perfect one day out of breath the next

aidanki

first post in this forum, but long time lurker

anyway an observation I have on my own performance

I regularly run the 10k in less than an hour, I know nothing spectaluar, at least once a week sometimes more

however somedays by 2km I am panting and completely out of breath, and more days I am perfect

legs are never tired even after 1ok

regarding distance there are days after completing the 10k I could easily do another 5k

any ideas ? think its a bit strange is all

Slow_Runner

First off it sounds like your running these training runs way too fast, unless you're doing a specific speed session you should not be out of breath. Don't worry about it and just slow down - some days you will feel stronger and go faster and other days you will be tired and sluggish, just go with what your body is telling you.
Do you use a GPS watch to track pace? How often do you run, is it only once/twice a week? Consistency here is key, if you can regularly get out 2-3 times a week and run easy you will find you will be able to gradually increase your mileage and without knowing it your pace will increase with the same effort. Change around the distance as well, do 2 smaller runs and 1 longer one if you can, say 2 x 5-8k mid week and 10-15k on the weekend depending on how you feel.