Living a structured life with regular meal times and early bedtimes can lead to a better life and perhaps even prevent the onset of mental illness, suggests a study.
Our daily sleep-wake cycle is governed by an internal 24-hour timer — the circadian clock.
“However, there is evidence that daily activity is also influenced by rhythms much shorter than 24 hours which are known as ultradian rhythms and follow a four-hour cycle,” explained Kai-Florian Storch from the Douglas Mental Health University Institute and McGill University in Montreal.
Most prominently observed in infants before they are able to sleep through the night, ultradian rhythms may explain why, on average, we eat three meals a day that are relatively evenly spaced across our daily wake period.
These four-hour ultradian rhythms are activated by dopamine, a key chemical substance in the brain.
When dopamine levels are out of balance, the four-hour rhythms can stretch as long as 48 hours.
In the new study conducted on genetically modified mice, Storch and his team demonstrated that sleep abnormalities, which in the past have been associated with circadian rhythm disruption, result instead from an imbalance of an ultradian rhythm generator (oscillator) that is based on dopamine.
The new data suggests that when the ultradian arousal oscillator goes awry, sleep becomes disturbed and mania will be induced in bipolar patients.
Oscillator imbalance may likely also be associated with schizophrenic episodes in schizophrenic subjects.
The findings have potentially strong implications for the treatment of bipolar disease and other mental illnesses linked to dopamine imbalance, the authors noted.
The study has been published in the online journal eLife.