Stand on one foot for half a minute, a hand on a chair if you need it, and put all your attention into the foot on the floor.

What the research says

A systematic review and meta analysis of tai chi, a practice built on slow weight shifting and balance, found it was associated with reduced stress, anxiety, depression and mood disturbance across randomised trials. The authors are clear about methodological weaknesses in the studies they pooled. Thirty seconds on one foot is not tai chi, so treat this as the same family rather than the same evidence.

Strength of evidence: one line of research. A single study, or a theoretical account.