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Mammalian dive response in action, collection of HR/DEPTH/TIME graphs on real ocean dives

cdavis

Well-Known Member
Jan 21, 2003
3,961
749
218
70
Sarasota, Fla
Thanks Lance, Very interesting stuff.

In your exhale dives, I see some spiky inceases in HR on ascent. Diving half lung, I don't seem to get that. Is that a function of your greater exertion than my tropical stuff? or maybe something else?

in your blog, dive #7 looks very much like a lot of what I do. The few times I've worn an heart rate monitor, it looks like your graph if I'm doing it like i should.
 
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growingupninja
Mar 20, 2011
704
150
83
Los Angeles
Thanks Lance, Very interesting stuff.

In your exhale dives, I see some spiky inceases in HR on ascent. Diving half lung, I don't seem to get that. Is that a function of your greater exertion than my tropical stuff? or maybe something else?

in your blog, dive #7 looks very much like a lot of what I do. The few times I've worn an heart rate monitor, it looks like your graph if I'm doing it like i should.
I definitely work way harder on ascent in a 5mm suit with my regular dive lead than you would skin diving in the tropics. But also the spiky increases also could be my own system. I purposely kept the filtering of heart rate very, very minimal. In my experience most HR monitors filter out those kind of aryhthmias and sharp spikes as (presumably) noise; when I wear my fingertip pulse oximeter, which has a pretty solid HR detection, the reported rate is always smoother than what I get out of my own programming with the polar strap.

Murat postulated that ascent tachycardia was not a great sign and I'm inclined to agree. His theory was that BO could be predicted that way that divers who exhibited a lot of ascent tachycardia were more prone to BO. In all my graphs I tend to get spikes during difficult portions of my ascent but dive response then overcomes and mutes the spikes. The dives that I felt subjectively best on, before reviewing data, also tended to have more smooth curves on ascent and frequently descent. However, there are certainly drops where I'm mentally rather freaked out during the dive but showing steady low HR when I look at the graph after the fact.
 
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growingupninja
Mar 20, 2011
704
150
83
Los Angeles
I am in Hawaii, getting ready for a depth comp. I wore my monitor yesterday in training, doing some of the exact same dives but here in warmer water with a thinner wetsuit.

Need to get back home to get to my graphing software but from glancing at the results, it is interesting to see the differences. Less pronounced bradycardia across the board but overall slower increase in HR on ascent than the California dives. I will put up a few next week.

Sent from my SM-G930T using Tapatalk
 

Fitz-Clarke

Well-Known Member
Dec 9, 2004
63
26
98
Halifax, Canada
Your device has potential for some interesting research. The spikes could be due to ectopic beats, such as PACs and PVCs, which are known to occur with greater frequency during ascent, and seem possibly consistent with your results. Does your device record all individual interbeat intervals, or is there some kind of running averaging over multiple beats? I'm also wondering if it could be adapted to record ECGs. That would require continuous sampling of mV signals using medical grade electrodes. It would resolve ectopic beats and improve the quality of your data.
 
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growingupninja
Mar 20, 2011
704
150
83
Los Angeles
Your device has potential for some interesting research. The spikes could be due to ectopic beats, such as PACs and PVCs, which are known to occur with greater frequency during ascent, and seem possibly consistent with your results. Does your device record all individual interbeat intervals, or is there some kind of running averaging over multiple beats? I'm also wondering if it could be adapted to record ECGs. That would require continuous sampling of mV signals using medical grade electrodes. It would resolve ectopic beats and improve the quality of your data.
Yes, it records the timing between individual beats and keeps a running count of total beats. What is presented in the graphs has very minor smoothing, the rounded whole number average of the last 3 beats.

I think the limiting factor is the waterproof and depth ability of the sensors. This doodad is sealed and only recieves signals either via bluetooth (doesnt work underwater and not implimented in the software I wrote) or a Polar reciever that can read signals from Polar chest strap underwater. The limit is that the strap only sends a signal when it detects a beat, so it is very binary and limited by what the chest strap interprets. An EKG would be nice, if I had the sensors and specs I would just build another unit for that.

I have been in Kona (warm tropical water) and training for the last week. It is very illuminating to see how the dives compare to cold water, heavy wetsuit dives. I wore it on a 75M CNF attempt on Saturday that ended in BO as surfacing. Pretty cool to have that data and when you look at what the heart is doing prior to the dive and during descent, compared to other clean dives, it is obvious that the dive wont end clean. Ascent wasn't bad on that one, fairly ordinary tachycardia towards the end but accidental hyperventilation prior to the dive totally wrecked the entire descent. When I get back LA I am going to graph the data...

Sent from my SM-G930T using Tapatalk
 
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