How Stress and the Circadian Rhythm Affect Sleep

15 Apr How Stress and the Circadian Rhythm Affect Sleep

Our circadian rhythm is crucial for initiating and ending sleep for us and one contributing factor is the sunset and sunrise, respectively. A recent study performed in Japan at Nagoya University has found another factor that affects this cycle and can impede it’s effectiveness. This factor is stress.

The circadian rhythm is a 24 hour oscillation with brain’s suprachiasmatic nucleus (SCN) neurons regulating the sleep-wake cycle. In events that are life threatening, this rhythm can be shut off to prevent the mammal from sleeping to ensure its own survival. This shut off is usually temporary but if it is extended for prolonged periods of time, other issues may arise such as insomnia and other sleep disorders.

The study looked at links between the circadian rhythm, stress, and wakefulness in mammals (specifically, mice). Researchers looked at the corticotropin-releasing factor (CRF) neurons, which are known to play a role in stress response, and how these neurons affected sleep and wake once activated.

The results showed that when these CRF neurons were active, the mice were awake and much more active than usual. Furthermore, the opposite was true for when these same neurons were inhibited; the mice showed reduced locomotor skills and wakefulness. The team concluded that neurons in the SCN control the activity of the CRF neurons which, ultimately, regulate the sleep-wake cycle.

Implications of the current study hope to add to the already growing body of research in sleep disorders and with this new pathway discovered, potentially offer another way to help reduce the prevalence of sleep disorders and improve overall sleep quality.