Experiencing swelling of feet and ankles in very hot climate where we are working as volunteers in vietnam-- any suggestions please and thanks?

See below: You need to keep up your fluids and elevate your feet when possible , compression socks will also be of help.

Heat and gravity: You are in a hot geographic locale that you likely are unused to. Heat causes vaso-dilation widening of circulatory vessels, that with gravity tends to pool fluids in the lower extremities. If it does not abate after a reasonable time to accommodate, seek attention. Good luck!