Oxygen "debt"

I think this essentially boils down to which energy system is primarily being used. In all out sprints lasting in the vicinity of 10 seconds or less, such at the 100 yard running dash (well, for me, make that the 35 yard dash-waddle), breathing doesn't matter for performance because the muscles are being powered by the anaerobic respiration system (i.e., fermentation.) In very long events, such as the marathon, the vast majority of muscular activity is fueled by the aerobic system, which, as its name suggests, requires air. Swimming doesn't have events that last 10 seconds or less (unless you count the 25 yard sprints in our Y league), so even the shortest official events tap into at least a little bit of the aerobic system along with the anaerobic system. However, it seems to me that it takes time for oxygen in the lungs to make it to the muscles, so when Anthony Ervin does his 19 second 50 yard sprint, I suspect air breathed during the race itself does not reach his muscles in time to do any good--hence the lack of taking many (if any) breaths. On longer sprints, like the 100, then oxygen probably does have enough time to circulate to the working muscles, so you wouldn't want to avoid breathing here! Even during 50s, sneaking a breath or two during the race will make you recover faster after it's over--and in the case of some of us older fellows, perhaps help guard against premature demise. In terms of the CO2 being the stimulation of the urge to breathe, I had this demonstrated last summer in Colorado when I was working on an article on altitude sickness. I went into a hypobaric chamber, went up to a simulated 18,600 feet (i.e., Mt. Everest base camp), and with a pulse oximeter had my blood oxygen saturation level measured at 71 percent. (Normal at sea level is 98-99%). I felt fine--absolutely no sense whatsoever of being at all oxygen deprived, despite the fact, as one researcher told me, that if I had showed up at an emergency room with 71 % ox sat, they would have rushed me to an intensive care unit. Later, when I emerged from the chamber and was more or less normal again, I tried to see how low I could get my oxygen sat level by holding my breath. After a minute and 15 seconds, I only got it down to about 93% (I was in Boulder, so my baseline was 96% at this altitude), but it felt awful. I am sure the accumulated CO2 was responsible for the overwhelming urge to breathe; in the chamber, I was "blowing off" CO2 with each breath I took of the thin Mt. Everest-base-camp like air, so there was no accumulation to make me feel miserable... But this is a digression. What was your question? Just joking. My best advice: breathe as much as you want in 100s and longer; take zero breaths on 25 sprints (if your league ever has these); and one breath up, two back maximum on most 50s.

I think this essentially boils down to which energy system is primarily being used. In all out sprints lasting in the vicinity of 10 seconds or less, such at the 100 yard running dash (well, for me, make that the 35 yard dash-waddle), breathing doesn't matter for performance because the muscles are being powered by the anaerobic respiration system (i.e., fermentation.) In very long events, such as the marathon, the vast majority of muscular activity is fueled by the aerobic system, which, as its name suggests, requires air. Swimming doesn't have events that last 10 seconds or less (unless you count the 25 yard sprints in our Y league), so even the shortest official events tap into at least a little bit of the aerobic system along with the anaerobic system. However, it seems to me that it takes time for oxygen in the lungs to make it to the muscles, so when Anthony Ervin does his 19 second 50 yard sprint, I suspect air breathed during the race itself does not reach his muscles in time to do any good--hence the lack of taking many (if any) breaths. On longer sprints, like the 100, then oxygen probably does have enough time to circulate to the working muscles, so you wouldn't want to avoid breathing here! Even during 50s, sneaking a breath or two during the race will make you recover faster after it's over--and in the case of some of us older fellows, perhaps help guard against premature demise. In terms of the CO2 being the stimulation of the urge to breathe, I had this demonstrated last summer in Colorado when I was working on an article on altitude sickness. I went into a hypobaric chamber, went up to a simulated 18,600 feet (i.e., Mt. Everest base camp), and with a pulse oximeter had my blood oxygen saturation level measured at 71 percent. (Normal at sea level is 98-99%). I felt fine--absolutely no sense whatsoever of being at all oxygen deprived, despite the fact, as one researcher told me, that if I had showed up at an emergency room with 71 % ox sat, they would have rushed me to an intensive care unit. Later, when I emerged from the chamber and was more or less normal again, I tried to see how low I could get my oxygen sat level by holding my breath. After a minute and 15 seconds, I only got it down to about 93% (I was in Boulder, so my baseline was 96% at this altitude), but it felt awful. I am sure the accumulated CO2 was responsible for the overwhelming urge to breathe; in the chamber, I was "blowing off" CO2 with each breath I took of the thin Mt. Everest-base-camp like air, so there was no accumulation to make me feel miserable... But this is a digression. What was your question? Just joking. My best advice: breathe as much as you want in 100s and longer; take zero breaths on 25 sprints (if your league ever has these); and one breath up, two back maximum on most 50s.