer. Avoiding caffeinated beverages is an easy answer. It's achievable. Pound water during that surface interval. Feel good about yourself. :coffee:
 
For those people who are at less than ideal hydration levels, waiting until you get on the boat is pointless. You're just gonna pee it out.
:coffee:

This is just false.

If you drink ten glasses of water and sit on the couch for 5 hours then you will need to piss. Yet, if you drink water and are active and sweating and exerting yourself then your body will be using that water. Yet, you do need to start hydrating the night before or that morning. But how much water you drank on Monday will not affect your hydration level on Thursday or Saturday.
 

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