A bedside lamp before 10 a.m. improved activity and sleep patterns in 202 older adults

Key Findings

🧬 Fish Near the Poles Quietly Lost Their Body Clocks

• A genomic survey of 96 perch-order fish species found widespread, lineage-specific losses of core clock genes — concentrated in polar and deep-sea groups where daylight is seasonally absent or absent entirely.
• Three notothenioid species showed no circadian metabolic oscillations during late austral fall, including a sub-Antarctic species that sits outside the main cold-adapted radiation, suggesting clock loss happened early in the group's diversification.

🍽️ Matching a Mouse's Light Cycle to Its Own Clock Delayed Obesity by 8 Weeks

• Female mice fed a high-fat diet under a light-dark cycle tuned to their individual biological period — rather than the standard 24-hour lab cycle — showed obesity onset delayed by about 8 weeks compared to mice on the conventional schedule.
• The delay wasn't explained by eating less; locomotor activity stayed higher, pointing to energy expenditure as the likely mechanism. When the tailored light ended, the mice showed a stronger clock-shortening rebound than controls.

🌙 Evening Chronotype Is Strongly Linked to Gaming Disorder in Kids

• A cross-sectional study of over 30,000 Chinese children and adolescents found that evening-type individuals had more than double the rate of probable internet gaming disorder (11.8%) compared to the overall sample average (5.1%).
• Network analysis flagged tolerance, loss of other interests, and loss of control as the symptoms most tightly bridging chronotype and gaming disorder — and the pattern shifted across school stages, suggesting the relationship isn't static.

🦴 Two Clock Proteins Regulate Bone Breakdown — But in Opposite Directions

• Deleting one circadian gene (Per1) from osteoclasts in male mice increased bone breakdown and reduced bone mass. Deleting both Per1 and Per2 together produced the opposite: less bone breakdown and higher bone mass.
• Transcriptomic analysis showed the double-knockout cells downregulated a network of immune genes — some of which promote and some of which suppress osteoclast activity — suggesting PER1 and PER2 work as a coordinated system, not simple on/off switches.

👁️ Damaged Light-Sensing Cells in the Eye Are Linked to Disrupted Melatonin

• A systematic review of 10 human studies found that dysfunction in the eye's specialized light-sensing cells — which normally signal the brain's master clock — was consistently associated with disrupted melatonin patterns, including reduced output and failure to suppress melatonin when exposed to light.
• Advanced glaucoma and diabetic retinopathy showed the clearest circadian disruption. Mitochondrial optic nerve diseases, by contrast, left both cell function and circadian regulation largely intact — pointing to disease-specific rather than universal effects.

🧠 Morning Chronotype Was Linked to Lower Suicide Attempt Risk in a Genetic Analysis

• A genome-wide pleiotropic analysis found significant genetic overlap between 11 sleep traits and suicide attempts, identifying 32 priority genes enriched in metabolic, synaptic, and immune pathways.
• Among the directional findings: genetically predicted morning chronotype was associated with lower odds of suicide attempts. Thirteen of the 32 candidate genes were flagged as potentially druggable, including five with existing approved drug interactions.