Scene One Breath Hold Training

I have a new app to test my heart rate. How about I fill up my bathtub and hold my breath underwater and see if my heart rate goes up,down or stops all together. I take a deep breath and slide into the warm water.

Oh no my app is broken, so I'm going to time how long I can hold my breath for. The water is so warm I feel like I could say under forever. What time did I get?