Surprising increase in Pace

Hi guys,

I‘m currently experiencing something that surprises me:

I‘m into structured training (I mostly use running/uphill running/trailrunning for mountaineering training) for around two years now (with breaks) and bring the following facts with me: 32yo, Max HR 196, aeT 160, anT 176 – lab tested.

I had to decrease training load by 50% at average during the last 5 weeks due to two sicknesses our 3 year old brought home.

After that our second child was born and I began to increase the load again (3 weeks back) starting from about 6 hours with an increase of 10% each week. At the end of last week (week 2) I did a really demanding Intervall session (6x 4min running up to upper Zone 4) and rested for full two days. I started week 3 with a one hour fartleg-like run in Zones 1+2 with some kilometres in fat max zone and some close to aeT. I felt amazing (though overnight recovery is not too good with a newborn at home!). I breathed very easily up to aeT (and would have even beyond that probably) and my paces at all heart rates were significantly higher that anytime before. Before that pace at aeT or just below was around 05:25 or 05:30 min/km (at 155-158bpm). Now I’m able to run a 5:05 pace at 156bpm.

At first I assumed there’s an error with some sensors but was able to exclude that as this is my favourite trail that I know really well and I even stopped for some seconds and cross checked the heart rate the chest belt recorded.

The next night was busy with the baby and I didn’t get much sleep which is why I decided to go for a 40 minute recovery run on the next day and do my long run at another time. The result was similar. Normally I would do these runs well below 140bmp (End of Zone 1; Physicians advised to use anything below that as recovery which I do and find useful) at a pace of around 06:45 min/km with a HR of 135. Now it was 6:16min/km at 135bmp at average.

Has anybody an idea on how that happens? I thought that maybe There’s something wrong with my systems but I’m just feeling so good that I think this wouldn’t be the way my body would tell me so.

I think it’s great but I think I have gained a basic understanding of how training works and this is just very contradicting to anything I think I knew.

Thanks and KR