A blood flow stimulating device comprising: a boot (101) comprising a sole (111) and an uppera sock (11) disposed within the boot (101) and a bladder (19) disposed within or on the sock (11) wherein the bladder (19) is configured to undergo repeated inflation and deflation so as to stimulate blood flow in a wearer of the blood flow stimulating device wherein the sock (11) further comprises a toe region (1002) a heel region (1001) and a raised portion (1003) between the toe region (1002) and the heel region that (1001) in use reduces the distance between the sock (11) and a foot of a wearer of the blood flow stimulating device at the raised portion of the sock.