At night, in a state of sleep, the reverse should be happening.
Sleep is vital to human functioning. Mammals deprived of sleep over two to three weeks die. Insufficient sleep results in the type of cognitive impairments that lead to all manner of accidents - motor vehicle, on-the-job, personal relationships.
On falling asleep, healthy adults enter non-REM (NREM) sleep, a period of rest and energy conservation. The brain literally cools, while heart rate and other physiological processes slow down. The eyes move slowly, and the muscles are relaxed. The brain progresses through four stages of NREM sleep (the latter stages characterized by slow delta wave activity). NREM sleep predominates during the first part of the night.
NREM sleep and thermoregulation are intertwined. Thus, a warm bath at night promotes NREM sleep.
REM (rapid eye movement) sleep, which is concentrated in the hours before waking, is far more noisy, marked by intense mental activity, vivid dreaming, and high brain metabolism. Paradoxically, while the brain is partying, large muscles are virtually paralyzed.
Goodwin and Jamison point out that too much or too little sleep is a feature of both depression and mania. They also mention that vital research is lacking, and therein we are faced with a series of chicken-and-egg conundrums. On the “chicken” side, a malfunction in the master clock may throw our other clocks out of phase, including those that regulate our moods. For instance:
We know that a disturbed night’s sleep is the royal road to mania. We also know that sleep deprivation is also the quickest way to bring a person out of depression, albeit temporarily.
There is a strong body of opinion that posits that those of us with bipolar are “phase-delayed” in our sleep cycle. In other words, it appears that a good many of us prefer to go to bed later and wake up later than the rest of the world.
Bipolars may be more sensitive to subtle disturbances in the master clock, borne out in research that shows our population is more susceptible to seasonal affective disorder than the general population (think of seasonal adjustments as a ‘very long” circadian rhythm).
