Cortisol and Sleep
Sleep Quality Impaired by Increased
Cortisol Levels.
The adrenal glands are
situated on top of the kidneys, the particular
segment of the adrenals of interest here is the adrenal cortex
where the synthesis of cortisol from cholesterol takes
place.This is a vital hormone that is often referred to as the
"stress hormone" as it is involved in the response to
stress.
Cortisol
regulation during the sleep wake
cycle
The amount of cortisol present in the serum
undergoes diurnal variation, with the highest levels present in
the early morning, and the lowest levels present around
midnight, 3-5 hours after the onset of sleep.This applies to
those individuals who have regular sleep wake cycles. The
secretion of cortisol is regulated primarily by the
hypothalamus and anterior pituitary gland. Information about
the light/dark cycle is transmitted from the retina to the
paired suprachiasmatic nuclei in the hypothalamus, see diagram
below.
Suprachiasmatic Nuclei
Stress and Serum
Cortisol Levels:
Serum cortisol levels have been observed
to fluctuate in connection with abnormal ACTH levels,
clinical depression, psychological stress, and such
physiological stressors as hypoglycemia, illness, fever,
trauma, surgery, fear, pain, physical exertion or extremes of
temperature. Cortisol secretion appears to be an important
requirement for mounting a response to stress.
Coping with stress is a necessary part of
modern day living, since it's almost impossible to avoid
stress, it is of paramount importance to control the reactions
to stress and so maintain healthy levels of serum cortisol.
High levels of cortisol result in hyperglycemia, this is fine
if the individual has to cope with an emergency, for the extra
glucose provides a ready source of
energy. However, prolonged stress may cause
hyperosmolality resulting in disturbed electrolyte balance and
brain function.
Increased cortisol secretion from prolonged
severe stress can suppress the immune system which may lead to
tissue destruction, and the initiation of an autoimmune
reaction.It lowers bone formation thus favoring development of
osteoporosis in the long term. Prolonged exposure to cortisol
causes damage to cells in the hypocampus resulting in impaired
learning. Excess cortisol decreases protein synthesis,
increases protein degradation leading to muscle wasting,
and interfers with skin regeneration and wound
healing.
How to avoid high
cortisol levels during sleep:
Both the quality and
quantitiy of sleep determine cortisol levels, researchers
have found that impaired sleep results in increased
cortisol levels, and decreased levels in growth hormone. The
drop in growth hormone is associated with an increase of fatty
tissue, weakened immunity, and a decline in general health. As
people age sleep quality and quantity is diminished, and
cortisol levels increase, this results in a compromised
immune system which may be the cause of many diseases
associated with aging, including impaired memory.
Following a healthy diet, eating a small
protein carbohydrate combination snack before bedtime, some
form of moderate exercise at least 1 hour before bed, and
excluding any form of caffeine after midday. Over indulgence in
coffee can contribute to high cortisol levels.
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