Some people who suffer from asthma will be affected by altitude, whether in an airplane or simply at a higher elevation. If you are in relatively good health and your asthma is under control, however, you shouldn't have any serious problems with altitude, provided the ascent is not too fast. In some cases, asthma medication may need to be adjusted to cope with the altitude change.

If the conditions are very cold, inhalers may not work properly because the pressurization can be affected. If this is the case, warm them somehow prior to using them.

One of the reasons that higher altitudes can aggravate asthma is because the air is quite often drier and colder. If your asthma is often triggered by cold, higher altitudes could contribute to that.

If the higher altitude is reached by climbing - say hiking up a mountain - the exercise may also trigger asthma for some people. This is not exactly due to altitude, but this can add to the problem when combined with the changes in air and temperature at higher altitudes.

Some people may find that higher altitudes can actually improve their asthma. If a person's asthma is triggered by dust mites, altitude may help because dust mites are not able to survive in the colder temperatures.

If you are flying somewhere that is at a higher elevation, keep in mind that you won't have a chance to acclimatize yourself for the change. If this is the case, you should discuss it with your doctor to be sure you are prepared.