Oh dear. When one hit the 50s, this is the most dangerous decade. All sort of diseases started manifesting. Last time, I see one of my friend in early 50s. He decided to retire. Within a year, he went into depression. Another friend, a lady suddenly developed breast cancer. And another lady friend, also cancer in the womb.
I think human age 50 to 60 is when our body and brain start it's transitional process to slow down. It becomes a manifestation on the consequences of the past 50 years of abuse and neglect.