Week 7 fatigue, what's going on?

[u/inevitable_zest]

So as the title says, I've just finished week 7. But the last few runs I've really struggled more than before. I was finding running 20 minutes absolutely fine, my breathing was good and my legs weren't tired at all. I even went off the plan abit and built up to 25 mins gradually over a few weeks and felt great.

But now I start fine, then get to about 50-60% through the run and suddenly feel very fatigued. And my legs feel very tired. I'm not going any faster than I have been previously, in fact my pace is slightly slower. I still mange to finish the runs though. I even took a week off last week but it didn't seem to help.

What could be going on? I don't really understand why I'm suddenly struggling.

[u/AbundantHare]

I just finished W7D2 and it was really hard. I left a day between W7D1 and W7D2. I found the first run to be fairly easy and enjoyable - I could talk all the way through etc - but yesterday’s run was difficult. I was definitely struggling.

I did it in a hotel gym that was very hot, I only had six hours of sleep the night before and we had been travelling internationally with a time change. My average HR went from 122 on D1 of W7 to 135 on D2.

For me it’s a combination of eating poorly (unaccustomed diet at Xmas), plus the sleep, plus travel, plus the gym being so hot and also leaving just one day between the runs.

I am leaving the rest of the week before doing D3 and hopefully that will make a difference.

Good luck!