My recent experience suggests that if I stand on one foot until it becomes slightly difficult about four times/day I will sleep much better. Two days ago I measured how long those four bouts of one-foot standing actually were: 6.2 (left foot), 4.3 (right), 4.8 (left), and 5.2 (right) minutes. The median is 5.0 minutes. When I started doing this, about two weeks ago, each bout was about 2 minutes.
It doesn’t seem to matter when I do them. Now I do two in the morning and two in the evening. Fits perfectly with a subway commute. You’ll want to be forced to stand.
In the evening I have a pleasant sense of anticipation: I will fall asleep and wake up feeling really good. I have never before felt this way. I have slept this well before, when I stood 9 or 10 hours/day. The sheer difficulty and all-consumingness of doing that, I now realize, got in the way of anticipating the benefits.
Something else curious is that one-foot standing leaves no mark — I can’t tell at 3 pm how many bouts I’ve done so far just by noticing how I feel. Unlike water or calorie consumption: If I don’t drink anything I’ll get thirsty. If I don’t eat anything I’ll get hungry. But if I don’t get enough of this particular byproduct of exercise I’ll never notice.