“It’s an incomplete study, a work in progress,” said Simon J. Anthony, a virologist at Columbia University.

Exercise may protect against dementia in part by triggering an increase in the amount of irisin in the brain, says Ottavio Arancio, a professor of pathology and cell biology at Columbia University.

The common routine of sitting at work all day, then plopping down on the couch all evening horrify experts like Keith Diaz, an assistant professor of behavioral medicine at Columbia University.

The findings highlight “another example of the discrimination and inequities we see ... even in affluent societies,” said Mary Rosser, director of Integrated Women’s Health at NYP/Columbia.