New to this site (and to running) but well done Gemini! - it's really different running outside after the treadmill and 20 minutes non-stop is brilliant. I only started in Feb.but managed the London Road Race (10k) in July and, like you am now signed up for the Nike 10k with a personal ambition to finish in under an hour...we'll see, I'm told Richmond has hills!!
I went out this morning too and managed my usual 10k route in 63 minutes-so I'm getting there. This was the woman who couldn't run for a bus 6 months ago!.
Alpen is yummy therefore must be healthy - I'm reliably informed that bananas are good too both pre and post run.