Cardiorespiratory fitness: You don't need a lab to test it

https://medium.com/read-or-die....-hq/are-you-fit-enou
What is new?
Monitoring cardiorespiratory fitness (CRF), the most powerful driver of healthy longevity, has been out of reach for laypeople. In this post, I'm translating the latest science of estimating CRF into DIY methods for everyone.
Why it matters
CRF is entirely yours to either beef it up or bring it down. But without the ability to measure and monitor it, you fly blind with your exercise and lifestyle modifications.
What's next?
Readers can use and test drive validated methods of accurately estimating CRF to optimize their exercise and lifestyle routines.