personally, I would not try anything else until she has seen her doctor. TRX and body weight training is still just resistance in another form, and I would see no reason to assume that it will change the response in her body.
It is particularly troubling that it lasts for a few hours after her workout. I assume that she drives home in her car.
Harris lists a few possibilities, and there may be others but this needs to be checked.
Yes. There are a number of factors that possibly contribute to this, such as high blood pressure, diabetes, heart problems, poor diet, out of shape, etc. I would suggest to have a medical check up done by her doctor and see if it’s health related issue and eliminate some or all of the above guesses.