1. Diving after flying.
Some dive medicine sources take what I see as an excessively conservative stance on this, e.g., wait 24 hours. The below is from our own Scubadoc in response to an e-mail question:
"When is it safe to dive after flying, especially if I had an alcoholic drink on the plane? Rick Tolbert Charlotte, N.C.
There are no guidelines concerning the time to dive after flying or having alcoholic beverages. However, mild dehydration can occur on long flights and alcohol consumption (and drinking caffeinated beverages) contributes significantly to dehydration. Dehydration is a definite risk factor in predisposing a diver to decompression illness because the washout of inert gas (nitrogen, in diving) is less effective in a dehydrated individual. There are few dive trips that don't start out with a complimentary rum punch (often provided by the dive operator), and one free drink often escalates into severalon top of what you might have had on the plane during the trip. There is a small uptake of nitrogen back to sea level partial pressure upon descent and exit from the aircraft. Residual nitrogen is referenced to nitrogen tissue levels above normal sea level values and a flight at 8,000 feet cabin altitude would result in lower tissue nitrogen levels than sea level. On descent, tissue nitrogen pressure would simply return to sea level amounts.
We should expect to see more decompression illness on the very first day of diving if there were a relationship between flying and drinking alcohol before diving. The Divers Alert Network (DAN) has reported some data suggestive of an increase in decompression accidents on the first day of diving of a trip. Their figures show that of the 88 cases reviewed from the Caribbean for 1994, 33or 37.5 percentoccurred on the first day. The remainder occurred on days two through seven. These numbers are far too small to establish a cause and effect, but are suggestive. It would certainly seem reasonable to wait at least 24 hours before diving, rehydrating yourself as much as possible and avoiding overkill with the alcohol."
IMHO, this is unnecessarily inflexible. The conservatism appears to be based on a number of factors, which, individually or in the aggregate, are to some extent controllable and may or not reasonably advise a break between flying & diving.
Given that it's reasonable, I often dive as soon as possible after landing. For me, this means I just flew to Cozumel, not to Fiji.
You should endeavor to drink as much as possible to counteract the drying effects of air at altitude, and keep alcoholic & caffeinated beverages to a minimum. Also, get as much rest as you can.
If you arrive alert, well rested, well hydrated, feeling fine & in good spirits, diving shortly after flying likely adds no additional concerns. If you're jetlagged, dehydrated, fatigued, feeling lousy & irritable, then it might be wise to save the scuba for the next day when you're recovered. BTW, N2 level from flying is not an issue.
2. Diving after skydiving.
If you arrive alert, well rested, well hydrated, feeling fine, in good spirits & injury free, scuba diving shortly after skydiving likely adds no additional concerns. If you're jetlagged, dehydrated, fatigued, feeling lousy, irritable and have aches & pains, then it might be wise to save the scuba for the next day when you're recovered. BTW, N2 level from skydiving is not an issue.
Best regards.
DocVikingo
