Sleep Consistency & Mood

On Sunday, we spring forward and advance our clocks one hour for Daylight Saving Time.

Sleep consistency and sleep duration are both important to maintaining well-being.  Prior research demonstrated that disruption to the circadian rhythm, the internal time-keeping system, was associated with poor mental health in a study of over 90,000 people.

The first year of practical medical training after medical school (internship) is known for an abrupt escalation in workload, shifting schedules over a 24-hour day, and an increase in depression in interns.  Researchers examined the sleep schedules of 2,115 doctors, for their entire internship year, assessing their sleep with a wearable device, their mood with a smartphone app, and depression using a 9-item questionnaire. 

The demanding intern training year is notorious for its irregular schedule.  Reduced total sleep time, later bedtime, and increased variability in bedtime and wake time were all associated with more depressive symptoms.  Increased total sleep time, earlier bedtime, later wake time, and less overall variability in sleep patterns were associated with better next-day moods. 

Inconsistency in sleep patterns, when the interns went to bed and woke up, substantially impacted mood and depression.  This study suggests that mental health can be improved with both an adequate amount of sleep and regular bedtimes and wake times.

Takeaway:  Stability of your sleep-wake schedule contributes to improved mental health.  Consider a wearable sleep tracker to help improve this important habit. 

Perhaps it is finally time to stop changing the clocks twice a year with the Sunshine Protection Act of 2021, which proposes maintaining Daylight Saving Time.

Source

Srijan Sen et al., Day-to-Day Variability in Sleep Parameters and Depression Risk: A Prospective Cohort Study of Training Physicians, npj Digital Medicine, Feb. 18, 2021, https://www.nature.com/articles/s41746-021-00400-z.

Sunshine Protection Act of 2021, https://www.hydesmith.senate.gov/sites/default/files/2021-03/Sunshine%20Protection%20Act%20of%202021.pdf.