Dolly Chauhan M,pharm

1. Made by; Dolly Chauhan
M.pharm(pharmacology)
2st semester

2. The term circardian comes from Latin
words namely “circa” means around
“diem/dies” means day
Circardian means “approximately one day”

3.  Ethology is of study of animal behaviour in a
normal environment.
 The term ‘behaviour’ denotes “what an
organism does”
 All behaviour patterns are co-ordinated
sequences of neuromuscular activity.

4.  Chronobiology is a field of biology that
examines periodic phenomena in the
biological processes of living organisms.
 “chrono” means related with time ; ‘biology’
means science of life.
 Thus chronobiology is the study of science of
life in relation with time.
 ‘Biological rhythmicity’ is an integral part of
the organiztion of living matter.

5.  Biological rhythms are an integral part of
every day life for most orgainsms on earth.
 They regulate most important functions in
each organism.
 In plant circardian clocks control flowering,
response to seasons and photosynthesis.
 In mammals, circardian clocks manage
sleeping , waking , feeding and controlling
whether an animal is noctural or diurnal.

6.  A 24 hour biological rhythm controlled by
“pacemaker” in the brain that sends
messages to other systems in the body.
Circardian rhythm influences various
regulatory functions, including the sleep-
wake cycle , body temperature regulation,
patterns of activity such as eating and
drinking and hormonal and neurotransmitter
secretion.

7.  A Circardian rhythm is any biological process
that displays an endogenous, entrainable
oscillation of about 24 hours. Although
circardian rhythm are endogenous (“built-in ,
self sustained ), they are adjusted
(entrained) to the local environment by
external cues called zeitgebers, commonly
the most important of which is daylight.

8.  The master clock controls circardian
rhythms.
 It consists of a group of brain cells in the
hypothalamus called supra chiasmatic
nucleus (SCN).
 The hypothalamus continually measures the
light exposures via the retinal hypothalamic
tract and accordingly adjusts the timing of
the sleep-wake cycle.

9.  Seasonal affective disorder-SAD is an
infradian rhythm disorder. SAD may have
disturbance in the melatonin system.sad
people show low mood effects in winter
months.
 Jet lag- influences our endogenous pace
maker.
 Symptoms include triedness, sleepiness ,loss
of concentration , anxiety , depression and
irritabilty.

10.  Growth hormone- increase during sleep;
decrease during wakeful state.
 Cortisol- highest during morning; lowest
during sleep.
 Prolactin-resembles like growth hormone
cycle
 Aldosterone-peaks in afternoon; declines in
evening
 Testosterone-low in afternoon ;high in night.

11.  What is the master clock?
 A master clock in the brain coordinates all
the biological clocks in a living thing, keeping
the clocks in sync. In vertebrate animals,
including humans, the master clock is a
group of about 20,000 nerve cells (neurons)
that form a structure called the
suprachiasmatic nucleus, or SCN. The SCN is
located in a part of the brain called the
hypothalamus and receives direct input from
the eyes.

12.  What are circadian rhythms?
 Circadian rhythms are physical, mental, and
behavioural changes that follow a daily
cycle. They respond primarily to light and
darkness in an organism's environment.
Sleeping at night and being awake during the
day is an example of a light-related circadian
rhythm. Circadian rhythms are found in most
living things, including animals, plants, and
many tiny microbes. The study of circadian
rhythms is called chronobiology.

13.  What are biological clocks?
 Biological clocks are an organism’s innate
timing device. They’re composed of specific
molecules (proteins) that interact in cells
throughout the body. Biological clocks are
found in nearly every tissue and organ.
Researchers have identified similar genes in
people, fruit flies, mice, fungi, and several
other organisms that are responsible for
making the clock’s components.

14. A Zeitgeber is any external or environmental
cue that entrains, or synchronizes, an
organism’s biological rhythms to the earth’s
24 hour light/dark cycle and 12 month cycle.
Eg;
Light
Temperature social interactions
Pharmacological manipulation
Exercise
Eating/drinking patterns

15.  The classic phase markers for measuring the
timing of a mammal’s circadian rhythm are;
 Melatonin secretion by the pineal gland
 Core body temperature
 Plasma level of cortisol

17.  New baby- 16 to 20 h
 Child – 10 to 12 h
 Age 10 -9 to 10 h
 Adolescence -7 to 7.5 h
 A gradual decline to about 6.5 h develops in
late adult life .
 35 years of age onward, women tend to sleep
slightly more than men

18.  Circardian rhythm disorders occur when
individuals attempt to sleep at times that are
inconsistent with their underlying biologic.

19.  Intrinsic Circardian rhythm Disorders
 Delayed Sleep Phase Syndrome (DSPS)
 Advanced Sleep Phase Syndrome(ASPS)
 Irregular Sleep wake pattern
 Non 24 hour sleep wake syndrome
 Extrinsic Circardian Rhythm disorders
 Shift Work
 Time Zone Change Disorders

20.  Intrinsic circardian rhythm disorders refer to
desynchronizes between attempts to sleep
and the sleep wake circardian rhythm that
are due presumably to internal rather than
external causes. These disorders might result
from weak circardian rhythm or from an
inability to entrain the rhythm to the
environment.

21.  First identified by Weitzman et.al (1981) as
“chrono biological disorder with sleep onset
insomnia.”
 Sleep wake circardian rhythm is delayed
compared to the time the individual
attempts to sleep
 Individuals report difficuility falling asleep
at desired bedtime but have normal sleep if
they attempt to sleep a few hours later.

22.  Individual with DSPS show late sleep onset ,
few awakenings, early wake up times when
work or social demands are present ,and late
(mid afternoon) wake up times when there
are no such demands on their time.
 Delayed sleep phase individuals commonly
identify themselves as “night people” and
report being alert during late evening and
night hours.

23.  Inability to stay awake until the desired
bedtime and inability to remain asleep until
the desired wake up time.
 Typical sleep onset times are between 6 P.M.
and 8P.M. and no later than 9P.M. and wake
times are between 1A.M. and 3A.M. and no
later than 5A.M.

24.  The current approach to treating ASPS is
bright light exposure in the evening and
avoidance of light exposure (e.g. wearing
dark, wrap around sunglasses) in the
morning. Bright light exposure in the evening
and the avoidance of bright light in the
morning , it is thought , help to re entrain
the sleep wake cycle into circardian rhythm.

25.  This rare disorder is characterized by a
variable and disorganized sleep wake pattern
that suggests the absence of circardian
rhythmicity.
 Sleep is broken into several short sleep
episodes, but the cumulative sleep for 24
hour period is at normal levels.

26.  Polysomnographic studies show no
abnormalities in sleep parameters except for
the short duration of each episode.
 Common in elderly people with dementia.
 Treatment consists of gradual decrease in the
number and duration of daily naps. Increase
in activity levels and social interaction is
recommended to facilitate the process.

27.  This is a disorder in which individuals are
unable to entrain to 24 hour day and instead
maintain 25 to27 hour sleep wake cycles.
Some individuals with this syndrome tend to
progressively phase delay. The disorder is
rare in general population and is assumed to
have higher prevalance among blind people.

28.  Other names
 Non 24
 Free running disorder (FRD)
 Hypernychthermeral disorder
 Circardian rhythm sleep disorder –free
running type and nonentrained type
 Non 24 hour circardian rhythm disorder
 Non 24 hour sleep wake disorder

29.  It is a chronic circardian rhythm sleep
disorder.
 It can be defined as “chronic steady pattern
comprising one to two hour daily delays in
sleep onset and wake times in an individual
living in society”.
 The pattern of delay persists literally
“around the clock ”,typically taking a few
weeks to complete one cycle.
 This disruption of body clock causes cyclical
bouts of night time sleeplessness and
excessive daytime fatique and napping.

30.  Treatment focuses on entraining the
circardian rhythm to 24 hour day through
social interaction ,exposure to light and
melatonin.
 Melatonin has been successful in treating this
disorder in blind individuals.

31.  Shift Work
 Time Zone Change disorders

32.  A disrupted sleep wake schedule often
results in
 Disturbed and shortened sleep
 Sleepiness on job
 Reduced performance levels
 Psychological distress due to disruptions in
family and social life.

33.  Dyssomnia associated with rapid time zone
change (“jet lag”) is due to desynchrony
between the endogenous sleep wake rhythm
and the light/dark cycle.
 Symptoms include an inability to sustain
sleep and excessive sleepiness.
 For most people ,these symptoms subside
after a few days, depending on number of
time zones crossed.

34. Frequent travellers, such as transatlantic airline
crews, may experience more persistent difficulties.
Westward travel is associated with disturbed sleep at
the end of the sleep period, which coincides with
habitual wakeup time, and eastward travel is
associated with sleep onset insomnia

35.  Bright light treatment
 Melatonin administration about an hour
before bedtime in the new time zone

36.  DSP is more common in teens and young
adults, occurring at a rate of 16 percent
 ASP is more common as people
 age, occurring in about one percent of
middle aged and older adults.
 Irregular sleep-wake rhythm may occur in
nursing home residents and other people
who have little exposure to time cues such as
light, activity and social schedules

37.  Free-running (nonentrained) type occurs in
more than half of all people who are totally
blind.
 Jet lag can affect anyone who travels by air,
but symptoms may be more severe and may
last longer in older people and when anyone
travels in an eastward direction.
 Shift work disorder is most common in
people who work night shifts and early
morning shifts

38. Sleep loss
Excessive sleepiness
Insomnia
Depression
Impaired work performance
Disrupted social schedules
Stressed relationships

39. Behaviour therapy or advice about sleep
hygiene.
Avoid naps, caffeine, and other stimulants.
Bright light therapy
Blue blocking glasses therapy
Medications such as melatonin and modafinil
(Provigil) promote wakefulness.
Tasimelteon is a melatonin receptor agonist
that is used for treatment of non 24 hour
sleep wake disorder in blind individuals.
Sleep phase chronotherapy

40.  People who suffer from delayed sleep phase
syndrome are generally unable to reset their
circadian rhythm by moving their bedtime and
rising time earlier.
 In sleep phase chronotherapy, an
attempt is made to move bedtime and
rising time later and later each day, around
the clock, until the person is sleeping on a
normal schedule.

41.  Obtain a thorough and careful sleep history
both from patient.
 Ask patient to maintain a sleep diary which
include all sleep histories.
 Maintain a regular and consistent bed time
and wake time that is similar to both
workdays and non-work days

42.  Develop a regular relaxing bed time
routine about 1 to 2 hour before sleep
onset.
 Establish comfortable sleeping conditions
most conducive to good sleep.(cooler room
temperature, darkness, and low noise levels)
 Avoid going to bed hungry.

43.  Exercise regularly, but avoid vigorous
exercise within 2 to 3 hours of sleep
onset.
 Spend some time outside each day.
 Avoid exposure to bright light in the evening
before bed and encourage exposure to bright
light in the morning

44.  Avoid stimulants such as stimulants in the
evening.
 Do not use alcohol to facilitate sleep
initiation; this is likely to result in sleep
fragmentation later in the night as blood
alcohol levels fall.
 Refer patient to a sleep specialists for
diagnostic procedures like
polysomnography actigraphy etc.