Fitness different every day?

Is it normal for you to feel quite different day to day during the same run? Some days I can run with a spring in my step for 30mins and others I have to drag myself along and stop a couple of times. Sometimes I can tie it down to how long since I ate food but not always.
I have been running for 6 months now and I thought it would get easier and easier. It has gotten easier I guess but it is still hard work. Is that normal?

[JainMD]

Hi,
I would say it is normal but what I am concerned about is whether you are consistent in running daily or do you take breaks for couple of days before you start running again.
There are several factors which could change everyday running like stress, anxiety, mood change etc.
But yes if you are consistent and you do hard work too then it will pay you in longer duration.
Hope this helps.
Bye.

[Pum]

I only run 3 or 4 times per week. Thanks.

[bit56]

The way you feel doing any sort of exercise can vary from day to day, just as JainMD stated. When I feel lousy, I just cut back on the intensity. I don't want to get hurt or sick, because my body is obviously telling me something. I'll walk or run slower, or opt for a shorter distance. If I'm in my aerobics class (which I teach), I may work at a lower impact. If I'm lifting weights, I'll do fewer reps. Don't push it if you're body's not up to it, but a little exercise is better than none at all.