kins4400 notes

concussion - shaking the brain
- coup and contracoup when brain shakes in skull from bakc/front, side/side
- each one is different (heterogeneous)
- everyone responds differently depending on where their brain is injured

what happens in the brain
- disruption to the axons (cell membrane gets stretched or twisted a little bit, bc of this the channels that bring ions in and out don't work right); can't see injury easily even with MRI
- disruption of glia and neuronal axon
- neurotransmitter - glutamate
- induce concussions in rats (different controlled injuries and see what gets hurt/what doesn't, observe ionic changes)
- brain gluclose and blood flow goes down when the brain needs more o fthose things; "energy crisis"

- inflammation to the brain have unusual effects; longer lasting?
- changes in blood brain barrier - can be damaged in concussion, things flow out o fbrain that shouldn't and into that shouldn't
- look at components of blood brain barrier and see if what shouldn't be in the blood is

- fruit fly studies
	- group in wisconsin
	- genetics are totally described
	- if you give them a concussion you can see what genes are altered
	- put in test tube, slam test tube w/ a spring; some act stunned (behavioral changes)
	- look at why do some survive and some die
	- the ones that survive have different genes for blood brain barrier
	- the genes for gut proteins (that make structure of gut), those are different that survive as well
	- "maybe if we change the feeding schedule, more may live?" and it's true; flies that are straved survive better than those that overeat

common signs and symptoms after head injury
- difference between a symptom and a sign
	- symptom - self report
	- sign - things you can objectively measure
- mainly what we have with head injuries are symptoms
- most common symptoms - dizziness and headaches

epidemiology
- most common head injuries from car wrecks, war-related
- sport ones are mild traumatic head injuries
- greatest risk for concussions is with youth (19 to less)
- even though they have statistics, a lot of people may have a concussion but they don't want to go to the doctor and many just tuff it out
- a lot more kids on bikes than those playing football, but doesn't account for exposure time
- bike, football, playground - the three most common source of kid head injuries

- large study - high school national sample
- represent the US
- what sports get highest number of concussions, acocunting for 10,000 competition exposures (games)
- concussion rate is highest in football
- ankle injury is 5x as likely as a head injury in most sports
- girls have a higher rate of soccer concussions


[LOG]
Why would girls have a higher rate of concussions than boys?
- Girls are ruthless.  They are absolutely horrifying and out for blood.  Boys are expected to be aggressive, but girls are expected to be polite and the like, so in sports when they're allowed to be aggressive, they ARE.
- Girls may have smaller shoulders so they may be less likely to brush shoulders and more likely to slam heads than guys (who would catch shoulders).
- Guys may be less likely to self-report concussions than girls.
- Women may not have as well-trained neck muscles, may cause their head to snap around more aggressively.
- Potential differences due to maturity and how women's brains develop at a more rapid rate (since these are high schoolers).
- Potential difference in center of gravity?
- Estrogen may have an impact in how well the brain copes with an injury.

college sport induced concussions
- 1000 games, if you have 100 athletes on a team and you play ten games
- women's hocky has the most concussions; more in spring football over fall football (competing for positions, a little untrained, the type of training pattern, etc.)
- WAY more injuries in competition and in college
	- 5x more likely to get injury in competition than in practice
	- college students are faster and quicker; if you hit something, head's more likely to snap around

what are risk factors for concussion
- if someone's had a history, they're more likely to get one (most important!) (most consistent, best predictor)
	- teach them to do something differently?
- competition - higher risk in game than in practice
- exposure time - the more games you're in, the greater the risk
- age - college has higher prevalence, but younger people get more than older people
- female gender - data strongest for soccer, basketball
- type of sport - football, hockey, biking highest risk
- type of position - quarterbacks and wide receiver
- technique - "spearing" technique worse
	- practices where they played w/out helmet, they had to learn how to use the correct techniques

worse case scenario
- you die from this (WELL THAT'S GRIM)
- permanent serious brain injuries
- multiple injuries put them at greater risk for death scenario (second impact syndrome)
- neurological recovery - worse in high school players
	- why are kids at greater risk? worse technique; weaker necks; cells are immature and damage more easily; cells die more easily BUT neuroplasticity

when people go to altitude, they get higher intracranial pressure
- odds of getting concussion lower when played at altitude (look at that slide w/ the rams)
- brain doesn't slosh around as much
psychophysiological consequences
short term and long term effects

research in boxing
- natural experiment (people choose to get hit. because boxing)
- 38 boxers and 28 controls; matched on age, weight, education (looking at cognition), learning disorders, etc
- conditions - boxing a match or boxing a bag
- 5 were knocked out with an average of 8 punches to the head
- look at neuropsychological test battery pre and post (5 minutes after)
	- hope are tapping into different cognitive functions

- recall (asking to remember features about a story or pictures); data showed a change in cognition; biggest difference were for short term and long term logical memory

on-field assessments post-concussion
- graded symptom checklist
	- used to denote intensity of symptoms
- standardized assessment of concussions
	- important to get baseline scores

time course of symptom and cog recovery
- CC - during the game; pg - post game
- huge increase in symptoms for injured players; gradually gets better and they recover within seven days (USUALLY)
- in theory, much better to do cognitive test (where you can't just lie abt not having symptoms); lower scores--doing worse

look at the summary page
- increase in symptoms by more than 3 SD; resolves within 7 days generally
- cognition is less affected, but memory takes a hit (difference is 1 SD); other cog tests, there's a smaller effect (ie attention); resolve within 3 days on average
-  neg effects can be greater and recovery can be slower for younger poeple and people with prior concussions (as examples)

neurophysiology
- you can't fake it (electrodes don't lie motherfucker)
- one type is measured during sleep (polysomnography)
one study of sleep, small sample (11 concussed/11 nonconcussed)
- measured sleep time and wake time for both groups
- didn't show that sleep was screwed up w/ concussed people
- sleep quality bad for concussed people; data is different for self reports vs. actual physiology

another study
- are you more likely to get concussed if you're a bad sleeper and will it be more intense?
- high schooler study
- 34 had difficulty sleeping at baseline
- looked at verbal memory and reaction time
- those w/ sleep symptoms at outset were worse on verbal memory and slower reaction time when they had a concussion

event-related potential technique
- present something many times, get an average of how your brain responds (highest response is at the "novel" first presentation), take the average

symptomatic - symptoms present
asymptomatic - had symptoms but they got over it
the left graph focuses on the novelty and how the brain reacts to it

focus on the parietal (bottom left)
- around 300 milliseconds, the brain reacts to new novel stimulus

people with brain diseases have a p300 is low

you'd predict the symptomatic group would be worse off ,but the aysymptomatic group aren't in the clear either

------

mood disorders
KEVIN GUSKIEWICZ - genius award (the only one in our department/field ever to get one)
	- done w/ reserach re: concussion in sports
- study with retired pro football players
	- 6.6 year career
	- looked at number of people who had clinical depression w/ re: to how many concussions they'd had
	- on average, 54 yo guys (15% have had clinical depression) in the normal population
	- lower when they have zero concussions and higher w/ 3 or more
	- people physically active have higher mental health in general
	- appears to be dose response w/ re: to number of concussions and if they had clinical depression

mood effects associated w/ alterations in brain white matter and regional brain blood flow measured w/ fMRI
- also using diffusion tensor technique, looks at axon integrity; get a sense for how axons are doing (healthy or not?) based on presence of white matter

fMRI
- 40 male athletes, consisten post concussed symptoms
- comared to male nonconcussed athletes
- put in MRI, measured blood flow in brain while doing working memory task
- no difference on working memory task performance for either party
- brain blood flow was different; injured athletes
	- dorsilateral prefrontal cortex - showed correlation with BDI scores and blood flow; linking this to depression symptoms; significant correlation
	- more symptoms of depression -> lower blood flow
	- anterior cingulate cortex activity did not have the expected decrease in activity in the ones w/ symptoms of depression

white matter integrity study
- different technique, "state of the art"
- difussion tensor imaging
	looks at if there's pathology in the axons
	- a lot more red/damage in the retired NFA players
- can be done on someoen who is alive (important!!!)

onset of dementia-related syndromes may be linked to concussions
- get info from physician diagnosis; self report; ask spouse
- sees same pattern of response across all three data sets (more likely to have diagonossi of mild cog impairment if you've had more concussions)

1928 - punch drunk syndrome
- had problematic movement and speech; could be related to the punches the took (induced by getting hit in the head)
- dementia pugilistica was the enxt name
- then chronic traumatic encephalopathy
- CTE - hypothesized (still a lot of disaggrement), supposed to be progressive but no one's followed it over time, all based on autopsy reports; only within the lst few months that pathologists tried to define what CTE is (accumulation of phosphorolated tau protein)
- tau - protein found in the brain, stabilizes cytoskeleton of the enrve cell; builds up too much and forms tangles and amyloid plaques (dense matter atteched to cells so they don't function right)
- this protein is a halmark of alzheimer's
[log]
think of a time in physical activity or exercise that when you first did it, it felt different when you did it later
- swimming breaststroke, one meet it felt very different and i was able to go more quickly?
- adrenaline, perhaps getting in the right cadence?
- mind on something different?
- just somehow finding the "sweet spot" rhythm wise?

- mental aspects
	- pacing - important aspect re: how you feel
	- expectations -
	- motivation
- training status
- drugs

why does one day it 'feel' hard or easy and how to we use that to optimize training/performance

definition of perceived exertion
- how strenuous the exercise (exertion) feels or the perceived intensity of the effort given
- independent of how the thing moves, how the muscle feels; how much did you FEEL you put into it
- also referred to as RPE

psycholbiological gestalt
- exercise stimulus - duration is longer, feels more effortful
- physiological factors - affect how you perceive exercise; are you eating/fasting? lactate threshold moved?
- psychological - the one we know the least about
- milieu - the other shit (the environment, etc.)

assessign perceived exertion
scale type - possible operation
- nominal - classification
	- doesn't mean anything; it's like the number on the back of a jersy; don't tell you anything meaningful other than giving "you" a name
- ordinal - rank order
	- order; first second third; most psych scores are this way
- interval - distances
	- this and ratio can give you an idea of magnitude of difference; meaninful differences between intervals (differences in temp?)
- ratio - ratios
	- most sophisticated; the one you strive for; has a true and meaningful zero point (the absence of whatever it is you're measuring); looking for the abscence of any weight; 2 key things - true zero point and can go to infinity
	- ex. kelvin - the absence of thermal energy (celcius/farenheight are both arbitrary zeros)
	- you can measure perceived exertion with ratio scales
	- usually looks like it's measured at interval scales but really it's ordinal
	- can have different number systems so it can be hard to compare scales

advantages of ratio scales
-

ratio scales
- magnitude estimation
- magnitude production
- cross-modality matching

loudness of voice
- 9
- 23
- 2

magnitude estimate - how heavy was that weight? how fast are you going? how do you FEEL about this? estimate the magnitude yourself, how do you perceive intensity?

magnitude production
- pick a speed that feels half/twice as fast of how fast you're moving right now; ratio scaling

cross-modality matching
- using a different sensory mode to determine a ratio

ratio scale results
- force v. magnitude estimation - it's not linear!
- newtons v. arbitrary units - the line isn't!!! linear!!!
- an actual, physical objective measure of the exercise stimulus
- you'd think it'd be linear but it's not!
- greater change of perception at higher work loads; but you only see that if you measure with a ratio scale
- gives you a different picture from the borg scale

definition in words of the relationship between exercise stimuli and perception of effort [when measured using a ratio scale]!!!!! important know this

look @ steven's power law
- applies across sensory modalities
- magnitude (mean perception of effort across subjects)
magnitude = k times (stimulus intensity (watts) raised to the power of 1.6)
- if it were 1.0, it would be linear; since it/s 1.6, that means it opens up like a cup
- if given a constant and watts, do the math to get magnitude
	- psychophysics

ratio scale
- advantage - more accurately describes relationship between perception
- disadvantages of ratio scales
	- interindividual comparisons aren't possible

GUNNAR BORG
- important figure in exercise science
- developed a method nearly everyone uses (RPE scale)

- why six to 20?
- correlates to hr!
- multiply it by 10, you can estimate hr in cycling exercise
- linearly shown (meaning it's incorrect into how it actually feels, not a ratio scale)
	- category scale

borg 6-20 scale
- most commonly used, good for all applications
- works really well, despite not being FULLY accurate (but reliable and valid)

0-10 scale
- category scale but with ratio properties
- meant for studying non-linear exercise response

lactate - curved lienar response to exercise
- 0-10 scale good in this case!

heart rate - linear response to exercise
- 6-20 scale good in this case

key disadvantage of 6-20 scale
- ceiling effect - people will inaccurately respond so they don't feel like they don't wanna hit the ceiling of the scale
- not a ratio scale
- assumes that all maxes are perceived the same (range principle)
	- someone deconditioned v. someone elite - their maxes FEEL the same despite their status
	- suggests a relationship between relative exercise intensity and perception

instructions
- define perceived exertion
- explain differentiated ratings
	- overall
	- local - working muscle
	- central - how effortful does it feel as you're breathing
- no right or wrong answer (just answer honestly)
- anchor the perceptual range
	- present stimuli - have people walk at a certain pace, give them a rating on the scale; anchors highest intense stimulust at v hard and least intense at v light
	- by definition - tell people what you mean by a certain speed intensity (very light - super easy walk; very hard - oh god your house is on fire and your kid's inside, you gotta run to save them)

0-10 scale
- maximal - if you feel an effort greater than ten, you can give a number but make sure you think abt it in terms of ten (allows you to go above the ten)
- heavily based on semantics, very carefully worded

there's no best scale or way of assessing perception of effort
perceived exertion

are rpe ratings valid?

correlation evidence
- RPE as it relates to objective physical measure of exercise stimuli (not the physiological response, the physical exercise stimuli itself)
	- force, power output, treadmill speed, weight lifted [these are ABSOLUTE]
- if perceived exertion measures are related in a systematic way to physical measure of exercise stimuli, that proves its validity
	- RPE are valid bc they correlate with physical measure of exercise stimuli

most physiological responses to exercise are more strongly related to relative exercise intensity than the absolute intensity
- ie hormone responses to exercise
- usually measured as some percentage of some force (or as a maximum)

rpe is also related to the physiological responses to exercise
- this is bc heart rate is related to objective absolute physical stimuli (hr used as an index of intensity)
- correlated with physiological responses (which are validated on their relationship to the physical stimuli)

- moderators include
	- genetics
	- training (makes harder bouts after training feel like they're a lower intensity)
	- duration and mode
		- duration matters bc people may get fatigued over longer time periods

when people employ greater muscle mass, they have higher RPE

best study done on this (bc it's large)
- researchers looked at 2560 men and women; looked at perceived exertion, lactate, and hr in response to cycle/treadmill tests
- with hr, there's a strong correlation (.74) to RPE; it is a linear relationship
- lactate goes up in a curved linear (positively accelerating) fashion with re: to RPE (r = .83)

what this means in a practical sense
- once you get to a rating of 15 in RPE w/ re: to lactate, you're gonna have elevated blood lactate levels; you'll be above anaerobic threshold
- you can analyze this with a finger stick or just asking them!

experimental evidence
- manipulate the objective exercise stimuli
- best way this is done - studies that have people do a biking protocol that changes erratically (not progressive), people can detect that difference and rate RPE accordingly

hypnotism may affect RPE ?? (suggest perceived exertion changes in a way consistent with what they hypothesized)

ton of physiological experiments
- freeze red blood cells after taking it out (blood doping), increases vo2max
- epogec?
- what is normal hematocrit? (45 for women, little higher for men; can boost it to 60-something [dangerously high])
- what would happen to perceved exertion if you did blood doping?

fatigue responses to acute exercise duration
- what would happen to rpe in an experiment where you're going at a constant speed
- rpe is going to go up
- if you try to keep a constant RPE, speed is going to drop

[LOG]
- 32 pregnant women doing training beginning at the end of their first trimester (12 week)
- do weight training
- as they do more than 8 lifts at a certain weight, they increase weight the next session
- so what happens with training to perceived exertion
	draw a figure predicting the weekly changes in local (leg) percieved exertion associated iwth the 12 week so fleg curl training shown in the figure
	- over time, RPE stays the same bc with each week, they're getting stronger but the intensity is increasing each week


hypoxia - opposite of blood doping
- what happens when you go to altitude
- less oxygen, vo2max is reduced
- experiement - normoxia v. hypoxia; done in pittsburgh; breathing the gas from a huge balloon so the gas makes you feel like you're in denver or higher
- at any absolute workload, with hypoxia there's higher RPE relating to a workload
- but relative RPE is about the same? when put to a vo2 percentage of new min/max vo2
- it's gonna feel the same if you're going to the same percentage of your max effort

sodium bicarbonate ingestion
- buffers hydrogen ions
- what happens to RPE?
- just need to know main outcome
- in general, there's more dark points to the left (sodium bicarbonate means lower levels of hydrogen ions, causes RPE ratings to be lower)

[relative most strongly related to RPE]
summary of peripheral physiology mediators of exertion [relative]
< 50%
50 - 70%
> 70%
different contributions to how hard people feel they are working
- peripheral - afferents sensing muscle force and byproducts
- respiratory - respiratory muscl ean dlung afferents
- metabolic - percentage of vo2max - indirect - no receptor/afferents

- have people breathe a gas lighter than air, influences gas passing across vocal cords; in exercise test, suddenly it feels easier but only at high intensities bc of the work of breathing

summary
- RPE valid measure of exercise intensity bc
- look at slide

- CND correlates of perceived exertion
- we know much more abt the neurobiology of pain than perceived exertion
- we can test pain w/ animals (they squeak or recoil from pain)

graded signal from motor cortex - send signal based on how many motor units you have to lift

corollary discharge
- when you send signal to muscles to lift harder, gets sent back to cortex so you can see how much effort you're doing

curari - neuromusclar blocker
- if you use on muscles in experiments, it's gonna cause a loss in strength; you're gonna need increased central command
[LOG]
http://portal.coe.uga.edu
- course eval

- final covers head injuries, perceived exertion, circadian rhythms, sleep


curari partial block, blocks the central command signal?
- alpha motor neuron that synapses w/ the muscle
- central command signal will be graded based on how hard you're trying
- corticospinal tract will fire based on heaviness of load (this is signal going from motor neuron to muscle)
- there's a parallel signal being sent to sensory cortex (this is corrolary discharge), graded as well and sent as well, but goes to different part of brain (sensory cortex)

curari experiment
- administer curari until their grip strength is reduced by 25%
- this reduces the max signal you can send from brain
- this in turn decreases the corollary discharge signal
- would mean that you're not able to fully activate and you would have to "try harder" (send greater command signal, also means you're sending stronger corollary discharge signal too)

when they use curari and have to try harder to lift the same weight, this is perceived as more effortful BECAUSE they have to send a stronger corollary discharge signal
- the feedback signal (the dashed lines) represent afferent nerve from working muscle (ie golgi tendon organ), gives information about how hard the muscle is working; the same in BOTH conditions bc you're lifting the same amount of weight
- so you're only affecting signal for corollary discharge, not the feedback signal at ALL

afferent feedback evidence
- have people lift a weight and put an electrode on the tendon and vibrate tendon at a specific rate; increases afferent feedback
- people perceive this as harder despite no change in corollary discharge
- so BOTH of these things play a role

know candidate brain areas involved in percieved exertion!!!!

limitations for monitoring VO2
- expensive
- difficult to monitor directly

limitations of HR method
- counting difficulties - could potentially be several beats off; also baroreceptors at neck can slow down hr if you press down hard
- medication effects
- emotion effects
	- NTS - neurotractus soletaris, projects down to heart and controls descendign path ways to heart and can speed it way up
- position effects
	- heart has to pump against gravity (if ur standing); easier if you're swimming or in a supine position

limits of rpe method
- fuckin filthy liars [tell you it's less or more]
- psychopathology - can skew their reportings
- some will perceive exertion better than others
- graded exercise tests
	- different producing the same level of exertion as if someone just pointed it out to you
	- mode differences can vary perception
	- within three days of practice for people who have done it will be better at noting RPE (biggest errors on days one and two)

know the perceived exertion scale
- memorize the portion that has words
- how it relates to other measures of exercise intensity that are commonly used
- red box is commonly used for people that are trying to get fitter but aren't athletes
	- 40-84% of HRR
	- RPE is 12-16
- purple box is for athletes
- but the main box to know is the red one
- (but know both)

use of RPE in GXTs
- the very first stage of pretty much any protocol you use as a baseline to measuring
- helps you predict the cues for test termination
- helps you

----

circadian rhythm definsed
- creatures ahve evolved to funciton in the light dark cycle (as the sun moves)
- heart rhythm, breathing rhythm, menstrual "rhythm" are all driven by nerve tissue in body that's designed to produce the rhythm with different time periods

think of wave as body temp
- it fluctuates by a few degrees
- time dimension (period) and amplitude dimension (how much does it go up and down)
- half the distance between peak and trough is amplitude (trough = nadir?)
- healthy animals - normal amplitude; sick animals - attenuated amplitudes
- rhythm is marked by peak and a trough
- examples of circadian rhythms
	- temp when depressed - amplitude is despressed
	- rhythm is phase advanced (coming earlier than it should); out of phase with the light/dark cycle

you can mainpulate your sleep-wake cycle by phase shifts
- bright lights have a huge effect on shifting circadian rhythms

phase response curve [fundamental!]
- generated from data with hamsters
- ld - light/dark (lights on for 12 hours, off for 12 hours); dd - dark/dark (no light input, which is needed to amtch behavior to light/dark cycle)
- on the first day of dd, the hamster gets up later; gets up a little later each day

5 experiments with a hamster
- light pulse - turn lights on for one hour and turn them off
	- occurs six hours before hamster would normally get up
	- timing changes for each experiment (a - 6 hrs before) (b - hr before expected to wake, wakes up 1 hr later each subsequent day, a shift) (c - light pulse given 2 to 3 hours after it's woken up; greater delay in the time it gets up for subsequent days, a 3 hour phase delay); looking at phase shift in response ot the time you give the stimulus
	- phase advance means our body clock would move towards london (shift rhythm forward)
	- each experiment has an advanced portion and a delayed portion

-  brighter light leads to a bigger shift in rhythm
- phase shifts rely on time of day and magnitude of stimulus
circadian rhythm
- shifting hamsters' circadian rhythms based on when they pulse the light

human phase response curve for light and melatonin
- the rectangle is a sleep period
- dashed line is what happens with melatonin, dark line is light exposure (5000 lux of light)
- melatonin is a lot easier bc pills or liquid (yeet)
- re: melatonin, effects were shown given 0.5 mg melatonin
- you get bigger effects with light
- can't get big shifts with melatonin like you can with light
- dark line shows phase delay and phase forward
- you need artificial light if you want to shift (3-4AM for LA time)
- for melatonin, you get advance portion at 7 PM for getting up at 8 AM; delay maximizes more towards wake-up time (wh...at)

testing circadian rhythms
- swimmer test (bc of course it is)
- waking up in the morning, sleep related effects (joints stiff, dehydrated, no food) (POTENTIAL confounds) (when you sleep, your brain recovers but during the day it fatigues so it may be less fresh and may result in central fatigue)

circadian desynchrony protocol
- short days
- instead of living on 24 hour periods, you live on 3 hour periods (two hours awake and one sleeping)
- core body temp drops when you sleep
- confound effect of food is evened out
- all out 200 spring
	- 3 swims a day (3 days in a sun)
- you don't wanna swim at 5 in the morning
- best performance from 8-11 at night
- when body temp is warm, they did better

allison schmitt -
- swimming at 5 in the morning to 5 at night is 5.8 sec difference; 3.4% difference (it's a v large change)
- can you induce a phase shift to move to circadian rhythm that is better for performance

does exercise influence circadian clock
- done w/ hamsters
- phase shift - 8 hour phase advance (simulated jet-lag) for hamsters by turning off the lights 8 hours earlier
- control hamster reintrained and syncs with new light/dark cycle (takes abt 1 day per time zone you travel)
- going east is easier, west gives more jet lag
- other hamster was locked into a running wheel for 3 hours and made them run; causes a much sooner phase shift

benzodiazepines - used to shift hamster circadian rhythms and make them run in their wheels
- phase shift they get from drug doesn't happen if the animals can't run around

acute exercise can influence human circadian timing systems
- double plot (left side and right side are the same)
- on average, there's a small difference of about 20 minutes (our body operates at 24 hours and 20 minutes)
- you can exercise for 1hr from 6 pm to midnight, you will move your body clock towards europe (only 45 minutes, but)
- if you workout from midnight to 6 am, you move towards LA

[LOG]
- for phase advanced depressed patients, they would benefit most from exercising between 6 to midnight, which would phase shift them back (phase delay?) (am i understanding that right??)
- have to remember to induce a circadian phase delay, which means you're gonna be working out from midnight to 6 AM (so i had it backwards), this MIGHT help but nothing empiracally shows this
- what about melatonin? maybe like eight oclock at night to induce a phase delay

light + exercise experiments
- give light late at night 22:10 (10:10 at night), you get a delay
- phase delay of about an hour with light
- 90 min of running, 3/4 of hour phase delay (little more)
- when combined you get synergy!

chronic exercise effects on circadian timing
- active individuals with good vo2s; active and healthy, compared to controls
- put in room where they lost track of times (36 hours?); body core temp measured during that time, min temp marker of circadian phase
- active folks have mor enormal circiadian rhythms compared to odler folks who don't
- healthy ppl have big amplitudes (amplitude didn't differ)
- phase wasn't statisically significantly different but it was gettign there at least
- practical part? this is why older folks wake up too early

exercise induced increases in melatonin
- can cause your clock to time to a different time
- low intensity you might not get much effect, but you might in higher
- exercise outside also gives bright light (activating that sunlight response, so additive effect)
- serotonin nerves (studies w/ cats) release serotonin and medial raphe gets activated during walking in cats, goes to suprachiasmatic nucleus, induce phase shifts
- so 3 mechanisms
- exercise increases serotonin; stimulates release of melatonin; and sunlight if you're outside

- west to east had better winning percentage than east to west

1/10th of the ~1 million blind people in the US have no conscious light perception; body can't stay on normal light/dark cycle; operate on that 24.5 cycle; can't be affected w/ light, so use melatonin and exercise to keep them on track with the light/dark cycle

circadian rhythms

people who are totally blind live in a free running world (with no light input, have a slightly longer than average day)
- people w/ total blindness tend to be physically inactive
- their rhythm was something longer than 24 hours
- looking at quad strength, measured several times during the day; measured what time of day quad strength is highest; wasn't a stable time (progressively later); the controls tended to have a stable peak strength time
- tested six blind people
- did dominant and nondom
- two speeds
- people who are totally blind tended to show that peak quad strength was not stable but occurred later in the time of day when tested days later (~25 hour day)

- the only way to fix this is to take melatonin or well timed exercise

- older people have trouble waking up later (losing cells in superchiasmatic nuclei?); circadian clock doesn't tick as precisely
- rhythms may be shorter, causing them to wake up too soon

- depressed people can be phase advanced and have low amplitude rhythms

shift work
- bad for health
- having to constantly shift is BAD
- light and melatonin and exercise mayhelp people who have to transition into shift work

exercise + shift work
- simulated 8 hour delay in experiment, done for 8 days
- some were randomly assigned to exercise while some played cards; looked at who had big shifts in circadian rhythms
- exercise-  65% people had large phase delay; ie. this helped, but they didn't do vigorous exercise and many controls aren't shifting well

timing - forgotten dimension o fexercise
- time of day makes a difference!

- heart attacks don't occur evenly across the day (happen usually from 6-10 earlier in the day)

------------------------------------

sleep

[log]
the longest i've ever stayed awake is 23 hours
the longest i've ever slept is 14 hours
usual total amount of sleep time in a night is ~5 hours (weekdays) / ~8 hours (weekends)
i would like to get around 8 or 9 hours of sleep

the world record is 244 (some kid)
- muscle movement activates the brain and keep people from sleeping

animals will die sooner from sleep deprivation than they will from food deprivation
- if it's extended it'll be bad in humans.

sleep deprivation affects cognition

sleep - daily, reversible behavior involving disengagement from and reduced sensory responsiveness to the environment; occurs in a stereotypic posture and results in characteristic EEG patterns

- harder to fall asleep standing than laying down

Nathaniel Kleitman
- difference between REM and non-rem
- just about everything sleeps (maybe not fungi or mold but it's similar so fuck it)
	- rem - rapid eye movement
	- hypnic jerks; myoclonus - jerks that happen in REM sleep

william dement - father of sleep medicine

characteristics of REM
- brain is very active (like an awake brain while you're asleep)
- lose all tone in facial muscles except for the jerks
- dream sleep; when they hit rem and wake them up, there's a higher frequency of dream reports

rem sleep - brain basis
- triggered by the PONS
- sends signals to shut down the spinal cord
- within the pons there is the RPO/RPC, it produces REM sleep
- there are neuron that turn off REM sleep (dorsal raphe and locus coeruleus)

quite possible for exercise to impact sleep

non-rem
- specific eeg patterns associated with each stage of non-rem sleep
- deep sleep is better presumably; stage of sleep where it's hardest to rouse people

basal forebrain if stimulated can put people into slow-wave sleep
preoptic-anterior hypothalamus - temperature sensative nerves, help induce sleep
- exercise may help bc it heats up the body and induces sleep through those nerves

some nerves can wake you up
- to sleep well, you want a totally dark room; no audio
- ambien - sleep walking sort of?

if you consistenly take longer than 20 minutes, you are considered a heavy insomniac
- people fall asleep right into stage 1; progresses downward
- like a ladder
- the periods of rem get longer and longer over the night; more deep sleep earlier at night


the longer you're awake, there's more physiologically changes that lead to you wanting to sleep (more presure for you to sleep)

- slow-wave depends on how long you've been awake

sleep duration
timing of REM depends on the circadian system
- total duration does NOT rely on your prior sleep (or lack thereof)

study with no time piece
- sleep duration plotted against body temp
- go to sleep when body temp is low, you'll sleep v short
- go to sleep when body temp is high, you sleep for a while
- circadian system affects sleep duration

exercise affecting total sleep time , effects of exercise on first rem period depends on when you exercise (related to phase shift)

one reason we sleep is probably to help us think straight

in slow wave sleep, body temp regulation is turned off; so the REM sleep may be to help the brain from getting too cool (B])
pnea - refers to breathing
apnea - absence of breathing

apnea
- mostly older overweight men; the drive to breathe during sleep is reduced
- if you're always sleepy during the day time you may have sleep apnea
- sound-based tape recorder may help diagnose (picks up snoring

insomnia
- perseption of sleep is inadequate (not getting GOOD sleep)
- comorbid with mental health issues (doesn't link with ADHD), implies mental diseases are associated with arousal system that wakes you up (it's too stimulated)

too little or too much sleep is associated with dying (less than 4 or more than 10)
- 6.5 - 7.5 is the healthiest amt of sleep

greater death rates in the short sleepers

physical inactivity may be correlated with these short and long sleepers
- mortality higher for people who were inactive (nah shit)

[Log]
Does sleep influence athletic performance?
- yes; may not be mentally able to handle tasks if there's inadequate sleep; might fall asleep while doing an activity; may not have the energy to perform tasks (central fatigue from lack of sleep may lead to decreased physical performance);
- a lack of sleep would have a negative impact (acute effects)
- chronic sleep loss (negative cognitive effects and reaction times)
- might have a bigger effect for people with cognitive issues
- coaches can also be affected, making coaching mistakes

Thun - metaanalysis
- summarized 9 experiments, ppl randomly assigned to different amts of sleep
- suggests that one night of sleep deprivation reduces endurance performance, but no effect on the other types
- effects seem to be larger for evening tasks (sleep deprivation is going longer) [potentially reduced motvation?]
- small effect (quarter of a standard deviation)

stanford sleep deprivation
- no control group in the experiemtn (:/)
- have them extend their sleep for six weeks
- little faster, little more accurate, little better cognition
[there are no studies of chronic sleep deprivation on performance]

meta-analysis on acute exercise effects on sleep
- 41 studies; all went into sleep lab and had polysomnography done
- great majority of the folks did not have sleep problems
- what's the effect of a single bout of exercise on sleep?
	- all small effects (.5 standard deviations or more)
	- biggest effect on wakefulness after sleep onset (reduces it)
	- next is less stage 1 sleep and more slow wave sleep
	- 10 minutes more sleep
	- sleep efficiency improved - how much sleep you got / how much time you spent trying to sleep (higher number is better)
	- less REM sleep

moderate intensity acute exercise performed by chronic insomniacs can help sleep onset latency, perhaps by reducing pre-sleep anxiety adequately
	- people could get to sleep ~20 minutes faster
	- relatively few healthy treatments for doing so (exercise may be one)

clinicians generally get this wrong
- they say don't exercise right before bed and that's not riiiiiight
- evening exercise is not associated with poor sleep quality (but morning is the best)

- no difference if people did cycling hard or easy compared to being at rest
- experiments show that if you exercise in the evening it will not negatively affect sleep
- summary of acute studies
	- look @ the slide

cross-sectional studies show the odds of having symptoms of poor sleep are on average lower if adults are more physically active
- consistenly report good sleep
- 27% lower odds among physically active adults

effect size is larger for adolescents and younger adults; consistent effect, d = .89; true for athletes and non athletes (any PA is good)

data based on accelerometry
- actual relationship between how much PA people do and how well they sleep
- on average, the risk for often and always sleep was reduced by ~40% when people are meeting physical activity guidelines

hypopnea - really shallow breathing
are you being adequately oxygenated?

experimental evidence

- people randomly assigned to exercise conditions or not
- measured with polysomnography and questionnaires
- effect of exercise training on sleep?
	- sleep quality improved, biggest effect (self-report measure)
	- small effects on other aspects of sleep
	- no effect of exercise training on stage 2 or REM sleep in good sleepers (might not be true in poor sleepers but inefficient information)

what about the poor sleepers?

sleep apnea
- 5 randomized control trials
- 3 months to six months
- moderate intensity exercise training
- mean improvement averaged 6 fewer hypopneas or apneas per hour
- even people who didn't lose weight still had reduction in apneas and hypopneas
- could be attributed to either fat loss around neck or belly but may also be influencing the drive to breathe
- not better than cpap (continues positive airway pressure)

older adults with sleep issues
- randomly assigned to do exercise or not
- biggest and best effect size shown
	- record via diary (what time you go to bed and what time you get up, accurate if you take the time to do it)
- exercise showed improved sleep by 45 min to an hour, controls didnt change
- however, OUTDOOR EXERCISE, done in california; sunlight can have huge effect; adults can sleep poorly bc of light-dark cycles in their life

ideas abt how exercise could have effects
- doesnt necessarily help much for good sleepers, but may be beneficial for poor sleepers; suggests it can help
- can help induce phase shift
- reduce brain glial glycogen (may make you sleep more to replenish it)
- orexin - related tl sleep, exercise may help regulate it
- REM - regulated by PONS and neurotransmitters
- slow wave sleep - basal forebrain (don't worry abt gaba)
- reducing anxiety and depression may help sleep, links w/ exercise