I'm 43 and I haven't slowed down. I've been active since I was a kid.
I'm a very clean vegan--high carbs, tho veggies are also high protein (I get circa 150% of the protein RDA), and the more I cleaned up my diet, the less animal foods (esp. dairy), added oils, and junk food I ate, the better, more energetic, lighter I felt.
I never do straight Cathe in a week--I just want more variety. Flexibility has always been an integral part of my life, and I got into yoga along with running and weight-lifting in the late '70's.
I love creating my own Cathe Terminatrix routines, programming IMAX/Boot Camp intensity segments alternated with "lower" intensity step and kickboxing segments, that may run from 1-2 1/2 hours (depending on my time and energy levels). I do these on Saturday mornings. Then on Sunday mornings I do an extra long intense lower body resistance work, ala LG Extreme. I do BOSU, Slide, stairclimbing, elliptical, running, biking, hiking, jumping rope, in addition to power step and athletic drills. I do a wide variety of approaches to weight-lifting, mostly higher endurance anymore. As I reached my 40's, I decided that I didn't like the look of big muscles on me, and being naturally muscular, I'm trying to tone that down.
My running time is slower, but I was never a fast runner--and now I run at most once a week during nice months. That doesn't build speed, and I'm ok with that. I want more variety. I have a shoulder injury I'm dealing with, and that came from 2 decades plus of incorrect resistance exercises, that were standard when I started--so now I pay the price of years of incorrect mechanics with weight.
My body definitely holds onto the fat more than before I hit my mid '30's, but I'm a healthy weight. I eat cleaner and work out more than I did as a younger woman, and I'm in the most fit I've ever been, and I'm not as lean as when I was younger and didn't eat as good or work out as intensely or smart.
I've reached the point of being ok with this. I've thru with menopause, I look d*** good, esp. compared to most women my age, and I feel like a little kid--full of joy and energy. There's so many adventures I'm eager to try! I'm 43 years YOUNG!!