The study, published in the June issue of the Journal of Labor Research, shows that employees who exercise regularly earn approximately 9 percent more than those who do not.

FORBES: New Study Links Exercise To Higher Pay

"Manufacturers saw that it was cheaper to manufacture in Bangladesh and places like Cambodia than China, especially to those manufacturers in Europe, where transportation was cheaper than from China, " says Katie Quan, associate chair of the University of California, Berkeley, Center for Labor Research and Education.

WSJ: American Taste for Cheap Clothes Fed Bangladesh Boom

Undocumented workers in particular have long been considered "unorganizable, " according to Ruth Milkman, who heads UCLA's Institute for Research on Labor and Employment.

NPR: Labor Unions Now Recruiting Immigrant Workers