Possible causes:
- No breakfast
I've found that eating much in the morning on days when I'm running to work makes for an uncomfortable time. Toast or crumpets aren't too bad, just a bit gassy. Muesli is an absolute no no, I feel really slow and awkward afterwards. So lately I've been running to work with no breakfast. It should encourage my body to burn fat anyway. - Different, heavier shoes
I decided I needed to try the (only comparable) alternative to Vivobarefoot trail freaks, and bought a pair of Merrell Trail Glove 3s. They're a dead loss on muddy ground, the grip is terrible. But I can't afford to replace them straight away, so I'm currently flipping between my trail freaks and my old Inov8 roclites, which need 'using up' so I can get some lower heeled x talon 200s. Compared to barefoot shoes, the Inov8s are like diving boots. - Clothing
I'd made bad clothing choices. I had a fairly thick long sleeved base layer on (one of my old Regatta winter ones) and a Paramo windproof, and I was sweating buckets. So I took off the windproof, and was still too hot. I'd planned in the morning for strong winds, and they didn't appear. One of the difficulties with running both to and from work, coupled with the UK's ludicrously variable climate. - Mud
Ground conditions last night were pretty ropey, everywhere has been saturated by the recent heavy rain and it's like running through porridge. - The route
I don't know what it is about this route - maybe it's the rate of climb, or the pace I take it, but even at my absolute fittest I get to the top of the second hill completely boggered.
So in the end, distance in the morning was 10km/250m, and the evening was 16km/600m. Pace in the evening was shocking - 8:54 per km, fully 2 minutes per km slower than my target training pace. I gave up on the usual bonus hill reps as I was starting to bonk, and went home to eat something.
