Photo: Getty Images

Even if you manage to cover the dark circles under your eyes and get the red out, your hair may be a dead giveaway that you've been burning the midnight oil.

Sleep is the body's natural restoration period, the time when it rejuvenates and repairs itself. When this suffers, our hair can too. Without enough shut-eye, our tresses simply won't grow as thick or as fast, and they will often lose their shine and bounce.

Worse than lackluster hair is losing it altogether.

According to a leading hair loss clinic in Britain, The Belgravia Centre, a lack of sleep has been shown to affect the body's immune function, hormone secretion, and physical and mental stamina. "Hair is very sensitive to changes within the body, and hair loss is nearly always the consequence of an internal disturbance," they state on their web site.

That internal disturbance is often stress -- something that goes hand and hand with sleep deprivation.

While some people can get enough sleep in just a few hours each night, others need a full eight or nine hours to feel fully rested. Either way, if the normal sleep pattern is disrupted, it can trigger emotional and physical stress.

Senior trichologist at the Belgravia Centre, Leonora Doclis, says, "Sleep deprivation is a form of stress, a terrible form of stress."

Doclis goes on to state, "Stress can indeed cause hair loss. In those susceptible to male pattern baldness or female pattern hair loss, stress can instigate, accelerate and aggravate the problem."

In addition to getting enough zzz's, you can pamper your slumbering strands with a nighttime masque or leave-in conditioner. John Frieda's Frizz-Ease Creme Overnight Repair and L'Oreal Professionnel's Liss Ultime Nuit are two good options.

You can also treat your tresses to a silk or satin pillowcase. Besides feeling delightfully soft, the smooth surface creates less friction so it's easier on your locks when you toss and turn. This can not only help prevent hair loss and breakage overnight, it can also keep your hairstyle in check -- possibly avoiding the dreaded bed head when you wake.

Want more ways to get great hair in bed? Check out these tips!