Tag Archives: The Claw

Understanding The Claw as a hypothermia indicator

The Claw isn’t a fist. With The Claw, all fine motor control is lost and the fingers spread apart, and the swimmer in unable to close them. Remember I’ve said previously that there were no muscles in the fingers? The tendons contract due to impaired peripheral blood flow and the fingers bend slightly, like a person imitating a cat’s claw-strike.

Donal’s Claw, seen underwater

For those used to cold water, appearance of the Claw is normal, and only experience by the swimmer can track its progression from the initial barely noticeable slight weakness in the little finger, who spreads out ever so slightly from the ring finger, so slight you may not notice it has moved mild to the state at which it indicates immediate water evacuation is required, where are fingers are spread and the best will in the world won’t close them. However The Claw is not a useful external visible indicator for others, only the swimmer can accurately determine both its presence and extent.

Above, after a brief 5 minute swim at Cap Gris Nez in, CS&PF English Channel pilot Paul Foreman shows peripheral vaso-constriction in the hands,as seen by the extensive white, of an non-adapted person.

With worst case Claw, when I am in my most hypothermic state, I am still able to hold a feed bottle. Also, as experience progresses some swimmers, (including me) report the incidence of Claw decreases, but all other hypothermic warning signs are still relevant.

In fact, Extreme Dan Martin had a very interesting comment here on the linked piece above when I wrote it last year, such that is worth putting here as it adds an important piece to the overall cold puzzle:

I spoke to a hand and forearm surgeon on a swim camp in Jersey and she said that it’s due to the nerve running through your elbow. Apparently it’s one of the closest to the skin’s surface (it’s the reason why hitting your ‘funny bone’ hurts/numbs so much). She told me that when the nerve gets cold it jams on and this causes the muscles to contract causing the claw. I think it now being there when it’s very cold is that we’re not in long enough to chill the nerve down as other things pack in first!

This would have to be the Median Ulna Nerve (thanks Ryan!), which passes under the Carpal Tunnel (which when pressed on too much, causes Carpal Tunnel Syndrome).

(I was going to link a video of fingers being articulated by retraction of the tendons in an opened wrist, but decided graphic surgical video content may not be your thing).

I say all this because I think it’s important to be accurate about cold and not rely too closely on formulaic solutions or warnings. Understanding is better than rote.

Where did my Claw go? (loneswimmer.com)