My husband has had a triple coronary bypass operation which has been successful, at least physically. But he has become obsessed with the feeling that he has a 'time bomb' inside his chest. Our doctor says this attitude itself could harm him and bring on another attack. Is this true?

Your doctor is right. Psychosomatic medicine experts report that if you have heart disease, the more open, outward-looking, curious and sociable you are, the longer you live. Dr Ted Kavanagh, of Chicago, trained his heart attack survivors to run marathons. They called him the Supercoach of the World's Sickest Track Club. Of course, not all people with heart disease can run, but they can all help their hearts by exercising them to their safe maximum. When they do, they feel a lot better physically and mentally. Your husband should seek advice on how to exercise appropriately, and on how to cultivate a better mental attitude to his past heart problems.

I've had a cat for 10 years with no ill effects. Now when he comes close, my eyes puff up and my mouth becomes so dry that my tongue sticks to the roof of it. Am I allergic to him?

It sounds like it. You can become allergic to a 'foreign' protein, such as cat saliva, even after being in contact with it for years. If you want to keep stroking him, you will have to take a daily antihistamine. Cats cover themselves in a thin film of saliva when they wash themselves and that's the cause of your allergy. It gets on your hands when you touch him; when you then touch your face, your eyes and throat react to it.

· Do you have a question for Dr Smith? Email doctordoctor@theguardian.com