exercise- how much can you push?

[JannaLee]

I went out for a short ski (cross country) on the lake and only got about a mile before I had to stumble back to my bed!  My joints are screaming and my face (45 spf sunscreen on) is stinging like the dickens!

2 years ago I could have gone 7 miles easily.

On top of that my balance is off now days and I almost killed myself climbing the bank back to the house!

Guess it's back to walking for me.  I truly hate this.