[kazinator]

I'm deeply skeptical.

Sure, your blood pressure is not going to be low while you're doing aerobic exercise.

If you do a lot of aerobic exercise consistently, your heart will get bigger and stronger, with a lower resting rate. That will bring your pressure down. It's not uncommon for endurance athletes to feel unusually lightheaded when standing up because of the low blood pressure and slow heart rate.

[amarant]

One of my best friends likes his cardio. A lot.

Both his resting pulse and blood pressure are so low a nurse examining him (for what later turned out to be allergies) once thought he was dying and brought the hospitals cardiologist running while having someone else call the heart surgeon!

I'm honestly not sure his exercise regiment is even healthy, it's a bit on the extreme side, but I doubt tai-chi can bring down anyone's blood pressure as low as his!