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Can you “train” your fingers and toes to withstand cold?

November 28th, 2011

Winter’s coming, so here’s a topical study just published in the European Journal of Applied Physiology. Do your fingers and toes gradually adapt to being exposed to cold temperatures? There are three questions we can ask:

  1. Are the digits able to maintain a higher temperature when they’re exposed to cold?
  2. Are the digits quicker to experience “cold-induced vasodilation” (COVD)? (When you get cold, your blood vessels contract; but after a certain point, the vessel walls get so cold that they can’t stay contracted, so you get a sudden rush of blood that helps to warm up your fingers and toes — which turns out to be a very useful response to avoid frostbite.)
  3. Do your digits hurt less?

Over the years, many researchers have tested whether our digits adapt to cold, and the results are all over the map — some see a positive effect, some see a negative effect, some see no effect. Into the breach come researchers from the Netherlands and from Brock University in Canada. They took 16 suckers volunteers and had them dip their right hand and foot in 8 C water for 30 minutes at a time for 15 consecutive days. At the beginning and end of the experiment, the “trained” hand/foot was compared to the “untrained” hand/foot.

Here’s how skin temperature changed over the 15 days:

The data kind of meanders around, but there’s not much of a clear trend. Unfortunately, there was a clear trend for CIVD: during the pre-training test, 52% of subjects experienced CIVD; during the post-training test, only 24% experienced it.

And finally, the pain score:

On the surface, this might seem like good news: it hurts less as you gradually become accustomed to the unpleasant sensation of being cold. In fact, though, this is bad news. As your body gets used to the cold, you notice it less, but you also are less likely to get the warming effects of CIVD. Combine these two factors, and you become increasingly likely to get frostbite without realizing it.

So what does this mean? Well, it probably ends my dreams of being a polar explorer. I have extremely poor circulation in my fingers, and this suggests that this is unlikely to improve no matter how often I freeze my fingers off. So, despite the odd looks I get, I’m going to continue to run in my big puffy mittens whenever it gets close to freezing, because I won’t get any long-term “training” benefit from suffering.

  1. November 28th, 2011 at 03:25 | #1

    Related … http://www.youtube.com/watch?v=madoDvtKEes&feature=player_embedded

    And you need email subscribe to your comments (beyond the RSS subscription to comments).

  2. Juha
    November 28th, 2011 at 06:12 | #2

    It is in the brain. You teach the right hand and the left learns too.

  3. alex
    November 28th, 2011 at 13:36 | #3

    @George: Ugh, that’s wild! Reminds me a bit of Lewis Pugh, who also demonstrated the ability to raise his own core temperature (his core temperature would start rising BEFORE his cold-water swims, as measured by Tim Noakes). Suffice to say, these appear to be fairly unusual abilities!

  4. alex
    November 28th, 2011 at 13:38 | #4

    @George: Oh, and re. e-mail comments — yes, that’s a good idea. I’m overdue on updating my blog template, but I’ll look into it, hopefully sometime before the end of the year!

  5. November 28th, 2011 at 15:32 | #5

    Other adaptations may be possible on a longer time horizon, you’ll just need to spend a few seasons on a fishing trawler to realize them: http://jap.physiology.org/content/15/6/1031.abstract

  6. alex
    November 28th, 2011 at 15:44 | #6

    @Craig: Good point about the time frame — 15 days is pretty short. There have been other studies suggesting adaptation too; here’s a quote from the discussion section of the paper I just blogged about:

    “These studies showed that natives of circumpolar environments (e.g., Inuits and Sami) exhibit a higher mean finger temperature compared to people who live in a more temperate climate when exposed to cold. An enhanced CIVD reaction was also observed in fishermen compared to a control group less regularly exposed to cold. Nelms and Soper (1962) found that fish filleters, who are exposed to local cold only, also showed a significant earlier CIVD reaction compared to the control group. However, the possibility of self-selection for these particular occupations should not be excluded.

  7. Chris Pella
    December 1st, 2011 at 19:15 | #7

    Anectodally, any serious cross-country skier will tell you they are much more tolerant of the cold at the end of a season. A ski in December that requires thick gloves requires thin ones or nothing at all by late March, at the same temperature.

  8. alex
    December 1st, 2011 at 19:53 | #8

    @Chris: Agreed, and the same is true for runners. And this study support that idea to the extent that “perceived pain” definitely drops with acclimatization. What didn’t really change (at least not significantly) is skin temperature and blood circulation. So it’s not that your body gets better at keeping your extremities warm — it’s just that you get used to the pain. In most cases (i.e. skiing and running in cold but “moderate” conditions), that’s great — we’re mainly interested in minimizing discomfort. But in colder conditions or in more extended exposure, this is bad news, because it makes you less likely to even realize that you’re in danger of frostbite.

  9. Craig N.
    December 3rd, 2011 at 17:54 | #9

    As a surfer who surfed many winters in NJ’s waters – even before great advances in wetsuit technology – I can attest to increased whole body cold tolerance (and pain tolerance) building as one’s exposure experience increases. And the results on myself (and apparent in others sharing the experience(s) with me) the digits worked better as the whole body became better accustomed to the extremes. WIth that as my background, I have to discount a study designed to test a situation that is inlikely in real life; only one body part experiencing cold. The human body is capable of adaptation as a whole and digits are not independent of the whole.

    Along those lines I once was told of a grim study done by Himler in World War II where he took captured Russian solders and put them in cold tanks. I recall they lived many more hours than other less adaptive prisoners. I’m confident this adaptaion included their toes and fingers.

  1. December 1st, 2011 at 14:41 | #1
  2. December 2nd, 2011 at 02:24 | #2
  3. December 4th, 2011 at 17:33 | #3