After 90 minutes, people felt less energetic and more anxious or sad—and drinking water picked them up. After 180 minutes, volunteers allowed to drink water did better on a series of memory and attention tests. Take a walk, ideally near greenery. In a much-noted study, scientists gave volunteers tests of their attentiveness and mood before and after a 50-minute walk through a leafy area at Stanford. They did better after the walk. But volunteers who walked beside a busy multi-lane highway in Palo Alto didn’t do as well.
