Bottoms of feet cold (drysuit, 39F / 3.9C water)

[formernuke]

I know the OP stated they fixed it...

But too much warmth can be cold as well. If your feet start to sweat and get the socks wet.
Learned that with drysuits really quick. The more I bundle up, the colder I got, because I was sweating too much, mostly on the surface. I need to stay ever so slightly chilled to stay dry and warm.

I have that problem sometimes in my feet. Feet sweat and get cold as a result

 

[BlueTrin]

If you want to be warm you need to have room in there, have proper boots put on and go up a size.

I may consider this later if I get cold but the ocean isn’t that cold where I live and I don’t do more than two 1 hour dives at my level in a day.

I have that problem sometimes in my feet. Feet sweat and get cold as a result

What socks do you use? I use wool socks (or part wool) made for trekking, they are quite good at wicking the sweat.

 

[formernuke]

I may consider this later if I get cold but the ocean isn’t that cold where I live and I don’t do more than two 1 hour dives at my level in a day.



What socks do you use? I use wool socks (or part wool) made for trekking, they are quite good at wicking the sweat.

Yup wool socks under my undergarment socks, learned the hard way.

 

[BlueTrin]

Yup wool socks under my undergarment socks, learned the hard way.

You must be doing much colder (or longer) dives than I do: I use only one layer

 

[Stoo]

I have that problem sometimes in my feet. Feet sweat and get cold as a result

Wear Smartwool or similar. Dry suit underwear "booties" that are both lined and covered with nylon don't breath at all. Thick wool socks wick and stay warm.

 

[formernuke]

Wear Smartwool or similar. Dry suit underwear "booties" that are both lined and covered with nylon don't breath at all. Thick wool socks wick and stay warm.

See later post, I started doing just that

 

[Subcooled]

See later post, I started doing just that

Wool is important. We have known this in drysuit diving since the 17th century.

19th century diving dress undergarments:

 

[MattK911]

Second, consider some toe warmers. They have a self-adhesive patch on the bottom. Stick them outside your socks (or between two socks) but not on your skin. I use the equivalent in my gloves as well.

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This is a terrible idea and I feel like it should be addressed. For anyone who doesn’t know these heating packs work through oxidation, meaning they are essentially oxygen activated. As such, exposing these warmers to elevated partial pressures of oxygen seen inside of a drysuit at depth is a good way to get burnt. About 20 years ago there was a lawsuit against a hot hands manufacturer where exactly this had happened. A diver was doing a sub 100ft dive and inflating his suit with 32% Nitrox, and ended up being hospitalized for his burns. I will try to find the case file, I have it laying around somewhere.

 

[Stoo]

This is a terrible idea and I feel like it should be addressed. For anyone who doesn’t know these heating packs work through oxidation, meaning they are essentially oxygen activated. As such, exposing these warmers to elevated partial pressures of oxygen seen inside of a drysuit at depth is a good way to get burnt. About 20 years ago there was a lawsuit against a hot hands manufacturer where exactly this had happened. A diver was doing a sub 100ft dive and inflating his suit with 32% Nitrox, and ended up being hospitalized for his burns. I will try to find the case file, I have it laying around somewhere.

Ya ya.... we all use them on literally every dive... well hand warmers, toes less often. Never on bare skin...

The case you are referring to involved a UK diver, who used a 6" x 8" torso pad stuck directly to his lower back. I don't know what gas he inflated his suit with, but I suspect it was something a lot hotter than 32%

I see you're in GA, so truly cold water may not be something you're exposed to, but I assure you, in these parts, these things are in common use and quite helpful. At best they get "quite warm" but even with nitrox, they're far from a temperature that would cause any degree of burn on bare skin. The reality is that in gloves and boots, there's so little gas flow (which is part of the reason hands and feet get cold.) that these heat packes never really get above "idle". I will add that I don't use wrist seals at all so that I can increase air flow to my hands. Even doing that, these things are comfortably warm and no more.

 

[RedSeaDiver2]

Feet get cold for two reasons (three if you count misc medical things like reynaud's). Cold core (body moves heat towards things it wants to protect) or poor circulation (body can't put warmth in places blood isn't actively going in and out of).

I do think there's a point in warmth/duration where safety increases for a slightly heavier suit gas:wing ratio and you're about there.

Your options, assuming you're already optimizing caloric intake, pre dive ritual, etc, (imo) in order of decreasing value per warmth unit, include:

-FE XCore vest or similar
-12+ mm Otter Bay custom hood (get one of these)
-Heated vest
-Heated socks+gloves
-Heated BZ400x
-Neo suit
-CCR (warmer gas)

At a certain point in sub 40 degree water (and with deco), there's little choice but to add external heat. You're also approaching exceedingly poor offgassing, especially in times of year without thermocline.

Here's a draft of a External Heat Wiki, that eventually @rjack321 (who like me spends too much time in cold water) and @tbone1004 (engineering/ocd/textile understanding) will be asked to edit

Did you ever get to the -
Topics to be continued:
Other garments
Socks
Gloves