I think I should start lifting weights more seriously- I know if I'm ever going to be a faster runner, I need some cross-training. When I was in the best shape of my life, I lifted weights 3x a week at the YMCA, and ran or did cardio on the in-between days. I'd see the same men every morning doing their routine, but I only ever saw 2 or 3 women in the weight room, period. For some reason, it's like all men just know how to lift weights- I'm fairly confident that my dad or brother could show me a thing or two, even though I can't remember actually ever being aware that they lifted weights. Now that I think about it, the reason I started lifting weights in the first place was because my husband bought me a book on weight lifting after I told him I wanted to lose some weight. I remember in college seeing weight machines for the first time and being so intimidated by them - I'd do my cardio stuff and hope that someone would hop onto one so I could see how to use it.
It's really a shame that women seem unaware of the benefits of lifting weights. Some women think they will get bigger by lifting, so they avoid it. Attention: unless you become a body-builder, you will just get leaner, not bigger. Also, lifting is the only way to change your metabolism (oh wait, I recommend breast-feeding for that also!).
Everyone knows that lean tissue burns more calories a day than fat, so adding lean tissue to your body is like doing a slow workout 24 hours a day. Despite popular belief, doing cardio does not increase muscle! Somewhere between 30 and 40, we all start losing muscle every year, so lifting weights becomes especially important then. And it's not just about staying thin, much of the slowness of movement/ declining balance that 'hits' with old age is due to all that muscle loss over time...so if you want to get around when you're old like you did when you were young, you know what to do.
I'm fairly confident that this is accurate information, but if you know it's not, please let me know!