Hot Tubs Bad?

[DocVikingo]

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?

Hi tbone1004,

No, I do not agree with that assertion. As regards the recreational diver, I agree with Dr. Pollock that, "As with many factors, the net response can be positive or negative, depending on the magnitude of the inert gas load & the heat stress" and that hot tub exposure "might facilitate inert gas washout (or inert gas elimination)". My personal interpretation of the published research, expert opinion & anecdotal reports to date is that immersion in hot water immediately following a dive, "even with a rather high loading of N2 in the tissues," likely puts the diver at only a slightly and as yet not determined increased level of risk of DCS.

I also see no reason to limit any posited increased risk to "skin bends," as other "fast tissue compartments" are also warmed by such immersion and all sorts of manifestations of DCS might occur, not just cutaneous.

Regards,

DocVikingo

 

[Dr. Lecter]

Just take your O2 bottle with you - problem solved

 

[knotical]

I just went to Pod Diver Radio, listened to the only recent Neal Pollack interview I could find, and neither hot tubs nor skin bends were mentioned. Is it possible the info came from somewhere else?

 

[boulderjohn]

Let's look at what was actually said by Pollock in the article cited. (The bolding is mine, and the parts in red are my comments.)

Getting into a hot tub immediately after diving does alter decompression stress. As with many factors, the net response can be positive or negative, depending on the magnitude of the inert gas load and the heat stress. The hot tub or hot shower will warm the extremities and enhance peripheral circulation which might facilitate inert gas washout (or inert gas elimination). Sounds good! Get in the tub!

Large inert gas loads, however, can be problematic. Since the solubility of gas is inversely related to temperature, tissues will hold less in solution as they warm. Warming tissue with significant gas loads can promote bubble formation. Since the warming of the superficial tissues precedes the increase in blood flow, such bubbles can pose problems before the increased circulation can remove them. There is no simple formula to compute what constitutes a minor, significant or substantial peripheral inert gas load. The actual conditions vary as a function of the individual, thermal protection, physical activity and dive profile. So, if we have a significant gas load (nearly bent?), it is theoretically possible that it could create bubbles.

My approach is to stack as many factors as possible in my favor to compensate for the Murphy effect we frequently see in decompression sickness. I encourage a simple rule of thumb: delayed gratification. Enjoy the thought of the hot tub or shower for a while instead of jumping in immediately. An interval of 15 to 30 minutes should help you avoid some of the risk, as will keeping more conservative dive profiles. Another compromise would be to employ a lower temperature in the hot tub or shower.Ah, so to play it safe, we should wait 15-30 minutes after diving before getting in the hot tub. I usually have no trouble getting my gear off, getting to a hot tub, and immersing myself within 2-3 minutes, so this will be a major inconvenience, no doubt, but maybe I can handle that much of a delay if I really, really control myself.​

When I read this, I have trouble seeing how people are reading this as a warning against going into hot tubs after diving. When I read it, I feel encouraged to go ahead.

 

[DocVikingo]

When I read this, I have trouble seeing how people are reading this as a warning against going into hot tubs after diving. When I read it, I feel encouraged to go ahead.

Hey John,

Anecdotally, a number liveaboards, where residual nitrogen loads can be high, have hot tubs on them, albeit all that I've tried have had tepid & not hot water in them. I am unaware of any reported hits that could be confidently attributed to hopping into them post-diving.

However, below is an earlier thread on this topic with some comments from DrDeco who concludes that the jury is still out on hot water immersion very soon after diving but that some caution may be prudent --> http://www.scubaboard.com/forums/archive/index.php/t-9333.html

Cheers,

DocVikingo

 

[tbone1004]

thanks for clarifying guys. I do prefer to partake in a few vasodilating beverages post diving, and I certainly don't argue with hot tubs, but I usually do try to wait until at least after dinner when I've had a few hours to stabilize. I also run with a pretty conservative tissue loading setting on the Petrel, so at 30/70 I'm not particularly concerned for myself, but I wouldn't hop into a hot tub right after getting out of Monterey Bay in a 3mm....

 

[Drin]

Hey John,

Anecdotally, a number liveaboards, where residual nitrogen loads can be high, have hot tubs on them, albeit all that I've tried have had tepid & not hot water in them. I am unaware of any reported hits that could be confidently attributed to hopping into them post-dive.

I asked Tom (the then-captain of the Truk Aggressor) about their hot tub temperature in 2004. He replied that corporate policy was to keep the water temp at 99 degrees - just warm enough that it registered as warmer than the human body. "Just in case".

-Adrian

 

[Dr. Lecter]

I asked Tom (the then-captain of the Truk Aggressor) about their hot tub temperature in 2004. He replied that corporate policy was to keep the water temp at 99 degrees - just warm enough that it registered as warmer than the human body. "Just in case".

I'll add that to my list of reasons to avoid Aggressor-affiliated boats. May as well run a bath at that point.