BusinessA week in the 5 a.m. club04:53This browser does not support the video element.BusinessMalte Rohwer-Kahlmann02/11/2020February 11, 2020Whether it's checking off your to-do list while the rest of the world sleeps or reading a book in 15 minutes, apps and life hacks promise to make you happier and more productive. But do they work?Copy linkAdvertisement
