blood pressure during exercise

Hi,

I am a 46 year old white male, live in Canada and have stage 1 hypertension which has been effectively treated with 2mg of trandolapril daily for about 9 years. I am an avid runner and generally a pretty active person - my blood pressure always drops during exercise to about 110 / 65 sometimes 105/60. I have a Vo2max of about 45 - 50 depending on conditioning and a max heart rate of 190 - 195 Could the trandolapril cause the hypotension during and after exercise or do you think there is a more serious underlying condition? From what I understand it would be normal for blood pressure to increase during exercise not drop?

Thanks,