Had an "interesting" experience yesterday, which I thought I would share with the board.
I was doing dives #3 and #4 of my search & recovery speciality, and my instructor (who I now believe is a closet sadist) found the only place in the British Virgin Islands with relatively low visibility and a current for the circular rope search drill (to be fair, he asked us if we were comfortable with the location), and then hid the objective at the extreme range of the search, down current from the boat. The bottom was flat and so our depth only varied between 57 and 61 feet, and we were only down for 42 minutes on dive #3, but I felt extremely tired and very ropey when we got back to the boat, and I could feel a decent headache coming on.
We did the minimum one hour surface interval, and then back in for training dive #4. The instructor must have had a bit of sympathy seeing how shattered we were after the previous dive, because we were in and out in 26 minutes (same depths) for the last dive. On neither dive did we do a safety stop because we were shepherding a lift bag with a heavy object attached up to the surface.
On the boat ride back to the dock I felt increasingly dicey - strong headache, nausea and overall fatigue. I didn't worry too much about the headache or fatigue because we had worked pretty hard, and I used to clean the underside of boats on scuba, and always used to get headaches. The nausea worried me a bit, but I didn't have any of the classic symptoms of DCS. I made it to my car before having a good vomit, and then went home and rested for the remainder of the afternoon (feet elevated just in case).
After about 5 hours the nausea and the headaches subsided, as did much of the fatigue. I am pretty certain that the experience was not DCS related (I can accept that strenuous exercise will accelerate risk, but we were a long way within safety margins, and as mentioned, no classic symptoms). But I did wonder what did trigger that reaction. The only thing in the manuals that seemed to potentially fit the symptoms/situation was hypercapnia arising from working too hard down there, but I would welcome any slightly more educated opinions.
Whatever it was, it certainly taught me a couple of timely lessons that (i) I am not 19 any more, and (ii) diving within your limits includes when under instructor supervision.
I was doing dives #3 and #4 of my search & recovery speciality, and my instructor (who I now believe is a closet sadist) found the only place in the British Virgin Islands with relatively low visibility and a current for the circular rope search drill (to be fair, he asked us if we were comfortable with the location), and then hid the objective at the extreme range of the search, down current from the boat. The bottom was flat and so our depth only varied between 57 and 61 feet, and we were only down for 42 minutes on dive #3, but I felt extremely tired and very ropey when we got back to the boat, and I could feel a decent headache coming on.
We did the minimum one hour surface interval, and then back in for training dive #4. The instructor must have had a bit of sympathy seeing how shattered we were after the previous dive, because we were in and out in 26 minutes (same depths) for the last dive. On neither dive did we do a safety stop because we were shepherding a lift bag with a heavy object attached up to the surface.
On the boat ride back to the dock I felt increasingly dicey - strong headache, nausea and overall fatigue. I didn't worry too much about the headache or fatigue because we had worked pretty hard, and I used to clean the underside of boats on scuba, and always used to get headaches. The nausea worried me a bit, but I didn't have any of the classic symptoms of DCS. I made it to my car before having a good vomit, and then went home and rested for the remainder of the afternoon (feet elevated just in case).
After about 5 hours the nausea and the headaches subsided, as did much of the fatigue. I am pretty certain that the experience was not DCS related (I can accept that strenuous exercise will accelerate risk, but we were a long way within safety margins, and as mentioned, no classic symptoms). But I did wonder what did trigger that reaction. The only thing in the manuals that seemed to potentially fit the symptoms/situation was hypercapnia arising from working too hard down there, but I would welcome any slightly more educated opinions.
Whatever it was, it certainly taught me a couple of timely lessons that (i) I am not 19 any more, and (ii) diving within your limits includes when under instructor supervision.
