Doctors: It's really important that you regularly exercise. Get your heart rate up high a few times a week with some sports! Doctors: Just 10,000 steps of walking every day is fine too! Doctors: Ok, how about 8,000 steps only once or twice a week. Can you do that? Doctors: For the love of god, please just get off the couch every once in a while...
Although the studies I glanced at say something like:
>2000 greatest reduction in risk
6,000–9,000 steps per day 50% reduced risk of CVD for 60+ year olds 10k steps, marketing for original pedometer
20k steps, best way to lose weight, almost nobody does this daily :)
Here is a depressing video High School Fitness (1962): https://www.youtube.com/watch?v=NGa6BPj3Mcw
And the easiest one to compare is of course US basic training standards that have gone down each time they have been revised since WWII.