How many runs should I do a week? I do about four at the moment and I wondered if that was too much.

I would never want to discourage anyone from exercising, especially if it is an activity they really enjoy. However, I would tend to suggest that anywhere between 1-3 runs a week is the most we should aim for – any more than this and you risk causing problems for the joints in the long run. The body also needs time to adapt and recover from vigorous activities and so sticking to this quantity of runs would allow for this.

Also, why not give your joints a bit of a break by incorporating some other activities into your week, such as cycling or swimming, which are not so high impact? We mustn't forget about strength work either, which is ideal for achieving optimum health. Yoga is a great option here as not only does it help to improve muscle strength, but it can also be a good way to ease out tension in the muscles after running on a previous day. I hope this helps, and that you enjoy getting some more variety into your exercise plan!