Most annoying urban myths debunked – part 2

There are countless urban myths floating around. Some are amusing, some are terrifying and some are just plain weird. But there are also plenty of urban myths that I just find utterly annoying. Most of them are things I’ve believed in myself in the past, but when thinking about it logically realising couldn’t be true. Which is why I find them so annoying!

This is part two – you can read part 1 here.

3. You lose 90% of your body heat from your head

"If only I'd remembered to bring my hat - feel a bit stupid now"

Here’s one for us who live in colder climates: “Remember to wear a hat during winter as 90% of your body heat escape from your head.” I’ve always had a problem with this myth; it just didn’t seem to make sense. Why should almost all body heat escape from our heads? Even with the high level of blood circulating through our brains, it can’t really make up 90% of our body heat, surely?

No. It doesn’t. This is classic misunderstanding / misuse of statistics. The value 90% is correct, but we’ve taken it out of context. It should instead read as follows: ”If you don’t wear a hat, 90% of the heat escaping from your body will escape from your head, as this is the exposed part of your body.” And suddenly it makes sense! Whatever part of your body you expose to the cold will be responsible for the majority of your body’s heat loss. Obviously.

So wear your hat when you’re out in the cold - you would be stupid not to. Just don’t quote that old myth anymore. Please.

4. Shaving will make your hair grow back coarser

"Are these sideburns?! I better stop shaving before I grow a full beard!"

I don’t know why women favour this myth as much as they do: “I know waxing hurts, but if I shave, my hair will grow back stronger and coarser.” I assume that by this you mean that if you regularly were to shave your fine downy facial hair you’d soon have grown a full beard?

No. Shaving does not make your hair grow back coarser. Hair is not alive, it doesn’t know it has been shaven off. All the razor blade does is to cut off the part of the hair that sticks out of the follicle. The remaining hair stays behind to form the stubble, and this is what you can feel when touching your skin after shaving. The closer the shave the shorter the stubble, but as the hair grows back the stubble become more prominent. This is enhanced by the fact that the softer tips of the downy facial hair has been removed which expose the slightly thicker stem ending in a sharp cut. So your hair might feel coarser after shaving but it doesn’t actually become coarser.

Case in point: I’ve shaved (almost) every morning for 30 odd years. If this myth was true and hair did indeed grow back stronger I’d look like a mix between Santa Claus and ZZ Top by now. But it hasn’t and I don’t so it isn’t.

This is the second installment of the Urban myth series. You can find part 1 and part 3 here.