Garmin has announced the Vivoactive 6, a new GPS fitness watch with a slimmer design and brighter display.The Vivoactive 6 comes with a long-awaited smart wake up alarm, which monitors sleep stages and wakes the user up in a light sleep stage.It offers a full range of sleep and activity tracking, supports over 80 sports, and includes advanced running dynamics for better training insight.The Garmin Vivoactive 6 is compatible with Android and iPhone, and will be available in four colors starting from April 4.