Organizers of the St. Jude Rock n' Roll Marathon have moved the race's start time up earlier due to expected high temperatures.
Because of the heat, the start time will now be 6:45 a.m.
The course takes thousands of runners past several Nashville landmarks, with live music throughout the trail.
Organizers said this weekend will be all about watching out for the heat. Temperatures are expected to hit the high 80s which can be costly for the many runners hoping to make a new personal record.