Strenuous Exercise and Diving....what was that consensus again?

[Cacia]

If I did 20 miles with HR exceeding my target zone by 20 bpm (in other words, "pushing it")....how long before you think I should dive safely? I was going to dive this PM, finished the ride at around 10 am.

Is it the lactic acid..or what that causes the issues? And once someone explains the theory, please give me an example of applying it and what factors to consider. (duration, level of intensity...etc) (please)

 

[Charlie99]

I thought the danger was strenuous exercise immediately AFTER a dive; with the reason being that heavy exertion promoted bubble formation because high stresses on joints can cause localized low pressure pockets that generate gas around existing micronuclei. I've also seen the term tribonucleation applied to this sort of phenomena.

Dr. Deco is a very strong proponent of avoiding heavy exertion immediately after a dive -- such as climbing up a boat ladder in a heavy set of doubles.

 

[nereas]

I once spent an hour hauling all my gear to the beach by myself, then went diving right away and got really narked badly at depths that you would not expect it to occur. CO2 loading is the major issue regarding exertion before a dive. If you exercised heavily during the day, then I do not believe you should dive on that day at all. Wait until the next morning, after a good night's sleep.

Exercising after a dive presents a DCS risk. Therefore waiting until the next day, the same rule as for flying, for the same reasons, is warranted. As long as there is elevated N2 in your blood and body tissues, exercising is not a good idea. And we know that elevated N2 lasts up to 12 hours or longer. Therefore I would wait at least a full 12 hours, if not 24.

 

[Cacia]

Thanks

you guys give good answer

I know to take it easy after deco, but I thought there was this marathoner who posted here once about wanting to stick to his training program on vacation, run his 15 miles before his 8 am dive and people told him that it was not a good idea.

high stresses on joints can cause localized low pressure pockets that generate gas around existing micronuclei.

that's interesting.

 

[Charlie99]

The first item returned on a google of "tribonucleation" is Production of gas bubbles in fluids by tribonucleation -- Ikels 28 (4): 524 -- Journal of Applied Physiology, a 1969 abstract that mentions a test where rolling a metal ball around inside a glass tube created visible bubbles from a dissolved gas, "under relatively mild experimental conditions, such as may be encountered in vivo".

Dr. Michael Powell, aka Dr. Deco very strongly promotes this sort of phenomena (although he doesn't use the term tribonucleation) as a possible cause of many cases of DCS.

slight hijack --- a related phenomena is the formation of gas bubbles by the low pressure spots created by a spinning propeller. The formation, then collapse, of the bubbles can generate forces that eat away at a prop pretty quickly.

 

[Cacia]

Charlie,

I, like many people, stand in awe of you.

Thank you so much for always posting great knowledge.

I hope to get to meet you some day.

Your propeller analogy was great. I value your posts more than you will ever know.

The ability to articulate physics in an understandable, concise way is a gift. If you wrote a column, I would go out and buy it everyday.

 

[grazie42]

I think the consensus is that pre-dive exercise is ok, possibly good. Post-dive exercise is bad. With pre-dive exercise the thing to watch out for is other predisposing factors like dehydration etc...

Here´s a link to a post by Cameron Martz on TDS about pre-dive exercise (it has links to studies):
The Deco Stop
and one about post-dive exercise:
The Deco Stop

 

[Mariesonny]

slight hijack --- a related phenomena is the formation of gas bubbles by the low pressure spots created by a spinning propeller. The formation, then collapse, of the bubbles can generate forces that eat away at a prop pretty quickly

I believe its called cavitation.

As for me....diving sounds like a good excuse to skip exercising.

 

[Fish_Whisperer]

When I lift containers of fluid after the dives are done, I try only to do it in 16 oz. containers, and I am careful about lifting them too quickly...

 

[Cacia]

With pre-dive exercise the thing to watch out for is other predisposing factors like dehydration etc...

good point.

Do most of you think dilute urine, the "p test" is an accurate way to gauge hydration status?

thanks for links Gracie. Cameron knows some stuff, I liked his view on Gatorade being counter productive (kidneys don't get triggered to conserve salts or something)

So..exercise and 3-4 hrs later should probably be okay for a conservative dive profile, I am taking from all this.