infection. Your body is strong enough to fight and control it for the most part, but your immune system is compromised when stressed beyond the norm. Blood tests may shed some light. By the way, this month's Runner's World carries a warning from a doctor

, and partly for general health reasons. But I feel sluggish and my work is suffering. Is there really a point to this caffeine-free lark?" – Jane Hoskyn aka e17 pixieYour best answersResensitising really works, so brave it outI abstain from caffeine now

sorted before the day. I also made sure I did them on similar terrain as the event, practising nutrition and run-walk etc. Managed just under eight hours and 30th place, so not too slow. – Roger WaltersI'm a 45-year-old female runner who's run loads