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59 Cards in this Set
- Front
- Back
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For people accustomed to sleeping at night, body temperature is highest at about ____ and lowest between ____ and _____.
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highest at about 8pm
lowest during sleep, between 3 to 5 am (though most of it persists even if a person remains awake) |
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What is the name of the process by which rhythm synchronization happens? (and how is this process causes)
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entrainment.
it is causes by zeitgebers, which are regularly occuring events EXTERNAL to the body. |
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What is the most important zeitgeber for humans?
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light following a period of darkness
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What are some examples of possible zeitgeibers?
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light following a period of darkness
warm days followed by cool nights daily variations in radiation levels social events such as mealtimes work and school schedules in some people, sleep-to-wake transitions appear to be important zeitgebers for entrainment |
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In the study where entrainment cues were withheld from a NY Times reporter, how much time did she spend asleep?
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30% (ranging from ~6hrs to ~11hrs per sleep period)
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What are some rhythms that became "uncoupled" in the experiment with the NY Times reporter?
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her body temperature (which cycled every 24 1/2) and her sleep/wake times (which was about 25 hours)
Also the rhythm of cortisole secretion became uncoupled. (It began to outpour several hours prior to sleep, rather than near the end of a sleep period as it is normally) |
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What happened to the NY Times reporter's REM sleep and SWS?
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the total amount of REM and its percent of the total sleep time remained unchange. Same with SWS.
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What happened to the NY Times reporter's REM/NREM cycle length?
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no change
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What are "nychthemerons"?
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They are 24 hour periods. The term is used to avoid the ambiguity inherent in the word "day." .. it is both night (nych) and day (themera)
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To what degree can zeitgebers be artificially manipulated to speed up or slow down a day until subjects stop following them?
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A day can be shortened (at max) to 23 hours or lengthened to 27 hours, maximum.
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Truck accidents involving no other vehicle are __ times more likely between midnight and 8 am.
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7
(there is an even greater peak between 3 and 6 am) |
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What surprising findings prominently revealed the "automatic behavior" state of nighttime truck drivers when scientists attached electrodes to record brain waves and eye blinks?
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They were surprised to see 20 minute periods or so of no eye blinks and sleep-like EEG.
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In a Swedish study, what % of nighttime train drivers fell asleep compared to daytime drivers durking a 341 km run?
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65% vs. "only" 13%
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What is the ratio of sleep to wake when one is put on a free-running sleep/wake cycle?
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It remains relatively constant at 30% sleep.
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The free-running SLEEP-WAKE CYCLE in females averages about _______ than in males while free running.
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averages about 1/2 hour less
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Females average more or less sleep than males when on a free-running cycle? By how much?
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They average about 18% more sleep.. (despite averaging shorter sleep-wake cycles)
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Is sleep extremely long when initiated at the peak or the nadir of nycthemeral body temperature?
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Sleep is extremely long when initiated at the peak of nycthemeral body temperature but is much shorter (and not too much different from normal sleep length) when sleep is initiated at the nadir of body temperature or when just beginning to rise.
Also, the termination of many sleep episodes occurs during the rise of body temperature regardless of the length of sleep. |
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Besides resulting in longer sleep when initiated at the peak of body temperature, how else does the circadian rhythm of our body temperature affect sleep?
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Sleep is much more likely to be INITIATED when body temp is getting close to or is at its nadir.
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The peak and slope of the rise in the circadian temperature cycle changes with the season. Does earlier peaking and more rapid rise occur in winter or summer?
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In summer. This leads to the speculation that it may not be possible to extend sleep as much in the summer as in winter.
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What is the Primary Sleepiness Zone?
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It is the longest and strongest period of sleepiness, beginning at about the typical bedtime and lasting several hours.
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What is the Secondary Sleepiness Zone?
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Occurs during mid-afternoon, is not as intense and lasts about two hours.
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What are Wake Maintenance Zones?
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They are two zones that occur each day that are also called the Forbidden Zones of Sleep. WMZ 1 begins a few hours prior to sleep and lasts for a couple of hours. WMZ 2 is weaker, and occurs for a few hour prior to the secondary sleepiness zone.
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What is an alternative conceptualization of the Sleepiness and Wake Maintenance Zones as postulated by Dave Dinges? (Include the probabilities of sleep onset and offset for each zone.)
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Divide the nychthemeron into four zones.
Zone 1: 1am to 7am Zone 2: 7 am to 1pm Zone 3: 1pm to 7pm Zone 4: 7pm to 1am Probability of Sleep Onset and Sleep Offset for Each Zone: Zone 1: High On, Low Off Zone 2: High Off, Low On Zone 3: High On, High Off Zone 4: Low On, Low Off |
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Which age group does not have a secondary sleepiness zone?
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Preadolescents. But they sleep more deeply during the primary sleepiness zone at night.
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How have the existence of four sleep zones been BEST demonstrated?
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These zones may be best demonstrated in experiments using ultra-short sleep-wake schedules (e.g. of 20 mins each: awake for 13 mins followed by 7 mins of opportunity to sleep for 24 or 36 hrs). When given such opportunity during a sleepiness zone, the subjects obtained much more sleep.
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What happens to sleep and wake maintenance zones when one is sleep deprived?
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The intensity of the zones are affected (WMZs are weakened and Sleep Zones are strengthened). Their timing is unaffected.
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Are most people evening or morning types?
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Trick question. Most are neither types.
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What (survey) evidence suggests that MTs sleep better?
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they have *SHORTER average SLEEP LATENCIES, are in a better mood upon rising, feel that they got an adequate amount of sleep, and feel *more mentally efficient. (upon rising or any time????)
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Do ETs obtain less sleep than MTs?
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No, though their sleep times may vary, on average they obtain the same amount of sleep as MTs.
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What differences, in terms of REM latency, do polysomnographic measures show between MTs and ETs?
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There is a SHORTER than average REM latency in MTS and a LONG REM latency in ETS. However, both are still within normal limits.
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How soon do ETs and MTs tend to fall asleep?
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ETs tend to fall asleep either quickly (within 10 minutes) or lie awake for a long time (30 or more minutes). MTs on the other hand show no such division and tend to fall asleep within 20 minutes.
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Are the physiological differences between MTs and ETs.
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None have been demonstrated.
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Are there performance differences between MTs and ETs?
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There is no consistent difference in actual performance between MTs and ETs a any time during the day. (really??)
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What piece of evidences suggests that your type may be a matter of habit, rather than genetics? And what evidence contradicts this.
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Workers are more likely to be MTs than students. (And people tend to become more and more like MTs as they get older, suggesting that people can and do change (but only as they get older???)).
However, the workers expressed a preference to be other than what they were, suggesting many more of them were going against a natural, inherited predisposition. |
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What correlation validates the use of certain paper and pencil tests in determining one's type?
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The correlation between the results of the tests and measures such as body temperature peaks.
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What are some effects of changing the time when you go to bed? (Name 5 that occur during sleep (during usu. wake time))
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Sleep attempted during usual waking hours results in
more arousals, less stage 2, less REM, shorter REM latency, and often shorter total time asleep. Also, performance during normal sleep time is greatly reduced, esp. for long, repetitive, and uninteresting tasks. More industrial accidents occur |
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What percent of flying accidents are attributed to pilot error?
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60%
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What are some symptoms of jet lag? (Name at least 5.)
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disorientation
fatigue decreased performance and concentration insomnia excessive sleepiness muscle aches disruption of appetite and digestion (think of the above average frequency of gastrointestinal disorders reported in flying airline personnel) |
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What is the cause of jet lag?
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Jet lag results from zeitgebers of the destination assaulting the body with info that is TOO DISCREPANT from its internal phase of circadian rhythms.
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How does travel of 10 or more hours to the north or south compare to a few hours to the east or west?
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Travel of 10 or more hours to the south or north does not produce jet lag, but travel of only a few hours to the east or west will.
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Is jet lag less prominent when traveling east or west? Why?
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There is less of an effect when traveling west, because this results in phase delay which is easier that phase advance, since our internal rhythm is longer than 24 hours.
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What % of people are minimally affected by jet lag an what % are highly susceptible?
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30% in both cases.
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At what age do people begin to become more susceptible to jet lag.
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After 40 years of age.
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What factors may lead one to be less susceptible to jet lag? (Name 4.) These are also factors of people who can better tolerate shift work.
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If one is an ET.
Extroverted personality. Non-insomnia. Being young. |
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What are several ways that jet lag can be combated. (Name at least 5.)
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1. Stay on HOME TIME if its a short trip over.
2. SYNCHRONIZE to your destination BEFORE YOUR TRIP by gradually phase delaying by 2 or 3 hours per day (or phase advancing 1 hour per day). *A popular technique used by athletic teams. 3. Use a jet lag DIET, involving eating carbs to induce sleepiness and protein to induce arousal. 4. Arrive Early to allow adjustments before enjoying your trip. 5. Synchronize quickly to the new environment. Avoid napping. Get out and be active and with other people during local waking hours. 6. Sleeping pills and stimulants (though some research suggests that they only delay jet lag effects and do not cure them) 7. Avoid alcohol or carbonated beverages on the plane (to avoid dehydration and abdomen swelling). 8. Bright light FOUR TIMES BRIGHTER than average can help shift circadian rhythms. 9. Melatonin. |
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What % of day workers report sleep problems? What percentage of shift workers report sleep problems?
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20% and 60% (40% more than day workers)
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What % of shift workers admit falling asleep on the job at least once a week?
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50%
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What % of shift workers admit to having fallen asleep to and from work in the last three months?
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15%
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Name some ways that shift work problems be alleviated? What is the minimum time one should stay on schedule before switching to a new one?
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By sticking to a constant schedule.
If rotation is necessary, then gradually rotating from days to evenings to nights to days is ideal. And NOT TO QUICKLY! (TEN DAYS on a shift is better, and three weeks is better yet.) Don't sleep right after work. Spend some leisure time. Avoid snacks. Eat on a regular schedule. Avoid overuse of caffeine. |
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How much did productivity increase in a study where workers were phase delayed to the next shift every third week (and were taught to gradually delay their sleep in anticipation of the next shift change)?
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Productivity improved by 20%
Job satisfaction much higher, and health of the employees increased. |
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Name some findings that suggest people are negatively affected by the phase advance that occurs in spring.
What about moving the clock back on hour in the fall? |
An 11% increase in traffic accidents the week after has been found.
People report awakening feeling more tense and more drowsy than usual during that week. A phase delay results in the opposite effects to some extent! |
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Does it matter if a person gets up at the same time each day? What about going to bed at the same time each day?
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A regular time of arousal appears to be the MOST IMPORTANT factor for keeping the many biological and physiological rhythms of the body in synchrony, which in turn results in people reporting feeling rested and good.
In regards to sleep initiation, ireggularity is not particularly harmful as long as a person does not continually push back the time of retiring and thus accumulate sleep deprivation. |
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Are people less regular about their times initiating sleep or arising?
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initiation of sleep is less regular
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In a survey about the need of an alarm clock, what % say they never use one? What % say they regularly awaken before their alarm goes off? What about those that SOMETIMES awaken before their alarm goes off? And what about those who say they NEED an alarm clock to awaken them?
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25% for each group. (So 3/4 say they awaken spontaneously at least some of the time, and half say they do so regularly)
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Is age correlated with the reported need for an alarm? How about consistent sleep times from day to day?
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The proportion of people who do not need to rely on an alarm increases with age and was SLIGHTLY greater in people whose sleep times are consistent from day to day.
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Describe a study where people were tested to see if people may consistently wake up without an alarm.
What was the difference between intended and actual arousal time? |
15 people were recruited who reported they could awaken from sleep without an alarm. They were asked to fill out a report before bed saying the time they wished to wake up, then report the time when they awaken. The subjects also wore actigraphs that indicated the subjects' active and still times. This was done for three nights.
All subjects did indeed awaken when they intended. The overall average difference between actual and intended arousal time was +4.61 minutes. (Apparently, and not related to the study, for some people this works even for very unusual times.) |
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How long are ultradian rhythms?
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less than a nychthemeron
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What is the basic-rest-activity-cycle (BRAC)?
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It's a theorized cycle that is really a continuance of the REM-NREM cycle (an ultradian rhythm) into wakefulness, though it may not be as obvious or stable as the NREM/REM cycle.
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What evidence is there for a basic-rest-activity-cycle?
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observations of alternating highs and lows about every 90 minutes in the performance of tasks requiring concentration, fantasizing, waking gastic activity, heart rate at rest, eye movements, and sexual excitation.
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