Exercise and repetitive diving?

[OralDouglas]

Hey all...

Ive got a few questions, sorry to cross post, but Ive been told that this is the best place to ask!

Anyway!
I am usually quite physically active, and have been known to maintain a fairly rigorous gym schedule (5 days a week, heavy weights, high intensity) while on dry land. This summer I am going to be doing a few liveaboards, as well as taking a DM course.

Now, I realize I will be pretty taxed physically with the course- but I was wondering if it would be wise to try and maintain a moderate level of conditioning (say, three or four days a week, one heavy- high intensity day) during this period?

Could all this activity increase the risks of dive related injuries?

Thanks!

[Dr Deco]

Hello OralDouglas:

Evidence from the last several years seems to indicate that physical activity before a dive is beneficial in reducing DCS risk. Current thinking revolves around some biochemical factor, e.g., nitric oxide, which reduces gas bubble formation/growth during decompression. The reduction in bubbles is real even though the reason is speculative.

Years ago, I cautioned against immediate predive physical activity. Recent studies show this unnecessary. It seems as though any micronuclei generated by musculoskeletal activity are squeezed during the bottom portion of the dive and are of no consequence with respect to later decompression.

Remember that exercise during the decompression (surface) portion must be avoided, as the nuclei generated will expand with the dissolved tissue nitrogen.

Dr Deco

[mikeyjoe]

While I am sure the Physiology gurus will offer there advice here, until then, here is what I learned in DM class......

Intenses exercise more than 12 hours prior to a dive has a protective effect with respect to DCS.

Intense exercise less than 12 hours before a dive seems to predispose you to DCS.

Intense exercise immediately after a dive is a big no-no.

So, if it were me, I wouldn't exercise less than 12 hours before a dive, and I wouldn't exercise right after a dive - probably wouldn't until my computer said I was de-saturated......

[mikeyjoe]

There you go - one of the gurus is a faster typer than me!

[Dr Deco]

It is interesting to see that exercise effects post dive are now becoming recognized.

[OralDouglas]

Ok!

Thanks for the info!
If i wait until I have completed my surface intervals and am no longer diving for the day, I should be ok for moderate exercise then?

[DocVikingo]

If i wait until I have completed my surface intervals and am no longer diving for the day, I should be ok for moderate exercise then?

Hi Oral Douglas,

You're on the right track, but let's consider some specifics.

You should not do any strenuous activity during surface intervals or for about 2-4 hours following the last dive of the day. After that time, moderate exercise should not significantly increase risk of DCS. Whatever exercise you do, stay very well hydrated and avoid becoming over-heated.

Something not yet mentioned is what you should do during surface intervals and for an hour or so following the final dive. It is unwise to lay or sit without moving, or take a nap. It is better to remain mildly active, such as taking a stroll or just randomly and gently moving your limbs about. Also, avoid both frigid A/C and high ambient temperatures. Finally, drink plenty of water and perhaps the occasional well-balanced sports drink.

Helpful?

Regards,

DocVikingo

[graywhale]

I read of a case of a diver in COZ who was like you - a heavy weight trainer and trained at night between dives almost daily. He got hit and was sent to the chamber. The only explanation was his intensive weight resistance training. He was well hydrated and never violated the computer, was in great shape, etc....

Based on that example, I would not go to the gym at least 24 hours after any dive, maybe even 48 hours. Certainly not full intensity maximum weight resistance training.

[vladimir]

I read of a case of a diver in COZ who was like you - a heavy weight trainer and trained at night between dives almost daily. He got hit and was sent to the chamber. The only explanation was his intensive weight resistance training. He was well hydrated and never violated the computer, was in great shape, etc....

Based on that example, I would not go to the gym at least 24 hours after any dive, maybe even 48 hours. Certainly not full intensity maximum weight resistance training.

Finally, somebody offers some anecdotal evidence to debunk these scientists' opinions. Thanks, graywhale.

[roturner]

Hello OralDouglas:

Evidence from the last several years seems to indicate that physical activity before a dive is beneficial in reducing DCS risk. Current thinking revolves around some biochemical factor, e.g., nitric oxide, which reduces gas bubble formation/growth during decompression. The reduction in bubbles is real even though the reason is speculative.

Years ago, I cautioned against immediate predive physical activity. Recent studies show this unnecessary. It seems as though any micronuclei generated by musculoskeletal activity are squeezed during the bottom portion of the dive and are of no consequence with respect to later decompression.

Remember that exercise during the decompression (surface) portion must be avoided, as the nuclei generated will expand with the dissolved tissue nitrogen.

Dr Deco

How would you rank this risk factor as compared to other things like working hard on the bottom, fatigue etc.

I'm asking because I'm an avid (albeit not a great) runner. I often run the morning after a night dive, let's say 6-8 hours after the dive. My busy schedule demands that much of my local diving takes place at night and much of my running in the mornings... My dives are usually fairly tame, one every few days, non-repetitive. To take last night's dive as an example, it was 49 min, max 25m, average depth 10m which included about 6 minutes saftey stop.

Would you say I'm running a higher than necessary risk running 8 hours after that dive?

R..