How high is your heart beat supposed to go when you do low impact exercise?

I was diagnosed with HEDS Gonna get tested for Marfans in August of this year I know dysautonomia is a commorbidity with connective tissue disorders, however I was not diagnosed with that I have my suspicions though because my heart wants to go crazy sometimes at the slightest movement I can roll over in bed and my bpm is over 100 I can be sitting down eating and it will hit 145 Some days are better than others

But today I was following a low impact indoor walking workout on YouTube by Growwithjo, specifically this one: https://youtu.be/nmNCH-Ueq8E?feature=shared

And my bpm reached over 150, I hadn’t even hit a full 10 minutes in

Is this normal for a low intensity workout in the link?

I just want insight or advice/knowledge if anyone has it, I’m not looking for confirmation in diagnosis or anything online