I heard on the radio today that apparently a woman's hands are colder than a man's hands, but her heart is warmer. I didn't really believe this, but they stated that it was apparently scientifically proven, and what really astounded me was that they actually stated the margin: a woman's hands are 2.4°C colder than a man's, and her heart is 0.4°C warmer. Is there any evidence proving or disproving this?
The study the radio is talking about might be this one:
Physician Han Kim and his colleagues surveyed 219 men and women, from babies to octogenarians, and measured the temperatures in their ears and on their fingernails, which they took to be measures of core and hand temperature, respectively.
They reported that for women:
core temperature was on average 0.4 degrees higher than for men (97.8 degrees instead of 97.4 degrees).
But hand temperature was 2.8 degrees lower than for men (87.2 degrees instead of 90.0 degrees).
This study did a "Comparison of thermoregulatory responses between men and women immersed in cold water":
They found that the rate at which rectal temperature dropped was related to peoples' body fat as well as their surface-area-to-volume ratio.
People who are smaller, as women on average are, tend to have higher surface-area-to-volume ratios, which means they're likely to lose heat and to experience drops in core temperature more quickly.
Still, if a man and woman were matched for both measures, they should have the same response to cold, says researcher Peter Tikuisis.
more reading material:
Here is an interesting quote which may support the claim. From the article Why do women always feel colder than men?:
Mark Newton, a scientist at W.L. Gore, the company that makes Gore-Tex, and a researcher at the University of Portsmouth, explains: 'Women have a more evenly distributed fat layer and can pull all their blood back to their core organs.'
However, this female heating system means that less blood flows to their hands and feet, and as a result they feel cold. So there is literal truth in the old saying cold hands, warm heart. One theory as to why women have evolved this system, says Newton, is to enable them to survive freezing temperatures. Women carry less fat and muscle mass than men, and so need a more efficient technique of protecting their core body temperature.
I have just found an article from 2011 where this suggestion is reinforced by the same Mark Newton, who is now a Professor Mark Newton. So hopefully that will suffice.
There was also a quilt that was sold in Australia a few years back (I can't source it now). Where the women's side was actually made from warmer material than the men's half of the quilt.