Heated vests

[lexvil]

A heated vest or heated undergarment is 100% a luxury item and certainly for everyone, but I have to say it's REALLY nice. Yes, thicker undergarments are cheaper, but that would also mean extra led, which I would be hauling up and down steps, sometimes through a park or across a street, across a sandy beach, entering and exiting surf, and swimming it out to the dive site. Those extra pounds make a massive difference at the end of a long dive when I'm exiting through surf and hiking up stairs or a ramp. This is a thinner option.

For me, a heated vest isn't meant to replace a drysuit or insulation, but to add comfort and extend bottom time, without adding a lot of led. In the winter, I'm mostly diving 55-57 degree water with a drysuit. Without the heated vest this would be fine if my dives were only 50-70 minutes. I could even dive wet for 60 minutes and be fine. However, my bottom times are typically 80-100 minutes, not counting the 10+ minute swim out to the site, at which point I get cold. Heated vest solves this issue for me, and as mentioned, it's kind of luxurious to solve this withOUT adding a lot of bulk and led. I'm not doing multiple dives a day like I used to, but if I were, I could see it being massively helpful to maintaining core warmth.

Had one, sold it for very little, you’ll be warmer with better undergarments. I mostly didn’t like the 3 lb of battery so far up toward my head. Everyone gets to make their own choices.

 

[livewire]

Someone once told me that diving was meant to be enjoyed, not endured. Cant speak for others experiences, but for me personally this heated vest is helping me do that.

 

[34109411]

Someone once told me that diving was meant to be enjoyed, not endured. Cant speak for others experiences, but for me personally this heated vest is helping me do that.

i am sure it does if i could find where i will send the link i read heated vest could contribute to DCS..let me check if i find it... Body warming too fast from cold to warm...increasing of bubble formation.(Simon Mitchell, if i recall..)

 

[livewire]

i am sure it does if i could find where i could send the link i read heated vest could contribute to DCS..let me check if i find it... Body warming too fast from cold to warm...increasing of bubble formation.(Simon Mitchell, if i recall..)

Were there any documented cases of DCS caused by heated vests or heated undergarments? I'd be curious about the contributing factors, and if these were technical divers on planned deco dives, recreational divers on multiple dives or other details.

Might be getting off topic, and not that we need to go down the rathole of bubble formation, but in general, your inert gas load here is the big factor. If you have a smaller inert gas load, warming helps out because your circulation and blood flow help eliminate inert gases. If you have a larger inert gas load (say from deeper/lengthier deco dives), then you face more complications. Warming up tissues that have significant gas loads dissolved in them can promote bubble formation, which is obviously bad, but it's not quite as simple as saying you shouldn't warm up after a cold dive where you spent time making a deco stop. There are a lot of variables in this equation.

One other theory would be that being warm during a dive also allows more blood flow, which would make your body more efficient at on-gassing during the dive, causing a greater load, and then getting out of the water and warming up more could contribute to bubble formation.

Still though, too many variables, so I think you have to look at the data associated to documented cases.

 

[34109411]

Were there any documented cases of DCS caused by heated vests or heated undergarments? I'd be curious about the contributing factors, and if these were technical divers on planned deco dives, recreational divers on multiple dives or other details.

Might be getting off topic, and not that we need to go down the rathole of bubble formation, but in general, your inert gas load here is the big factor. If you have a smaller inert gas load, warming helps out because your circulation and blood flow help eliminate inert gases. If you have a larger inert gas load (say from deeper/lengthier deco dives), then you face more complications. Warming up tissues that have significant gas loads dissolved in them can promote bubble formation, which is obviously bad, but it's not quite as simple as saying you shouldn't warm up after a cold dive where you spent time making a deco stop. There are a lot of variables in this equation.

One other theory would be that being warm during a dive also allows more blood flow, which would make your body more efficient at on-gassing during the dive, causing a greater load, and then getting out of the water and warming up more could contribute to bubble formation.

Still though, too many variables, so I think you have to look at the data associated to documented cases.

Were there any documented cases of DCS caused by heated vests or heated undergarments? I'd be curious about the contributing factors, and if these were technical divers on planned deco dives, recreational divers on multiple dives or other details.

Might be getting off topic, and not that we need to go down the rathole of bubble formation, but in general, your inert gas load here is the big factor. If you have a smaller inert gas load, warming helps out because your circulation and blood flow help eliminate inert gases. If you have a larger inert gas load (say from deeper/lengthier deco dives), then you face more complications. Warming up tissues that have significant gas loads dissolved in them can promote bubble formation, which is obviously bad, but it's not quite as simple as saying you shouldn't warm up after a cold dive where you spent time making a deco stop. There are a lot of variables in this equation.

One other theory would be that being warm during a dive also allows more blood flow, which would make your body more efficient at on-gassing during the dive, causing a greater load, and then getting out of the water and warming up more could contribute to bubble formation.

Still though, too many variables, so I think you have to look at the data associated to documented cases.

like i said i need to double check ! i am not making my own statement.

 

[livewire]

Did some google searching on risk of DCS and DAN has a few articles posted, which I've shared below. In short, their advice is to run low or no heat while you're on-gassing (deeper part of the dive), and feel free to get comfortably warm while you're off-gassing (ascent and stops). Makes sense... colder tissues absorb less gas, warmer tissues will on-gas/off-gas more efficiently, and you don't want to on-gas super efficiently and off-gas poorly. Details below:

DAN posted an article on heated garments in 2022, where they reference a study conducted in 2007 at the Navy Experimental Diving Unit on the thermal impact on decompression:

Heated Garments

In a separate article on the DAN web site on medical considerations for dry suit diving, they state the following:

"Some divers choose to wear electrically heated garments for added thermal protection. Such garments may enhance your underwater comfort; but, if not used properly, they can increase your risk of decompression sickness (DCS). To minimize decompression stress, leave heated garments off or at the lowest setting during the descent and bottom phase to minimize the increase in inert gas uptake, then increase the setting modestly for the ascent and stop phase to encourage inert gas elimination without excessive promotion of localized overheating that can promote bubble formation and skin symptoms."

In an article found on the DAN South Africa web site on factors that increase risk of DCS:

A diver’s body temperature can influence decompression risk. A warmer body absorbs more inert gas and releases it more readily. Conversely, a cooler body absorbs less gas during descent and releases less during ascent.

Divers using protective suits without active heating should avoid long exposure that may chill them toward the end of the dive. When using heated garments, a diver should stay comfortably cool at depth and warm during decompression. Staying comfortably warm during decompression and after dive promotes inert gas elimination and reduces the risk of DCS. However, attempt to quickly rewarm after dive, like taking hot shower or bath may provoke decompression illness.

 

[grantmac]

Biggest issue is having heat fail while under a significant deco obligation where it's possible to become hypothermic.

 

[Whitrzac]

Every case heard about/person I've talked to with a shorted vest knew there was an issue and chose to keep the heat on.

I know of one person that had the vest not turn on at the bottom, had a minor drysuit flood, and had a severe dcs hit because of hypothermia. They no longer dive.

 

[livewire]

In an effort to cite the best possible guidance for use, let's look at what we might have learned in this thread so far:

Between the case @Whitrzac cited and the navy tests cited by DAN, sounds like if there's no deco obligation, then there is very little to worry about. DAN would say stay comfortably cool with on-gassing, and warm during off-gassing. In the event of heated garment failure, bail out before you go hypothermic. Most people would wear a heated garment with a wetsuit or dry suit, so this wouldn't usually constitute an emergency on a recreational dive with no deco required.

If you're doing a deco dive, however, as with all deco dives seems like we have extra considerations:
(1) Per DAN, stay comfortably cool while on-gassing, get warm while off-gassing
(2) Have contingency plans in the event of heated garment failure. Don't be solely dependent on your heated garment to get your through your full plan or bail-out plan.
(3) Ask yourself if you would go hypothermic if your heated garment failed, and work a plan to avoid that.
(4) Plan for a thermal emergency: contingency plan for the event of dry suit leak combined with heated garment failure.