Sleep Hygiene & Zeitgebers Flashcards
KKDP 6
Zeitgebers
Zeitgebers are external or en ronmental time cues that influence circadian rhythm
● Zeitgebers in the external en ronment are used by the SCN to adjust circadian rhythms to a 24-hour day. The SCN is believed to do this on a daily basis.
● When the SCN adjusts or resets the sleep–wake cycle to match the en ronmental day–night cycle through the influence of a zeitgeber, the circadian rhythm is said to be entrained, and the process is called entrainment
Zeitgeber: Light
Light can affect sleep both directly; by making it difficult for people to fall asleep, and indirectly; by influencing the timing of SCN acti ty and consequently our preferred time to sleep.
Daylight:
When exposed to the natural light from the sun in the course of a typical day, the circadian sleep–wake cycle becomes closely synchronised with sunrise and sunset, keeping an indi dual awake during the day and sleeping when it’s dark.
● Exposure to daylight during the morning hours and early a ernoon advances the sleep–wake cycle, pushing it forward to a slightly earlier time.
● Light exposure in the late a ernoon and early evening has the opposite effect, delaying the sleep–wake cycle and pushing it back to a later time.
Bluelight
Most of the exposure to blue light comes from the sun It’s a portion of the sible ➡
light spectrum emitted by the sun and plays an important role in the timing of the sleep–wake cycle and preparing for sleep a er the sun sets.
↳ Too much exposure to blue light in the evening disrupts circadian rhythms lea ng a person feeling alert instead of drowsy and ready for sleep
Blue light is also emitted by LED and fluorescent lights, as well as electronic back-lit de ces, e.g: mobile phones, tablets, computer screens, e-readers, TVs
● Exposure to the low intensity blue light from these de ces and household lighting in the evening affects circadian rhythm in the same way as bluelight does from the sun
Blue Light Effects on Sleep Quality & Quantity:
Blue light in the evening can also affect sleep quality and quantity.
● Prolong sleep onset
● Shorten total sleep time
● Reduce the amount of time spent in NREM deep sleep and REM sleep
● Increase the frequency of night-time awakenings
● Cause morning sleepiness, especially when awakening
● Even a quick glance at an LED screen emitting blue light to check the time or a
message can disturb the sleep phase and contribute to poor sleep.
So, In the hour or so before bed, exposure to blue light should be minimised.
● Blue light also helps keep an indi dual alert by suppressing the secretion of melatonin
● As with daylight, properly-timed exposure to blue light can be used to improve sleep–wake patterns and mental wellbeing.
Zeitgeber: Temperature
Sleep is most likely to occur when core body temperature decreases, and much less likely to occur during the rise when the body is preparing for wakefulness.
Generally, about two hours before falling asleep, the core body temperature starts to decrease under circadian control, coinciding with the secretion of melatonin.
↳ E vidence suggests that a temperature of around 18° celsius is best for sleep.
Zeitgeber: Eating & Drinking Patterns
Eating and drinking patterns refer to what, when, and how much food and drink is consumed by an indi dual. Eating and drinking patterns are considered a zeitgeber because they can impact the quality and quantity of our sleep.
● Erratic eating and drinking patterns with highly variable times when meals and snacks are consumed that also vary from day to day have been found to have detrimental effects on the sleep–wake cycle.
what?
● The types of food and drink an indi vidual consumes can influence the quality and quantity of sleep; some foods can negatively impact sleep and some can positively impact sleep.
● Some of the foods and drinks that can impact the quality and quantity of sleep include: caffeine, alcohol, spicy foods, high-sugar and high-fat foods.
when?
● Eating too close to sleep time can make it harder to fall asleep.
● Eating food close to sleep time can impair an indi vidual’s quality
and quantity of sleep, due to the stimulation of the digestive system
how much?
● Specifically, going to sleep feeling hungry can lead to poorer sleep quality and quantity.
● Additionally, eating large meals close to sleep time and going to sleep overly full can impair sleep patterns.
Improving Sleep Hygiene:
Sleep hygiene involves practices that tend to improve and maintain good sleep and full daytime alertness.
● Includes beha ours and en ronmental factors that can be adjusted to help with a good night’s sleep.
● Can be both appropriate (supports good sleep) or inappropriate (inhibit good sleep).
○ Inappropriate sleep hygiene practices do not necessarily cause sleep disturbances in all people.
Good Sleep Hygiene Practices
● Establish regular and relaxing bedtime routines and maintain a regular sleep-wake cycle.
● Associate bed and bedroom with sleep (no phone, TV or study).
● Avoid stimulating acti ties in the hours before bed.
● Eat at least two hours before bed.
● When you cannot sleep, get up.
● Avoid napping during normal waking periods.
● Avoid stimulants such as caffeine, nicotine and alcohol too close to bedtime.
● Regular exercise (for at least 20 minutes) during the day.
● Improve sleep en ronment (eg: ensuring the room is at the right temperature).
● Ensure adequate exposure to natural light.
