Brief Answer:
Cardiac check-up

Detailed Answer:
Greetings, madame! Thank you for your question and welcome to Health Care Magic. I carefully read your query.

I would recommend a cardiac check-up. Usually, coronary artery disease does not manifest with shortness of breath as presenting symptom, but there are also atypical cases which can do so. I come to understanding that, since this shortness of breath is worrisome to you, then it is a new thing and you did not have it priorly. Being a 53-year old woman and physically active simultaneously, does not consist a significant risk for coronary artery disease and my index of suspicion that this is what we are dealing with, is low. Since the chest X-ray found nothing wrong, hence the recommendation to search if there is something wrong with the heart, although, I repeat, my suspicion is low.

As about the heart racing, every time we perform physical activity or are under a lot of stress, heart beat goes up. As a matter of fact, there also is a formula for the maximal heart beat figures during exercise: 220-age. Therefore, in your case, heart beat is expected to be 167 beats per minute during exercise, and is considered normal as long as it is a regular one.

The check-up I recommended should include at least three tests:
1. EKG - to evaluate the heart electrical and conduction systems in resting state
2. Echocardiogram - to assess the heart structures - heart muscle and valves - in means of size, function and movement
3. Cardiac stress test - to assess any electrical sign, during exercise, which would be indicative of a blockage within a coronary artery. It is only if this test comes back positive, when it is highly recommended to perform a coronary angiogram.

I hope I was of help. Wish you a good health. I would be happy to help, if you have further questions. Please close the discussion and rate the answer, if you do not.

My best regards,
Dr. Meriton

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