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> > >On Thu, 21 Sep 1995, Dan Volker wrote: > >> VO2 max will be the critical measurement because it not only relates the >> rate of gas exchange, it does it in relation to the volume of the >> individual's body (and of course larger volumes hold more dissolved >> gas)...As VO2 max goes up, usually the volume or weight of the person is >> decreasing. Very large people have typically low VO2 max values even if they >> have a powerful heart, because there is so much volume for transfer to take >> place within. >> Dan >> > >dan: >aren't VO2Max measurements done at heartrates of >180-210 bpm (with the poor subject on an ergonometer with tubes, hoses, >wires dangling)--at the break between aerobic/anerobic effort? does >this really apply to diving? > Hello Erich, We would use a polar heart rate monitor (vantage xl--the one that downloads to a pc) to run a Conconi test to determine Anaerobic threshold as a starting point---this is what you are referring to. In this test a person gradually increases cycling or swimming speed over multiple laps, and the computer plots out speed/distance data with corresponding heart rate. At the point of anaerobic threshold (also called the deflection point) the line begins to curve down, indicating heart rate can no longer keep pace with continued or increased exertion, and at this point the body has crossed over into anaerobic resperation. The heart rate monitor is a a watch style reciever and a radio transmitter on a chest band (both waterproof to 30 feet). Your some people will hit their deflection point at 150, some at 180, 200 etc. When units of work and body weight are added, we can arrive at VO2 max. MAJOR DIFFERECES in VO2 max exist between individuals, EVEN at competitive levels. Even in your own body, if you weighed 185 pounds, and lost 15 pouunds, your VO2 max would increase dramatically. The reason this is important is that not form the basic metabolic differences between people, but from the gas exchange differences. If I, as a competitive cyclist was measured next to a "couch potatio", you would see that I can deliver far more oxygen to EVERY CELL in my body than can the "spud", and that I can rid FAR MORE CO2 from my cells and bloodstream as well. This occurrs because I will pump far more blood through my lungs per minute, and the blood will have been distributed over a far greater area within the body in that same minute, even at VERY low heart rates. This also causes me to in gass far more N2 on a 200 foot dive than my buddy the spud. But when we begin our series of stops I will clean out all my tissues better than the spud, and the gradient I produce from superior exchange rate in the lungs will quickly alter to the point that I have less saturation of N2 then would the spud. So on a NO-STOP 60 for 60 profile, I'm in more danger ....but in any intelligent profile with significant deco stop added I can end up cleaner and safer. >it's my recollection that the difference between VO2max for elite and poor >fitness was about 50% when fractioned by body mass. so a stud can use 2x >as much O2 as a dud at max output (and hence come up with more energy to >out-put). performance-wise this would translate >to a the stud's world championship cycling time trial feeling like a ride in >the park for the dud. if our champ went for a dive in the park, his O2 >(or just gas) consumption rate would be much lower than during the tt--and >nowhere near his VO2 max. > >i'd think the low >%fat, large potential O2 window (due to large arteriovenous O2 extraction), >low heartrate, increased perfusion and ventilation of an athlete would >outway any danger. > The athlete will not have the problem with the slow tissue the overwieght person would have, but I'm concerned about the blood, muscle, brain, bone etc., that will have saturated faster in the athlete. While the athlete may do the dive at a heart rate of 85 bpm and the spud at 110, the volume of blood pushed by the athlete with his far greater stroke volume (thats how much blood you push per heart beat, not how many people flame George) will be much greater....more blood=greater volume exposed to N2 gradient of whatever depth and duration both of these divers do. And the smart athlete will maintain a higher heart rate on deco than on the deep portion of the dive i.e., no catatonic, Zen hangs---spiral swim at each deco stop... . I think you are right about the O2 window, that the athlete would have an advantage there. Regards, Dan >btw, the one ref. that comes to mind about a bent athlete was reported by >the institute for nautical archaeology a few years ago. one of their >divers did a hard workout got DEHYDRATED and bent the next day diving. or >maybe it was just grade 4 bubbles.... > >regards, eric > > >_____________________________________________________________.sig >Eric Maiken email: eapg243@ea*.oa*.uc*.ed* >Dept. of Physics o: 714 824-6621 >U of California fax: 714 824 2175 >Irvine, CA 92715-4575 > > > > Dan Volker SOUTH FLORIDA DIVE JOURNAL http://www.florida.net/scuba/dive 407-683-3592
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