Traditionally pranayama is done early in the morning, before other activities. Classically, just before sunrise. Early, even if not precisely at dawn, is idea time in which we can be free from most daily interruptions. Another important note is that our minds are less cluttered with the events and preoccupations of the day. Our body may be a little stiff, but potentially neutral.
Pranayama at this time offers a clear start to the day, a moment to be self reflective and to set up good patterns of breath and mindfulness for the next 24 hours. It gives us an idea of how we actually are, as it helps us become aware of the effects of our activities the day before and to undo any remaining imbalances.
During a session of pranayama we may notice, for example, that we feel a bit jangled from too much coffee the previous day, are heavy in the body from slow digestion or are full of leftover thoughts that are still worrying us. Taking 15 or 20 minutes for pranayma can help us regain equilibrium. It also enables the body to function more efficiently on an organic level by opening the chest and lungs, stimulating the diaphragm and facilitating digestion and elimination.
The end of the day is another possibility, and for some is more feasible. There may be a degree of end of work lethargy or tiredness but some people clearly function better at this point of the day. If we are able to bring the mind to quietness and receptiveness, the body is often looser by the afternoon and the ribs and chest are more pliable. Pranayama at this time of day can be soothing and refreshing.
Given the possibility, a “perfect” yoga day would be: early morning pranayama followed by a break of half an hour followed by an asana practice.
A clean and quiet place where we can remain undisturbed for the duration of the session is best. It takes a little time to settle into the neutrality and stillness required for clear breath observation. It is difficult to break off and then try to come back to where we were or need to be. Plan a shorter session if necessary but endeavor to keep the time free of distractions.