Health Capsules

Sleep trackers and clinical sleep studies serve different purposes in understanding rest, fatigue, and possible sleep disorders. Readers will learn how consumer devices estimate patterns, how laboratory studies measure sleep and support diagnosis, and how to judge when self-tracking is sufficient versus when professional assessment is warranted.

Your daily rhythms are set less by habit and choice than by the natural light-dark cycle, which resets an internal clock deep in the brain. Morning sunlight and dim evenings keep sleep, mood, and metabolism in sync, while artificial light at night throws them off. Align your day with these light cues and you can sleep better and lower your risk of metabolic trouble.