From stopwatches and Channel hardy waterproof pocket watches to the Swim-o-Matic, a semi-automatic timer accurate to one-thousandth of a second: Elaine K Howley delves into the history of timekeeping in swimming. 

Every March, the United Kingdom and many other countries around the world, ‘spring’ forward one hour as longer days return to the northern hemisphere. While an hour might not seem like long enough to cause any real harm, this adjustment has been linked to a small but measurable increase in rates of heart attacks, strokes and traffic accidents.