How stress causes lack of sleep
Stress activates the HPA axis:
Stress —> CRH —>ACTH —>increases Cortisol
Normally:
•Cortisol is high in the morning
•Low at night (to allow sleep)
•Under stress:
Cortisol stays elevated at night
Increases sympathetic activity (increases adrenaline, noradrenaline)
Result:
•Difficulty falling asleep
•Fragmented sleep
•Reduced REM & deep sleep
How lack of sleep itself causes stress
Sleep deprivation is interpreted by the brain as a threat.
Lack of sleep leads to:
•Increased Cortisol (especially evening cortisol)
•Increased Sympathetic tone
•Decreased Parasympathetic (vagal) tone
Neurochemically:
•Decreases GABA (calming)
•Increases Glutamate (excitatory)
•Increases Amygdala reactivity (emotional stress)
Result:
You feel more stressed even with minor triggers
Hormonal consequences of chronic stress + poor sleep
On reproductive axis (HPO axis):
Cortisol suppresses GnRH pulsatility
•Decreases FSH & LH
• Anovulation
•Irregular cycles / amenorrhea
(This is functional hypothalamic dysfunction, not PCOS)
On metabolism:
•Increases Insulin resistance
•Increases Ghrelin (hunger)
•Decreases Leptin (satiety)
-Weight gain or metabolic dysregulation
-Can worsen PCOS if already present.
MBH/AB