“What Is CrossFit?” Part 7: Heart Rate

 I think isn't a good idea to link heart and modernity. 
The heart have several millions years, it's the most important organ of the human body. I think we can't describe him with her react to the modern lifestyle (under 300 year for the car)..
Futher i think it's necessary to listen the heart to match with him, if your heart rate when you sit at your computer are the same that on a Cindy we have a disconnect between heart and reality.

Chuck is so well spoken and I could listen to him all day.  But, I think the question deserves a deeper exploration.  Heart rate can be a good measure of intensity during physical exertion even though it is susceptible to other factors that Chuck mentioned like caffeine, adrenaline, etc.  There is an ideal heart rate, or range, that allows for extended peak performance as opposed to failure.  And, that varies per person based on a variety of factors.  But, an awareness of that ideal training zone and seeking to improve upon it over time could certainly prove to be a great measurement tool.