I recently ran a 1600m race in 4:49. This race was in 93 degree weather which is close to the 95 degree postponement temperature. I felt worse at the end running a 4:49 then I did when I ran a 4:41 PR at a normal condition race. Do you think that a 4:49 in very hot heat be almost equivalent to a 4:40 or so? Is it even possible to PR in such hot conditions?