Originally Posted by
girljen
I have been bike commuting for about a month. My commute is only three miles each way; mostly downhill on the way to work and mostly uphill on the way home. The only riding I do right now is my commute. I usually work four days a week, sometimes five.
It will get easier over the first few months - could take 6 months before you think back to the beginning and realize that it's a lot easier than it used to be. Some of that is technique (i.e. doing the right things at the right times), and some of it is conditioning. Then after a few years you'll start to notice that it becomes harder - yep, we all get older!
Keep in mind that if you always do the same route you'll get used to that exact level of activity - adding more distance won't be easier, but at least you should adapt quicker to more cycling than if you were still green.