I do not do HIIT training but I have athlete's heart. I run almost everyday 2 miles (more on the weekends). I am not a fast runner by any stretch of the imagina

I do not do HIIT training but I have athlete's heart. I run almost everyday 2 miles (more on the weekends). I am not a fast runner by any stretch of the imagination (I average around 10k/h while running). My heart rate varies from 40 to 32 depending on what I am doing and how relaxed I am (34/32 when I am going to bed and 40 while I am at the keyboard). With the above info taken into account, I have had several tests done to ensure my heart is okay. I had 24 hour heart monitor test, a ultrasound taken of my heart for several minutes and several ECGs. The cardiologist wasn't scared by them and gave me the okay. I, personally, haven't had any negative effects due to my heart rate being low.