8. Sleep Flashcards
Delayed phase shift
Vs
Advanced phase shift
Delayed phase shift
- westward travel
- owls: more susceptible to melatonin suppression and delay due to evening light
Advanced phase shift
- eastward travel
- larks: more susceptible to desynchrony due to morning light, shifts to waking earlier
SCN clock duration and reset
Most people have SCN clock 24h 8 min (delayed phase shift shift)
In general, SCN needs to be reset forward (advanced) or backward (delayed) by 5-15 min/day
If shorter than 24h, advancement if 10 min or less needed
Eg delay exposure of morning light by 10 min it ideal wake up time
If longer than 24h, backward setting of 20 min or less needed
Eg limiting light 20 min earlier in evening so ideal bedtime can be achieved
Causes of secondary insomnia
Vascular dysfunction (peripheral hypoperfusion, vasospasm)
Visual impairment (opacification, retinal degeneration)
Renin-angiotensin dysfunction (fluid balance)
Effects of impaired sleep quality and duration on food intake
Lower day leptin
Higher intake of carbohydrate dense foods
People who slept 4h for 5 nights in a row - sought 300 calories more, esp from sat fat
