Today I did the first 5K in a while—I had gotten used to being tired before, but, perhaps because of consuming caffeine this morning (causal link not verified), and because of losing a bit of fitness since before, I felt some considerable strain on this one, and my heart ached a little as I ran. It was good at the beginning, but I progressively became noticeably slower and my legs became more strained as well. Overall, considering all this, it was a good time, and very close to my PB, but given how the two main limiting factors were heat and the aforementioned heart discomfort, and I'm ostensibly not at the peak of fitness at the moment, it's evident I still have a long way to go. If I haven't mentioned before, I'm aiming at some point for sub-20, so clearly I've a lot of improvement to do yet!