I have the "bad" habit of comparing myself in the present and in the past and, of course, the conditions, the age and the situation are not the same when it comes to running.
Today, I started the run calmly, I even made up my mind to stop myself if I saw that I was speeding up, so the plan was to run around 5'/km on average...
I have started well even a little slower during the first two kms.
However, one thing is the will and another thing is what my legs want to do... from the second km, when my body was already fully warmed up, my legs wanted to find their "natural frequency" of performance which, much to my regret, does not mean maintaining a cruising speed above 5'/km but rather going faster, around 4'40"/km where they are better at a "mechanical" level, which is not the case at the respiratory level because my lungs, heart and other organ and cells involved in the respiratory process are not yet at the point of operation that my legs require...
Result?
8 km in less than 39' and average heart rate too high to consider this training as "soft"...
Actually, not long ago, running at 4'30"/km meant a comfortable Run for me... obviously, my weekly volume of training at that time was much higher than what I currently achieve, and consequently, my body is at a lower level of performance although it may not seem so for my legs that are not comfortable going so slow...
I'm sure I can gradually increase my mileage and gain better aerobic conditions quickly. Also, we all know that the runner's performance in summer is not so good compared to the cold season...
Still, a lot to improve...
@toofasteddie