Running watches have developed so much over the last 20 years. Before GPS units that can track your location, and wrist-based heart rate monitors on which you can check your beats per minute at any point on a run, most runners – if they used a watch at all – had a stopwatch of some sorts, and that was it. Fast forward to today and you can get yourself a highend piece of tech that sits on your wrist and can do pretty much anything except make you a cup of tea.