i have speedplays also, and i sometimes get hotfoot when it's over 110 degrees outside and over a 15 mile ride. i just loosen up the straps a little and wiggle my feet left and right, pull up on the pedals instead of push down, and the hotfoot dwindles so i can continue my ride.

i used to get it constantly when i had mtb shoes and pedals, but with my zeroes, hardsoled sidi genus 5.5 shoes and lightweight socks i only get it when i should - like when its way hot.