Scientific Papers and Revision Lecture Flashcards
What study explored sleep deprivation?
What were the findings?
Rae et al 2017
- caused a decrease in PPO
- Caused increased sleepiness
- Decreased motivation to train
What is non-functional overreaching?
When the individual is rested but the performance has no improvement after resting
What is functional overreaching?
After the rest, able to recover and perform well
What is overtraining?
Training beyond the overreaching threshold causing a decrease in performance after training.
A long recovery period is needed to recover from the effects of overtraining
What study investigates the release of Growth Hormone?
What were the findings?
Kanalay et al 1997
GH concentrations were greater in the delayed and sequential exercise bouts compared to the control groups
There was no differences in the GH release during sleep
Circadian Timing of:
a) Melatonin
b) CBT
c) Cortisol
a) Rises at dark onset - peaks at 2-4am
b) CBT gradually rises during the day - peaks at 6PM
c) Cortisol climbs gradually and peaks at waking time
- Has a high degree of impact relating to stress
Chronotype influence on Sleep duration
(Work vs Work-free days)
Early Chronotype
- More sleep during work days
- Less sleep time during work free days (due to social activities)
Late Chronotype
- Less sleep during work days
- More sleep during work free days (to recover from sleep debt)
What is the Primary Zeitgeber to circadian rhythm?
Light
What is the photoreceptor that is sensitive to light?
Melanopsin - blue light triggers the melanopsin cells
What controls the release of Melatonin?
Pineal Gland
How does light impact on alertness and mood?
(Hormone related)
Light causes the SCN to supress the pineal gland and supress the melatonin secretion
Supression of melatonin causes an increased alertness and mood
Resting the clock
How long does it take to synchronise the peripheral clocks?
4-12 hours
What is the basis of the 24 hour rhythm
(4 words)
Transcriptional-Translational Feedback Loops
What does daylight do to clock genes?
Causes the expression of the Per and Cry genes to activate the transcriptional-translational process to increase the protein synthesis
What does nighttime do to clock genes?
Dark onset supresses clock gene expression to allow the body to prepare and rest/recover
Blocks the Clock:BMAL1 transcriptional activity to allow for sleep to occur
3 Features of the molecular clock
1) Entrainment - to the light dark cycle
2) Endogenous pacemaker - Clock internal to organism
- Can keep time without the presence of external cues
3) Temperature compensation - not affected by external changes in temperature
What is the phase angle of entrainment?
What chronotype has a larger angle of entrainment?
The time interval between the timing of the body clock (DLMO) and the timing of an external cue (e.g. Mid sleep time)
Early Chronotypes have larger angles of entrainment due to earlier DLMO
What study looked at the time of day variation in sports performance?
What did it show?
Facer-Childs 2015
Early Chronotypes Performed best 6 hours after awakening
Late Chronotypes performed best 12 hours after awakening
When is the biggest loss in height and how much height do you lose within 3 hours?
Biggest loss in height occurs in the first hour (50%)
80% loss in height within 3 hours
What time is the greatest trunk flexibility?
PM
Who conducted the study ‘Time of day variation in VO2max’
What were the findings?
Knaier et al 2019
There is a diurnal variation to VO2 Max - 4-7pm was the peak in VO2 max
The diurnal variation was 2.5 times higher than that of the day to day variation in VO2 max performance
Is AM or PM better for lifting larger loads?
PM you can lift heaver loads however fatigue faster
What time does cough and dyspnea worsen?
Approx 4am
When should you take short acting statins?
In the evening
