Fitness Tracker for iPhone 5?

I have an iPhone 5 (not 5c or 5s) and I see the Health app, but even though I put steps on the dashboard ,nothing is happening when I walk. I tried to add a pedometer app from the App Store, but it says I don't have the M7 coprocessor so it won't work. Is there an app that will work if the phone doesn't have this coprocessor? Why does the phone have the Health app if it can't do anything?

Thanks!

Cheryl