T o wake each day in darkness is a plight you wouldn’t wish on your worst enemy, yet that’s what many of us do routinely throughout winter. Getting up in the dark decouples our life from our circadian rhythm (our body clock), with bodily processes such as cognition and metabolism put to work before they’re fully prepped.

Thank heavens, then, for sunrise alarm clocks. These “dawn simulation” devices glow with gradually intensifying brightness as your wake-up time approaches, kickstarting your circadian rhythm before you get out of bed. For many users, this results in a happier, healthier start to the day.

Sunrise alarm clocks can differ vastly – for instance, only some are bright enough to be medically certified as light-therapy devices for Sad (seasonal affective disorder) and other disorders.…