Today my practice was: 3 rounds of Breath of Fire, 5 rounds of Alternate Nostril Breathing, and one — yes, one — Sun Salute. It was WAY better than nothing, I had no energy to move but I felt stiff and tired and I wanted to get rid of that. So I did it in a light, quiet way and it was great.
At the retreat they teach several ways to approach the poses. If you are feeling anxious/unbalanced, focus on breathing. If you are feeling aggressive/agitated, focus on stretching. If you are feeling lethargic, focus on strength.