Hot Tubs Bad?

[ronski101]

Does anyone (DAN?) have any statistics on DCS hits caused by hot tub usage after a day of diving? I have heard of wive's tales saying it can lead to getting a DCS hit. I think there was an instance a few years back where a diver got hit and it was blamed on the hot tub and all the contributing factors (stress, out of shape, alcohol, tired, dehydration) were ignored.

I personally get cold easily and always use a 3mm so if there is a hot tub available I am in it to warm back up after a day of diving but then again I am pretty much a chicken when it comes to safety keeping well rested, hydrated, fit. and take extra time during my safety stop and follow that new fangled device us divers now got called a dive computer which by the way only approximates the amount of N2 you have accumulated.

I feel the hot tub actually helps my body out gas more easily, faster and more thorough because it increases circulation, expands blood vessels, and most importantly removes that pesky excess nitrogen that had accumulated during the days diving activities. Sooo, after a weeks worth of diving I am better off nitrogen wise than if i had not used the tub at all.

If I am so close to the ragged edge of a DCS hit stepping into a hot wouldn't make any difference.

Wouldn't it be nice to have a meter similar to a diabetes tool that would scan a drop of blood so you would know how much excess nitrogen you got in your blood every evening on a multi dive/day trip?

Is there really any statistics out there or is it all wives tales designed to scare you?

Ok, i have rattled enough cages and just put my flame proof armor on so all you lemmings can have at it......

 

[knotical]

Alert Diver | DAN Experts Answer Your Medical Questions
second question down

As with so many things, apparently it depends. Dr, Pollock recommends waiting a bit and/or using a lower temp.

 

[tbone1004]

far more than an old wive's tail, rapid heating of the skin can very easily cause skin bends, more pronounced if you are diving in cold water, but you should wait a few hours before taking hot showers, and hot tubs are that much worse.

So, N2 in the blood isn't the problem, it's N2 in the skin. When your tissues are cold, they ongas slower, but also offgas slower, a rapid temperature change from cold to hot is the same as a rapid ascent, do it at your own risk. You are right, the hot tub does increase your bodies ability to offgas, the issue is it does it so rapidly that the end result is no different than blowing decompression or having a rapid ascent that will promote skin bends. Pod Diver Radio actually had a really good episode a month or so ago where Dr. Pollock addressed this type of issue with hot showers, and heated undergarments

 

[DocVikingo]

When your tissues are cold, they ongas slower, but also offgas slower, a rapid temperature change from cold to hot is the same as a rapid ascent, do it at your own risk. You are right, the hot tub does increase your bodies ability to offgas, the issue is it does it so rapidly that it is no different than blowing decompression or having a rapid ascent and that will promote skin bends.

Hi tbone1004,

I am pretty familiar with diving physiology & medicine and am entirely unaware of any published research or even credible opinion that supports the above assertion. Could you please provide such source material?

Thanks.

DocVikingo

 

[tbone1004]

from what Pollock said in the interview and in person, when then tissue compartments open up with increased heat it allows the bubbles to come out of solution faster than they can be removed, so the net result is similar to you making a rapid ascent where the tissues can no longer keep the bubbles in solution. Not a pressure differential in the same sense, but the temperature of the tissues is directly related to their ability to ongas and offgas nitrogen. He has a couple papers on ideal thermal conditions for diving and cites some studies that had been done

 

[DocVikingo]

Hey tbone1004,

I did not listen to the radio interview you mention, but I am familiar with Dr. Pollock's papers on thermal conditions for diving & associated references and to the best of my knowledge none of these state that immersion in a hot tub soon after diving "is no different than blowing decompression or having a rapid ascent...."

Where might I find this?

Regards,

DocVikingo

 

[tbone1004]

that's where I was trying to clarify in the second that while the physiological reasons are different, the net result is getting bent due to the change in tissues having a change in saturation levels. Edited my original post to reflect that, but the point still is that whether you are changing pressure on the tissues, or changing their temperature, they go to a point where the bubbles are no longer able to be held in solution. Different causes, same effect.

 

[DocVikingo]

...but the point still is that whether you are changing pressure on the tissues, or changing their temperature, they go to a point where the bubbles are no longer able to be held in solution. Different causes, same effect.

Hi tbone1004,

Yes, at base it's all simply a matter of Henry's Law of 1803 which demonstrates that the amount of a dissolved gas in a fluid is dependent upon temperature & the pressure above the liquid.

However, very much more information than has as yet been presented in this thread, or anywhere else as far as I know, would be required before it would be even remotely defensible to state with any precision that immersion in a hot tub soon after diving "is no different than blowing decompression or having a rapid ascent...." After all, matters of degree across a wide array of factors seem to be significantly involved in the probability & severity of DCS.

Regards,

DocVikingo

 

[tbone1004]

I agree, but you agree that getting into a hot tub with a rather high loading of N2 in the tissues will put you at a severely high risk of skin bends due to the rapid change in offgassing speed of the tissues?

 

[dreamdive]

Just because something makes theoretical sense does not mean it actually happens. That is why studies (controlled) are there to prove or disprove conjecture or theory.

I have not listened to the radio presentation by Neil Pollock, but I am also not aware of any studies being done to prove/disprove this. Since you mentioned that he stated that the use of heated undergarments may be contributing, I am a bit taken by surprise. I don't wait until I am ice cold to turn mine on. Rather, the vest is on to PREVENT me from getting too cold.

I guess one could challenge Neil on were he gets this information from.

Regards,