The same article noted:
‘It is never too late to start and every little helps, with any ten minutes of physical activity improving your health
My first thought was that if someone is healthy enough to do 12 hours of exercise per week then genetics and other issues beyond their control may be the reason they are not having heart attacks, strokes and afflicted with cancer. So it is the classic chicken and egg question.
This also does not speak towards the quality of life. Does it make you happy or are you simply addicted to exercise. I do appreciate that those two things do not have to be mutually exclusive but it can get to a point where people start to suffer stress fractures, become isolated and depressed, etc, etc.
Everyone has different abilities and limits. I did what in theory and according to the article would provide me ideal health and I have a compression fracture with arthritis and exercise caused bradycardia to show for that. Thus I hold studies showing either minimums or maximums with a great deal of skepticism as they relate to the individual. Too much can be as bad or even worse then not enough. It reminds me of a recent study that had to be halted because a number of participants started to literally die. If memory serves it was to show the great benefit of anti-oxidation supplements. The theory was grand but the supplements were literally killing people.
I have come to a point in my life where the questions I ask I am having fun and I am healthy and not slowly wearing my body down and setting the stage for chronic issues. I have been forced into the realization that I am now at an age when a small and minor inconvenience can quickly turn into something much more serious and potentially permanent. I still want to challenge myself, even push myself out of my comfort zone. To ride 100 K in a single ride, I will need to work up to at least 70 or 80 K. Likewise, to run a marathon, enjoy it and minimize the heart damage risks, one has to run a certain minimal amount. But there is still being able to be smart about it, finding the right amount to allow one to still have fun and the wisdom to actually listen to your body when it firmly states that it cannot run as fast or as far or ... just to meet some arbitrary, subjective and at the end of the day, meaningless objective. Objectives can be fun, add spice but there is no reason why they cannot be kept in their proper perspective.