My 47 year old wife just got a stress test back that said it was negative for Ischemia. She performed very well on the test, going 13 METS, 10 minutes on the treadmill with no pain and was able to reach 105% of her predicted max heart rate (I think it was 183). Blood pressure went to 184/72. However, the test also said that she had horizontal st depression in several of the leads (about 6 of them) at peak stress. The test report said that the st depression resolved by 2 minutes into recovery. The test also said her DUKE score was 3 (although I calculate it at 2.5, based on 10 minutes of exercise and 1.5 mm st depression). And the test report said that it was negative for ischemia with an intermediate chance of CAD and a 1% per year cardiac death rate predicted. I have found information about false positives, particularly in women and my wife is on 2 mg estradiol per day and has had a hysterectomy. Does any of this seem out of norm to you?
The test you described is normal.  During any exercise even in normal people the blood pressure has to do up, because a healthy heart has to pump blood to the exercising muscle, which is a normal requirement.  The St segment depression you described are secondary to tachycardia (increase in pulse rate), which normally occurs with exercise, so be rest assured.  The risk you mentioned is for any person of that age group Regards