Implying that everyone is fit until they are old? Unfortunately, that just isn't true ...
My niece came to visit me here in Hebden Bridge in her mid-20s and a local walk had her redfaced, sitting on a bench with her head between her knees, and gasping for breath. What shocked me was that it wasn't a 10 mile walk over the big, steep hills which surround the town - it was a few hundred yards level walk to the shops. It took a serious pulmonary embolism to reduce me to that level of unfitness!
Some people are fit until their 80s, some are unfit in their 40s, therefore the thread is okay as it is.