Short answers, pulled from the story.
Marcus Cicero wrote in 65 BCE that exercise alone supports the spirits and keeps the mind in vigor. This historical observation contrasts with modern statistics showing physical inactivity causes 9% of premature mortality worldwide.
A team led by Jerry Morris published findings in 1949 that established a direct link between physical exertion and heart disease. Morris observed that bus conductors suffered significantly fewer heart attacks than sedentary bus driver counterparts.
A runner's high involves the biosynthesis of anandamide, beta-endorphin, and phenethylamine. These three euphoriant neurochemicals flood the brain during continuous aerobic exercise to create a transient state of euphoria.
Moderate exercise has been associated with a 29% decreased incidence of upper respiratory tract infections. In contrast, prolonged high-intensity exertion increases infection risk by decreasing the concentration of lymphocytes.
The Ciclovía is a 70-mile stretch of road located in Bogotá, Colombia that shuts down each Sunday for bicyclists, runners, rollerbladers, and skateboarders. This event transforms the city's infrastructure into a communal gym for public physical activity.
Preliminary evidence from a 2012 review indicated that physical training for up to four months may increase sleep quality in adults over 40 years of age. A 2018 systematic review and meta-analysis further suggested that exercise can improve sleep quality in people with insomnia.