When I run I often get a stitch. Why do they occur and can I make them go away without interrupting my run?
Ralph Perryman, Cambridge

Richard Watterston, physiotherapist, replies:
A stitch is caused when the blood flow to your internal organs is reduced and diverted to the working muscles. As your fitness improves you will become used to this, reducing the severity and number of stitches.

A simple method to control the onset of a stitch is to slowly increase the activity level and allow the blood flow more time to change. Start running slower than normal for the first third of your run, increasing to your normal speed for the remainder. If you encounter a hill drop your speed to ascend it.