I am a woman who has a family, full-time job, and a very busy life, generally.

Three years ago, I joined a local health club because I was not getting enough exercise. Since then, I have tried to work out three times a week. Every time I exercise on the treadmill, even though I am not running but only walking fast, I experience leg pain in the back of my calves. I have tried stretching to warm up but nothing seems to help. Do you have any suggestions? The pain in my calves is preventing me from increasing my speed and improving my conditioning. I would appreciate any suggestions you might have.

Can I run when I am pregnant?

I have recently started to stretch to start learning yoga and I have become sore in my muscles, and was wondering if I am sore the next day after stretching, is it okay to stretch the next day when I am still sore?

1) When I do a 3-mile or 5-mile run, I run for time and try to finish with nothing in the tank. The closer I get to the end, the more I push myself, because I know I don't need to sustain the effort much longer. When I stop running, I suddenly get very light-headed and dizzy. It never happens while I'm running. I walk briskly while I'm warming down, but that doesn't prevent it. Why does this happen? Is it dangerous?

2)  Sometimes after jogging a while, or cycling a great distance, my head begins to spin and I feel as if I'm going to pass out. Is it normal to have feelings like these, and if so, how intense should these feelings be?