Brenda Loube allows her staff to spend 30 minutes exercising during every working day. This may sound like a strange notion, but for many, it is routine.

Ms Loube is co-founder and president of US-based Corporate Fitness Works, which installs fitness facilities in organisations - and she walks the talk. She believes that staff are fitter and more productive when they spend half an hour doing exercise such as walking, cycling or going to the gym.