Exercise for productivity research

Second- and fourth-grade students in Canada were more attentive and less fidgety in class after spending four minutes engaged in physical activity, according to a recent study by researchers at Queen's University. They found that engaging students in what they called FUNtervals improved students' attention and performance in school.
Gurd BJ, Le Mare L, and Ma JK. Classroom-based high-intensity interval activity improves off-task behaviour in primary school students. Applied Physiology, Nutrition, and Metabolism. 2014.
http://www.medicaldaily.com/fun-exercise-boost-kids-attention-school-performance-all-it-takes-4-minutes-308922