I ordered the large and had to go down a size.  These bras are very comfy and could easily be work as sleep bras.  I originally searched for high impact bras for running.  These are NOT high impact.  I have to wear them with another bra for running or cardio.  I do wear them as they are for yoga or around the house.  I kept them even though they are not high impact because they work well for my non- cardio days.