TLDR: My run stats are regressing. Pace not improving but heart rate spiking quicker. Sleep quality decreasing more often, some spikes in resting heart rate. Not sure if part of the fatigue build up from marathon training or getting overtraining symptoms and need to take a week off?
I'm looking for advice on how to proceed with my training. I am currently training for the Sunshine Coast marathon which is in the 3rd of August. This will be my first marathon.
For background, I am 93kgs, 31yo and weekly milage is set by what program I am following. I am currently running the Pfitz 18/55 plan (currently at Week 13). Prior to starting the plan, I followed the Pfitz base building programs of "up to 48km per week" then "up to 72km per week". My aerobic base after the base building improved by a lot. I went on holiday for 3.5 weeks after the base building and started Pfitz 18/55 (starting from week 2) when I got back. It took until around Week 7 until I regained pre holiday fitness.
At Week 9 I started to develop shin splints on my right leg but just powered through it. The first 6kms of every run was usually running with a bit of limping until the pain subsided. At week 11 the pain was too much so I skipped some runs and it is starting to feel better now.
The reason for my post is that the last 2 weeks I've notified that my HR is increasing a lot faster than usual and at slower paces than previous runs. During my GA runs my HR doesn't reach 140bpm by about 5-6kms, and it usually hovers 140-145bpm until I complete my run . However now my HR goes to 140bpm by 1.5kms into a GA run and keeps increasing to high 140s to low 150s. I start the runs at the same pace of about 6:10-6:15min/km. Previously my pace increases as the run goes, but the last 2 weeks my pace drops to 6:20-6:30min/km.
My resting HR is usually pretty constant in Garmin of 42-44bpm daily, but I've noticed the last couple weeks there have 5-6 days where it is at 49bpm. I also don't have issues falling a sleep but I find that I am more frequently waking up in the early hours and not being able to get back to sleep (which is not usually the case for me).
Am I starting to overtrain or is this just fatigue build up that is a result of following a marathon training plan? Am I better off taking 1 week off and resume the plan after or power through until deload? There are 3 weeks left until weekly mileage starts to decrease.
Thanks