Recreational runners may try to exert themselves during their exercise, but Jessica Selinger, a neuromechanics researcher at Queen’s University in Kingston, has found that humans' natural tendency is to run at a speed that conserves calories. By studying data from thousands of wearable fitness trackers, the team found that regardless of distance travelled, runners tended to stay at a consistent speed that uses the least amount of energy. It seems the evolutionary drive to conserve energy is fighting our desire to burn calories while exercising. The research was published in Current Biology.