Tag Archives: alert

Are you an Owl or Lark?

An ‘Owl’ is someone whose body clock is set to sleep later than average, and a ‘Lark’ is someone whose set to sleep earlier than average. It is your inherent melatonin rhythm and temperature rhythm that determine when you sleep.

Being an Owl or Lark can impact how well you do with different schedules. Generally speaking, Owls do better with later schedules and shift work like graveyard. Larks are the ones you’d want to open the shop in the morning. It’s important to know that alertness fluctuates over the 24 hours in almost the same curve as temperature. As your temperature drops you are less alert and more sleepy.   If you get into bed and try to sleep before your body is ready, you may experience this as insomnia.  About 10% of chronic insomniacs actually are Owls, and if they go to bed later have no problem sleeping.

To determine if you are an Owl or Lark you can do the Horne-Ostberg Morningness-Eveningness questionnaire, which was developed in 1976. You can find a modified version of it online at http://web.ukonline.co.uk/bjlogie/test.htm.

This information can help you develop a lifestyle that best suits your circadian rhythm.  If you are not able to shift the time of your commitments, a sleep specialist may be able to help shift your circadian rhythm.

Are Naps Healthy?

I get this question all the time from patients who ask “what about naps?” Let me give you a little information about naps and night time sleep. Another day we’ll look at the effect of naps on alertness and performance.

There are several things to know before deciding to take a nap or not. First of all, from the time we wake until the time we go to bed our sleep drive increases. This sleep drive helps us fall asleep easily. When a nap is taken, it decreases our sleep drive back to zero, and there is less time than normal until bedtime, so at bedtime our sleep drive is less than normal. This can result in difficulty falling asleep, or in a short sleep duration.

The second thing to understand is the sleep cycle. There are four stages of sleep – REM, and NonREM stages 1, 2, and 3. Stage 3 is considered “deep” sleep, and is the most difficult to wake up from. We cycle through all these stages every 90-120 minutes. So a short nap of 30 minutes, or a longer nap of an hour and a half is best. This helps avoid waking out of stage 3 sleep and feeling groggy.

So overall, if you are going to take a nap, take it earlier in the day so that your sleep drive has time to build up again before bedtime and help you fall asleep easily. Also time your nap for less than 30, or more than 90 minutes so that you can wake feeling alert, not groggy.