I've been experimenting with running at different times of the day (well, whenever I can fit one in basically!) and I've found that I tend to have more energy and ability late morning but whenever I attempt a run at, say, 3 or 4pm, I can't keep going! It's noticeably different. Or maybe I am still not back to normal after my virus. Last Sunday, I ran 5K at 1pm and coped fine, then on Tuesday I tried running a shorter distance (3 or 4K) and had to stop after 5 mins as everything hurt!
Can't make head nor tail of it!