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.
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.
Dizziness can be caused by a number of different reasons. I would HIGHLY recommend that you insist that your client see her physician before doing any further training. While it could be something fairly benign, it could also be something more serious. It’s ALWAYS better safe than sorry. If this were me with one of my clients, I would INSIST that she see her physician about this issue BEFORE she works out again (either with me as her trainer or alone).
My two cents.
I agree that she needs to see her doctor. I have had younger clients that would get dizzy or lightheaded from circuit training with 2-3 strength training exercises in a row, but in a younger person it is less alarming. The fact that it lasts a few hours is particularly noteworthy. Have her contact her doctor.