My sister has very high blood pressure and cholesterol, both of which are increasing despite treatment with drugs. She is planning to take a holiday in the Gambia. Is this a good idea?

Dr Jules Eden replies: Yes, of course it is. To stay at home, afraid of becoming unwell on holiday, can only increase her anxieties. Perhaps a bit of relaxation on a west African beach may even help to reduce her blood pressure.

That's the good news, but before she does this I suggest she discusses with her GP the real risks of her condition. Blood pressure notoriously increases in the face of a doctor taking it; likewise she should get a good assessment of the state of her coronary arteries. This can now be done in five minutes by CT scan. If her vessels are fine and the BP is below 190/120, she should be OK. A good idea is to buy a home-monitoring BP kit. If she finds levels creeping up into the 200/140 area, she can bring them down quickly by taking nifedipine, but only under medical supervision.

My five-year-old son has been diagnosed with atopic asthma. We are planning to go to Canada later in the year. Is he safe to fly?

It is fine to fly with atopic or allergic asthma, brought on by certain allergens such as animal hair, pollens or the dreaded house-dust mite. These are not normally found in aeroplanes. When you arrive in Canada, he should be OK because there are completely different allergens there to which he has not become sensitised. But if you want to veer on to the safe side, always take his blue Ventolin inhaler with you.

· If you have any questions you want to ask Dr Jules Eden, email travel.doctor@theguardian.com, or write to The Flying Doctor, The Guardian, 119 Farringdon Road, London EC1R 3ER.