Sleep hormone: Melatonin

Sleep hormone: Melatonin

When the sun goes down, your pineal gland
switches on like clockwork to secrete melatonin,
a hormone that helps you fall asleep
and regulates your circadian rhythm. It lowers
your core body temperature, which if too
high promotes wakefulness. Production of
melatonin peaks in the middle of the night,
and the process can be disrupted by even
very low levels of artifi cial light.
Are your hormones in tune? Mounting evidence
suggests that exposure to light at
night—whether you’re asleep or awake—
might play a crucial role in cancer, diabetes,
and obesity. The World Health Organization
classifi ed “circadian disruption” as probably
carcinogenic, and light at night is considered
by some to be an endocrine disruptor
that may aff ect melatonin, cortisol, ghrelin,
leptin, and testosterone. “Most people
think, and the drug companies want you to
think, that waking up at night is bad for
you,” says Richard Stevens, Ph.D., a cancer
epidemiologist at the University of Connecticut
health center. But that’s not the
case, he says—it’s exposure to light at night
that’s the problem. “If you wake up at night,
as most of us do, that is a period of quiet
wakefulness—stay in bed, in the dark, and
enjoy it,” Stevens suggests.
You don’t have to be asleep to have good
melatonin rhythm, but you do need to be in
the dark. Buy heavy curtains, cover your
alarm clock, and turn off gadgets. “Make it
dark enough that you can’t see your hand,”
Stevens says. “If you go to the bathroom and
turn on that bright light, you’ll lower melatonin
almost immediately,” says Stevens. “I
actually have a red night-light in my bathroom,
because red light has less eff ect on melatonin
than white or blue light,” he says.