in the 30-60 minutes before training to ensure that you’re properly hydrated before you start. Once you’re running, sip 150-200ml every 15 minutes. If you’re still thirsty afterwards, or failed to drink during the session, another 400-800ml may be required.—Joe

‘scared’, and not keeping track of your intake. Next time, drink only fluid-replacement drinks (about 600-750ml per hour) and not water. And practise drinking these amounts in your pre-race training runs. —Joe Beer, sports scientist and level-two triathlon

climes (or in hot working conditions in the UK) are still provided with salt tablets.For most runners, however, a sports drink should be adequate. I’d suggest 200ml of an isotonic drink just prior to running and 200ml every 15-20 minutes during your run