Researchers at the University of Kent in the UK asked two groups of volunteers to play puzzle games and watch a documentary about sports cars, and then gave them an indoor bicycle endurance test. As a result, members of the first group who felt exhausted were more likely to give up than the second group However, the researchers found no differences in blood pressure, oxygen consumption, and cardiac output in the two groups of volunteers. From this we can infer:. ['Brain activity affects physical strength is just a sensory bias.', 'Physical fitness is very similar between the two groups of volunteers.', 'Playing puzzle games consumes the same amount of energy as watching TV.', 'Physical work can stimulate the potential of mental workers.']