If you have ever taken a long flight or worked a night shift, you know the feeling of being moody, fatigued or unfocused.
These changes stem directly from disruptions to your body’s natural sleep-wake cycle. Circadian rhythms are 24-hour internal cycles that regulate body temperature, hormone production, sleep and activity levels. A disrupted circadian rhythm can significantly elevate the risk of mood disorders such as depression and bipolar disorder.
While earlier research relied heavily on small sample sizes and self-reported sleep data, recent studies present far more compelling evidence. Research reveals that individuals with disrupted rhythms — such as those who remain active late at night or inactive during the day — experience higher rates of mood disorders. Furthermore, these disruptions are linked to lower overall well-being, impaired cognitive function and slower reaction times.
These findings support the idea that disturbed circadian rhythms are linked to poor mental health. Crucially, they demonstrate that simple activity tracking could serve as an effective early detection tool to identify individuals at risk of depression or bipolar disorder before symptoms escalate.
In our modern society, this problem is growing rapidly. Artificial light, particularly at night, severely disrupts our internal clocks. Moreover, life in urban environments constantly exposes millions of people to pervasive light and noise pollution, fragmenting sleep patterns and destabilising mood. As global urbanisation accelerates, more people will live in cities, significantly heightening the widespread risk of circadian disruption and the mental health challenges that follow.
While we have long understood the importance of sleep for physical health, science now confirms that it is equally crucial for mental health. Understanding and protecting our circadian rhythms must become a priority in preventing and managing depression, chronic stress, and mood volatility. Prioritizing healthy, consistent sleep habits is no longer a luxury; it is an essential foundation for our overall well-being.
Student, Mount Kenya University, Thika Campus
Bachelor of Arts in Mass Media and Communication.
