28 April, 2009
The mammalian diving reflex in action
I went for an early morning swim yesterday, before I went to work, and just to see how hard I was working I put my Heart Rate Monitor (HRM) on. It's a rather old Polar Sport Tester (15+ years) but it's a recording one, so I don't have to distract myself whilst swimming. That said, the transmitter unit that goes around the chest gets dislodged if I swim too fast.
Anyway, whilst doing front crawl my heart-rate was about 120-130 bpm and while resting between sets it was about 95-105 bpm. So when I swim a length underwater (Dolphin kick) you'd imagine something similar, no?
Well, once your head goes under cold (in this case cool) water, and you hold your breath, the 'Mammalian Diving Reflex' kicks-in and you heart-rate should drop, amongst other side-effects. After breathing-up, my heart-rate was 105 bpm as I pushed-off, but, because of the chest band problem I have no recording of heart-rate for the duration of the swim (33M in 48 seconds) but once I stopped the readings re-started and went from 75 to 114 bpm in the space of 15 seconds. The change from 105 at the start to 75 bpm at the end is about a 30% drop in heart-rate, even with mild effort, is quite intriguing.
So, my heart-rate must have slowed, as expected, but I don't know by how much during the swim. I think there's two things for me to try here:
Anyway, whilst doing front crawl my heart-rate was about 120-130 bpm and while resting between sets it was about 95-105 bpm. So when I swim a length underwater (Dolphin kick) you'd imagine something similar, no?
Well, once your head goes under cold (in this case cool) water, and you hold your breath, the 'Mammalian Diving Reflex' kicks-in and you heart-rate should drop, amongst other side-effects. After breathing-up, my heart-rate was 105 bpm as I pushed-off, but, because of the chest band problem I have no recording of heart-rate for the duration of the swim (33M in 48 seconds) but once I stopped the readings re-started and went from 75 to 114 bpm in the space of 15 seconds. The change from 105 at the start to 75 bpm at the end is about a 30% drop in heart-rate, even with mild effort, is quite intriguing.
So, my heart-rate must have slowed, as expected, but I don't know by how much during the swim. I think there's two things for me to try here:
- Try a static test where I just sink and watch my heart-rate for one minute.
- Put a skin-suit or T-shirt on that will stop the chest band from flapping around and then repeat the dynamic test.
Labels: apnea, freediving
16 April, 2009
Gonna get me some Freediving action
After many years of thinking about it I'm finally going to do some Freediving. I've decided to get some introductory training and then join a club, not that there are many to choose from in England.
Not that I'm that bothered about deep dives, none of that No Limits tom-foolery, but I'd like to get my static apena (breath holds) beyond two minutes. My goal would be four minutes for static, and my dynamic apnea (swimming under water) to further than 40m, maybe to as much as 100m but I don't know what the reality of that would be.
I'll set some more realistic goals in between.
Not that I'm that bothered about deep dives, none of that No Limits tom-foolery, but I'd like to get my static apena (breath holds) beyond two minutes. My goal would be four minutes for static, and my dynamic apnea (swimming under water) to further than 40m, maybe to as much as 100m but I don't know what the reality of that would be.
I'll set some more realistic goals in between.
Labels: apnea, freediving
