How does humidity affect a man's hair?

Having a bad hair day? Blame it on the weather! Whether your hair is usually wavy, curly or straight, the humidity in the air can have quite a dampening effect on the way it looks and behaves -- regardless of gender.

Hair changes length with increases in humidity, so curly hair frizzes and straight hair goes limp. When moisture content in the air increases, hair length can change by up to 3 percent [source: Exploratorium].

In fact, human hair is so sensitive to humidity that meteorologists rely on strands of hair to measure moisture in the air using a device called a hygrometer. The hair is placed inside the hygrometer; the expansion and contraction of the hair then causes a spring to move a needle on a dial, providing a measure of humidity [source: Britannica].

Of course, dryness caused by low humidity or excessive blow-drying, can also wreak havoc on a man's hair, as it loses water that provides structural strength. The result is frizzy, brittle and damaged hair.

So, how does a well-coiffed guy cope? There are several products on the market designed to combat the effects of humidity. Shampoos, conditioners and styling creams help straighten hair that tends to curl or wave because they keep moisture from penetrating the strands by coating them with oils that keep hair from absorbing water. Other formulas claim to restore moisture to dry, damaged hair, again by coating the hair strands with oils. Electric straighteners work by pulling the moisture out of the hair, just as curling irons add curl by temporarily removing moisture and changing the shape of the hair. The effects are temporary, because once moisture works its way back into your hair, it will return to its original shape -- or to its natural tendency to curl or go flat.

For a more long-term solution, the best-tressed chap might consider a relaxer or perm. Relaxers use chemicals to break the disulfide bonds that make hair curly and cap them off so that they won't return to their original state. Perms use an oxidizer to increase the number of disulfide bonds in your hair so that it stays curly. With these treatments, men can use chemicals to shape hair into any style they want. However, perms and relaxers eventually "grow out" as your new hair grows in and replaces your treated hair with the hair type you were blessed with naturally. Too many of these treatments can be very damaging to your hair, making it thin and brittle.There's another tried-and-true solution if you've got long hair -- do as your female friends do and pull your mane back into a ponytail. Save the styling for a less humid day!