We each have an inner clock that influences when we feel like sleeping and waking and how tired we are. This clock in the brain tends to run slower than the 24-hour clock tied to the solar day — in fact, depending on genetics, it could be off by an hour or more. The inner, or circadian, clock controls the production of the hormone melatonin, which promotes sleepiness. When melatonin is delayed, you may suffer from insomnia. It also means the hormone may still be in your system when you want to start your day. This can cause fatigue and poor concentration, and leave you at risk for depression.
This quiz — a chronotype assessment — can help you find out how the clock in your brain measures up to the clock on the wall. It will provide feedback about your natural sleep cycle by estimating when your melatonin production begins. It will also tell you whether you might benefit from changing that cycle through chronotherapy — a regimen of exposing yourself to bright light at specific times.
Many night owls, who can’t fall asleep before 2 a.m. or even later, and struggle to make it into work, find that they can reset their inner clock by exposing themselves to light progressively earlier as they get up for the day. Falling asleep too early requires evening light exposure. Done properly, chronotherapy adjusts the timing of the release of melatonin, making it possible for patients to get to sleep at the time they want.
Skip the quiz if you: are a long-term night- shift worker; go to sleep before 8 p.m. or wake up later than noon; sleep for less than six hours a day without napping; or suffer from a chronic illness or use medications long-term that affect sleep or alertness.