Action for Happiness - Sleep with Russell Foster Tues 5th June Flashcards
The Circadian System adjusts or “Fine-Tunes” Physiology and Behaviour to the profound yet predictable demands of the 24h Day/Night Cycle
Blood pressure is highest at 8:30am. This is when people are at the highest risk of a blood clot, and therefore susceptible to stroke.
A couple celebrating their 60 year wedding anniversary have been asleep for 21.5 years of that time.
Thomas Edison: “Sleep is a criminal waste of time and a heritage from our cave days”
Sleep promotes the ability to come-up with novel solutions to complex problems!
Salience = the quality of being particularly noticeable or important; prominence.
Sleep and negative salience: patients who have been sleep deprived for 36 hours remember more negative associations/words.
Sleep is a global brain event.
There are at least eleven (almost definitely more) neurotransmitters and hormones that play intimate roles in the sleep-wake cycle:
Orexin (hypocretin): Orexin is a neurotransmitter that is linked to arousal and wakefulness and is almost exclusively produced in the hypothalamus.
Norepinephrine can act as both a neurotransmitter and a hormone. It is probably best known as a stress hormone and one of the main components in the flight-or-fight response
Dopamine is a neurotransmitter that is best known for it’s role in the regulation of motor function as well as it’s depletion during Parkinson’s Disease which leads to motor dysfunction.
Dopamine seems to regulate sleep-wake states and helps control when we enter each.
Melatonin is the hormone that is most commonly associated with the sleep-wake cycle. The levels of melatonin are regulated by the suprachiasmatic nucleus of the hypothalamus which reacts to the amount of light in the environment. So the darker it is outside of the body, the more melatonin there is.
Serotonin is a neurotransmitter that is commonly associated with depression.
Cortisol is a steroid hormone and is often released in response to stress.
Adenosine is an inhibitory neurotransmitter that is involved in promoting sleep. After you wake up, adenosine levels begin to build up in your brain throughout the day causing you to become more and more sleepy. The most common of the adenosine antagonists is caffeine.
Homeostatic drive = sleep/wake pressure
Homeostasis refers to the ability of the body or a cell to seek and maintain a condition of equilibrium or stability within its internal environment when dealing with external changes.
The homeostatic drive and the circadian drive are independent of each other and responsible for when/how we sleep.
Shift work and Jet Lag profoundly disrupts the homeostatic vs circadian drive.
Suprachiasmatic nuclei (SCN) = the master body clock.
Clinical ophthalmology must appreciate that the eye provides us with BOTH our sense of space and our sense of time.
We may inadvertently make the problems of sleep disruption worse by providing a weak light/dark signal to the clock.
Sleep & Circadian Rhythm Disruption (SCRD)
Short-Term
- Loss of Attention
- High level of Micro-Sleeps
- Failure to Process Information
- Impulsivity, Loss of Empathy, Negative Focus
- Memory Impairment, Increased Mistakes
- Reduced Cognition and Creativity
Long-Term
- Immune Suppression
- Increased Infection/Cancer Risk
- Increased Cardiovascular Disease
- Risk of Diabetes II
- Metabolic Syndrome
- Increased Stimulant/Sedative Use
“Mental Illness Vulnerability”
- Mood Instability
- Anxiety, Paranoia, Hallucinations
- Exacerbation of symptoms in BPD & SCZ
Sleep disruption = too little leptin and too much ghrelin
Leptin is the chemical that tells your brain when you’re full, when it should start burning up calories and, by extension, when it should create energy for your body to use.
The purpose of ghrelin is basically the exact opposite of leptin: It tells your brain when you need to eat, when it should stop burning calories and when it should store energy as fat.
When you don’t get enough sleep, you end up with too little leptin in your body, which, through a series of steps, makes your brain think you don’t have enough energy for your needs. So your brain tells you you’re hungry, even though you don’t actually need food at that time
People who don’t sleep enough end up with too much ghrelin in their system, so the body thinks it’s hungry and it needs more calories, and it stops burning those calories because it thinks there’s a shortage.
Sleep efficiency is the ratio of the total time spent asleep (total sleep time) in a night compared to the total amount of time spent in bed.
Sleep is the most effective cognitive enhancer we have.
A phenotype in genetics is a set of observable characteristics that result from the interaction of one’s genotype (instructions carried with genetic codes) with the environment.
It basically refers to how genetic information is expressed in reality. Phenotypes are the observable things like eye color, hair color, height, shoe size, some behaviors and other traits.
In terms of sleep, studies have confirmed a significant heritability of usual bedtimes, sleepiness and sleep duration with links to genes that regulate various components of the circadian clock.
Sleep phenotype (also known as chronotype) refers to an observable pattern of behaviors with genetic links, in this case, tendencies toward earlier bedtimes and wake times or later bedtimes and wake times.
You don’t need genetic testing to figure out your sleep phenotype – simply consider your sleep habits and normal schedule.
Chronotype (night owl vs morning lark) - take the Munich Sleep Questionnaire
An owl on the morning shift will suffer much more than a lark.
Half of junior doctors having accidents or near misses after night shifts.
Driver drowsiness detection is a car safety technology which helps prevent accidents caused by the driver getting drowsy
For shift work couples with children under 19-years old, the risk of divorce increased up to six times when one of the spouses worked between midnight and 8 a.m. as compared to daytime hours.
Avoid electronic devices within 2 hours of sleep as the light will keep you awake.
Ideal bedroom temperature is 18 to 19 degrees.
Try not to eat within 2 hours of going to bed.
The majority of psychiatric inpatients experience clinically significant insomnia.
Sleep disruption and mental illness have overlapping brain circuits and neurotransmitters.
Reduction of sleep disruption should improve the level of mental illness
Insufficient Sleep Is Suggested By:
- The need of an alarm or person to wake you
- Takes a long time to wake-up - sluggish
- Oversleeping on free days (weekend or holiday)
- The need of stimulants (e.g. caffeinated drinks) to wake and sustain wakefulness during the day
- The need or desire to take a nap
- Loss of empathy and increased irritability
- Increased impulsivity and risk taking
- Mood swings – noted by you or others
- Failure to concentrate or process information
Developing a good sleeping environment
Removing distractions from the sleeping space such as television, computers. Make the sleeping space a place for sleep.
Keep the sleeping space dark, not too warm and quiet.
Invest in a comfortable bed, mattress and pillows.
Try to maintain a consistent bedtime and wake-up time.
If you wake minimise light exposure, don’t lay in bed frustrated but relax elsewhere and then return to bed.
Adopt a regular routine that you find particularly relaxing, such as reading or listening to music.
If you cannot cope with your bed partners snoring, find an alternative sleep space. This does not reflect upon your relationship.
Limiting stimulation before bed
Minimize light exposure 30 min before desired sleep time and keep lights low in the sleeping space prior to sleep.
Eat at the same time and finish the final meal of the day no later than three hours before desired bedtime.
Avoid caffeinated drinks in the afternoon and certainly before sleep.
Avoid the use of alcohol or other sedatives to induce sleep.
Engage in regular physical exercise, but not within 4 hours of going to sleep.
Avoiding stressful situations before sleep
Avoiding napping. If you nap then not for longer than 20 min and never 4 hours before sleep.
