Lecture 9 - Meditation and sleep

sleepers in the population

mean for adults is 7-8hrs, there is some cultural and individual variability, there is no magic number of hours it all depends on exercise, stress and genetics

why do we need sleep?

maintenance of the brain (clearance of waste) and restoration of injured/damaged tissue, ontogenetic development of the brain, key to learning + memory processes, energetically favorable, sleep facilitates learning and memory processes, periods at night you are vulnerable and unable to complete certain tasks

sleep stages

brai activity during sleep has been extensively studied using EEG, readout of electrical activity in the brain, has really good temporal resolution (moment to moment readout)’ consciousness and arousal have minute differences that happen very quick, there are four distinct activity patterns corresponding to sleep stages, one REM stage and 3 NREM stages

breaking down sleep with EEG

all of these scales are voltage variations that are electrical overtime, studied electrical acitvity in the brain, found multiple characteristics that are markers of different sleep stages, sleep architecture is the normal architecture we tend to see, REM has fast activity but this is not true for older adults, useful to study patterns someone has to see if it deviates from normal patterns of activity

NREM1

light sleep, slightly lower frequency activity, includes alpha and theta waves

NREM2

lower frequency activity (theta) with sleep spindles and k-complexes

NREM 3/4

deep sleep or slow wave sleep, mostly very low frequency activity (delta) and some spindles, efficient sleepers sleep more than 6 hours, spending more time in NREM3, short sleep is likely to have few components and less of the restful components

REM stage

dream stage, high frequency activity, similar to eyes-open wakefulness, atonia (no movement

sleep and aging

change in sleep cycle as you age is normal, getting up earlier and earlier

sleep in the elderly

greater sleep latency, takes longer for you to fall asleep, more arousal periods (waking up more frequently), less REM so less dreaming, less NREM3 so less deep sleep and less overall sleep

sleep problems

10% of ppl may experience sleep disturbances, more common in the elderly (50%), often with other problems, these issues are associated with reduced productivity, increased medical costs and increased motor vehicle accidents, in the US alone, sleep issues are estimated to cost 60 billion directly and a further 30 billiion due to medical expenses

sleep and the student

students are much more likely to report poor sleep (50-60%), 10% meet criteria for a sleep issue, poor sleep linked to less study time and lower GPA, sleep quality moderated by intrapersonal adjustment, friendship quality and academic stress (40%)

types of sleep problems

insomnia is the most well studied, but there is also narcolepsy, sleep apnea, and restless leg syndrome

insomnia

difficulty falling asleep or staying asleep, it can be acute or chronic (more than 3-6 months) and recurrent, primary insomnia is rare making up only 10% of cases whereas secondary/comorbid insomnia (90%) is common, it has frequent comorbidity with depression and anxiety, it is important because these disorders are treated by meditation

what causes a sleep problem?

there are many causes like other medical issue, from a physiological perspective hyperarousal is connected with stress, activation of the sympathetic nervous system and hypothalamic-pituitary adrenal (HPA) axis, one of the main products of HPA is cortisol which is involved in sleep regulation, shows some response to meditation, it can also be causes by pre sleep worries and negative cognitions regarding sleep which factor into insomnia, mindfulness may reduce these behaviors by discouraging rumination and encouraging acceptance, reductions in stress may be linked to changes in cognition, especially in the case of MBCT

measuring sleep in the lab

the two major approaches include objective and subjective analysis

subjective analysis

first one involves surveying the patients about their sleep patterns using questionnaires, relies on patient self report, questionnaires include athens insomnia scale, pittsburgh sleep quality index and insomnia severity index, also sleep diaries to record the patient’s sleep behaviors

objective analysis

requires observing neurological and physiological activity during sleep

sleep diaries

record patient’s sleep behaviors, log when you exercise, sleep, drink, etc for 2 weeks, C stands for coffee or caffeinated products, A stands for alcohol intake, there is a weird association with sleep and many ppl who use it feel drowsy but chronic use impairs sleep

benefits of subjective analysis

cheap, quick and accessible, only need questionnaires and trained professionals, no equipment needed, first and necessary step in addressing a sleep problem in the clinic, all studies include subjective analysis, informative of the patient’s attitudes and beliefs, and may help identify other problems they might have

more approaches are required

subjective analysis is useful but it doesn’t address physiology, relies on honest and accurate patient reports, need for additional approaches, objective analysis can be achieved with polysomnography study which includes many tools (EEG, EMG, EOG, ECG, breathing monitors, etc)

what are the major variables of objective analysis?

sleep latency (how long it takes to fall asleep), time spent awake and number of awakenings, total time asleep and time spend in various states including NREM1-3 and REM

what are the drawbacks of objective analysis?

even though its very informative, it is time consuming and costly so you need space, equipment and expertise, it is not preferred for laboratories with limited resources, perhaps for this reason, many studies in the meditation do not include objective analysis (probs one of the biggest issues in this area)

treating sleep disorders

sleep education, cognitive behavioral interventions, pharmacotherapy and meditation

sleep hygiene

go to sleep at the same time every night, avoid electronic screen 30 mins before bed, etc, this is correlated with fewer sleep problems in uni

pharmacotherapy (PCT)

number of students take meds (prescription or over the counter) to treat sleep issues, among prescription drugs, benzodiazepines are often used for short term period (ex; xanax, ativan, valium and clonazepam), drugs are not preferred for long term use because there is a high risk of toxicity, tolerance, addiction, withdrawal, memory impairment and driving impairment

alternatives to drug treatment

non-benzodiazepine drugs are increasingly used like lunesta, ambien and sonata, they are viewed as less toxic than benzos but not more efficacious, other substances like melatonin may be useful (regulates sleep-wake cycles)

melatonin and sleep patterns

melatonin levels begin to rise several hours before sleep starts

drugs vs MBSR pilot trial

MBSR reduced sleep onset latency and awakenings after sleep onset while increasing sleep efficiency, effects were similar to but weaker than the effects of PCT

cognitive-behavioral treatment interventions (CBTIs)

this involves getting someone to change their cognitive relationship with sleep and adopt new sleep related cognitions, similar to CBT for anxiety, depression and pain, may be more ideal for long term management

drugs vs CBT

most drug effects decline overtime but this does not seem to be the case for meditation as effects persist, CBT is associated with more prolonged changes in sleep latency and efficiency than PCT

CBT vs PCT

if practice is continued, the effects of CBT may last up to ten years or more after the termination of treatment, CBT is also associated with better reaction to relapses than hypnotic drugs like benzodiazepines

MBTI

total wake time is reduced as is pre sleep arousal and ISI score, its better than standard MBSR alone and simple self monitoring because it is pain focused, includes cognitive and behavioral components MBSR lacks and reduces catastrophizing more strongly, it provides more guidance and structure than self monitoring, produces greater changes in pain unpleasantness, combines mindfulness with skills that generalize

mindfulness meditation effects on sleep

greatest effect is on perceived sleep quality, has smaller effects on total wake time, greater effect than no specific active controls like relaxation but does not differ much from evidence based treatments like drugs

meditation sleep and aging

interestingly, one study suggests that meditation may preserve young sleep architecture into middle age, while cross sectional studies suggest that older vipassana meditators have sleep patterns more similar to younger adults, improvements in sleep are thought to underlie many of meditation’s other effects like mood, memory and pain

controversies

the field is not in universal agreement, notable criticism in the area that there is a lack of experimental research, there are reports of meditators sleeping less, britton et al study complicates this saying long term meditation is associated with less sleep

britton et al study

polysomnography study in a patient population before and after mindfulness meditation training, consistent with prior studies, they found that meditation increased self reported sleep quality and improved mood, surprisingly observed that meditation was associated with higher arousal, less time spent in deep sleep and more time in light sleep, such changes are normally associated with reduced sleep quality so paradoxical, meditation decreases slow wave sleep and increases arousal awakenings and stage 1 sleep

what do these changes in the britton et al study mean?

appears that meditators are sleeping less but somehow feeling better, long term meditation is associated with decreased sleep need, long term meditators may require less rest to achieve normal function, the study might explain anecdotal reports of disrupted sleep in meditation retreats, meditation may have these effects because it disrupts key neural networks, especially the default mode network, another explanation may be the patient populatio, the sample of individuals in remission from depression, other population sof insomnia patients and healthy contorls may respond differently

default mode network

group of brain structures that is involved in self referential processing and mind wandering as well as sympathetic arousal and sleep, dysregulated in depression and insomnia