This is a problem that you will recognize immediately. If after applying the mask for the first time you start to feel smothered, a sense of panic washing over you, your heart rate and breathing rate increasing, with an intense fear and need to escape, you are likely experiencing claustrophobia. If this occurs, you will benefit from a little extra help. It may be possible to find a mask that does not enclose your nose, such as nasal pillows. You may overcome the discomfort by practicing with the machine while doing something relaxing, like watching television. If it is simply unbearable, you may want to seek out alternative CPAP therapies.