Evening Routines that Effect Your Mortality Risk

This simple change could be the difference between living long—or not living at all

Author

My Longevity Experiment
April 10, 2025

The Link Between Circadian Rhythm Disruption and Early Mortality

Too much exposure to artificial light at night, combined with insufficient daylight during the day, may significantly increase the risk of premature death. This new research highlights the vital role of circadian rhythm and sleep health in determining long-term well-being and survival.

Subscribed

Modern lifestyles often break the natural cycle of light and dark. Night shifts, late-night screen time, and working in enclosed environments with limited daylight contribute to this imbalance. The consequences, according to an international team of researchers, could be deadly. The study builds on existing evidence linking artificial light exposure to serious health conditions.

"Exposure to brighter nights and darker days can disrupt our circadian rhythms, a disruption that is known to lead to various health issues including diabetes, obesity, cardiovascular disease, mental health issues and increase the risk of death," says the study's senior author and sleep scientist Sean Cain, from Flinders University in Australia.

"These new insights into the potential adverse impact of light have shown us just how important personal light exposure patterns are for your health."

The study analyzed data from the UK Biobank, reviewing records of 88,905 participants who wore light sensors for one week. These individuals were then followed for around eight years. The data revealed that exposure to high levels of night-time light was associated with a 21 to 34 percent higher risk of death. Conversely, high levels of daylight exposure were linked to a 17 to 34 percent lower risk of death.

While the study does not establish direct causation, the correlation between disrupted light cycles and increased mortality risk is significant. It strengthens the argument that circadian rhythm disturbance can contribute to disease development and shortened lifespan.

"Protection of lighting environments may be especially important in those at risk for both circadian disruption and mortality, such as in intensive care or aged-care settings," says lead author and sleep scientist Daniel Windred, from Flinders University.

Further computer modeling indicated that the strength and regularity of participants’ circadian rhythms, likely shaped by their exposure to light, were directly related to their mortality rates. These findings suggest that maintaining a healthy light environment supports the body's natural rhythm, which in turn may protect against chronic diseases and early death.

Despite the concerning implications, the solution is straightforward and accessible. Increasing exposure to daylight and reducing artificial light at night can significantly support better health.

"Our findings clearly show that avoiding night light and seeking daylight may promote optimal health and longevity, and this recommendation is easy, accessible and cost-effective," says sleep scientist Andrew Phillips, from Flinders University.

Your call to action for circadian rhythm and mortality risk

To support your long-term health, make intentional changes to your light environment. Prioritize spending time outdoors during daylight hours, especially in the morning. In the evening, reduce exposure to bright and blue-toned light by dimming indoor lighting and limiting screen time. Consider blackout curtains or sleep masks to ensure complete darkness at night. By aligning your lifestyle with your body’s natural rhythm, you may not only improve sleep quality but also lower your risk of developing serious illnesses and increase your chances of living a longer, healthier life.

Study Links: