I do wonder about his reasoning though.... how bad is "lowered blood pressure" if you're doing something athletic which raises blood pressure?
As someone with low blood pressure, it's ghastly. When my blood pressure drops when I'm doing something athletic, my heart goes into overdrive. So I am now dizzy, faint, with a racing heart, probably sweaty as well. If I am somewhere safe, with people around, I will sit down or even lie flat, and hydrate with water, Powerade or black tea, depending on what is available, and maybe have some licorice. If I am working horses alone, I grit my teeth, grab onto the horse's mane, and have them tow me back to their field before I black out so I can strip their tack and then lie down to recover.
Basically, your systolic blood pressure
has to increase during exercise. The heart needs to get oxygen around your body, so it works harder. If blood pressure falls, the load on the heart increases. Exercise-induced hypotension is considered to be serious and an indicator of being at greater risk for cardiovascular events. And from my own experience, having blood pressure crashes when exercising is both counter-productive and dangerous.
That said, both systolic and diastolic blood pressure can increase dangerously during exercise for some individuals, so it does depend on the person, and probably on the exercise. As I am not an expert, I shall simply link to some articles on blood pressure and exercise, for those who are interested.
Systolic Blood Pressure Response During Exercise Stress Testing (2015 open access article in the
Journal of the American Heart Association)
What is a 'normal' blood pressure response during exercise testing? (Press release for 2018 journal article.)
Low but not high exercise systolic blood pressure is associated with long-term all-cause mortality (2021 open access article in
BMJ Open Sport & Exercise Medicine)
Peak Exercise SPB and future risk of cardiovascular disease and mortality (2022 open access article in
Journal of Hypertension)