Dear Madam/Sir There is preoccupation and anticipation for next sever attack which really frightening in Panic disorder. Since you are physically fit it is most likely tachycardia anticipated in dreaming. If your attacks are at least once a week better to take regular medication or SOS medication(Benzodiazepine) may do well. Some of the tips are-Go easy on yourself, Learn to identify your stressful triggers, become aware of negative thinking, learn to lower your level of everyday anxiety through a variety of techniques( meditation, yoga and exercise), learn other relaxation techniques( deep breathing or guided imagery), avoid stimulants, such as nicotine and caffeine, which can be found not only in coffee, but many teas, colas, and chocolate.