I have the same issue. This is why I feel like this for most of the day.

One thing to add, that haven’t been thought to me in the CPR course.

It’s fucking exhausting and you will get tired very soon. The training dummy doesn’t require nowhere near as much force as a real person. To give you an example, it’s quite common to crack or break a rib of the CPR recipient even if CPR is done right. That’s how much force you have to use. Without the required force, your pushes won’t reach the heart.

Make sure there is someone else who knows how to do CPR or at least is looking how you’re doing it and can repeat that or follow your commands once you switch.

I’ve only had to give someone CPR once and I haven’t been as tired in my whole life. No way the “I’ve been giving him CPR for 30 minutes…” You see on a TV screen is real. I felt like I’ll need CPR myself after 3 minutes.