After my terrible run on Wednesday (week 5 run 2), I had decided not to even attempt run 3 yet, and went out yesterday with my own music instead of the podcast, thinking I'd try and do 10 minutes twice, with a walking break in the middle, as a way of building up to it. So I set off, walked for 5 minutes and then started running.
Once I was going, it felt okay to begin with, so I started thinking maybe I would attempt the full 20 minutes after all. And once I'd made up my mind, I was very determined to actually do it. I didn't look at my watch (I dug out an old Garmin yesterday from a previous running life) until 14 minutes, when I was starting to struggle, and I was pleased I'd managed that. But then it got hard. Really hard. The last 4 minutes I was checking the time constantly, and it was only the thought of how annoying it would be to quit having done 18 or 19 minutes that kept me going.
So I made it, but as with the previous run, I feel I pushed myself too hard. I felt really ill at the end - dizzy, light-headed, I was worried I might even pass out. The 5 minutes walk at the end was a struggle again.
When I got home, I uploaded the data from my Garmin. My average heart rate across the whole session was 174bpm, which seems very high for a slow jog (and including ten minutes of walking). Just after I stopped running, it peaked at 196bpm (which is the highest heart rate I've ever recorded, beating 195 a few years ago). That's a higher maximum heart rate than you'd expect from someone my age, which isn't a problem in itself, but what is a problem is hitting my maximum heart rate as a result of very slow jogging, rather than all out sprinting. My average pace over the 20 minutes jogging was a very slow 14:30 minutes a mile (that's about 4.1mph for those who measure speed rather than pace), so it's not like I was going too fast.
I'm looking forward to getting back to intervals next week, but I need to think about what I'm going to do for the 3rd run of week 6, and then going forward. I might aim for 20 minutes again instead of 25, and see if it's any easier after another week of intervals. And then maybe repeat week 6 and do 25 minutes the second time around. I'll have to see how things go this week - I've read on here a lot of people unexpectedly struggle with week 6 run 1.