Susan , I asked my friends about your question and this was their thoughts.
Thanks team, some interesting thoughts. Firstly let’s confirm that it is the heart that pumps the blood around our bodies. In a normal situation the heart is strong enough to pump the blood up to our head, so it might find it easier to pump the blood to our head when we are upside down. Any idea why? Think of gravity.
When you are doing a headstand the heart will not need to fight gravity to get the blood to your head, so it might find it a bit easier. It does however still need to get the blood to your feet (which are now above your heart) but it is strong enough to do this.
There might be some visible signs in the way the blood circulation changes. If blood has a little difficulty getting to the feet they might go a little pale. If the blood does not leave the head as quickly as usual, the face might go a little red. You might also get a change in the pulse rate if the heart has to work harder. These can all be tested with a healthy volunteer.