Heart rate from series 4 past 3 runs. Is the watch defective?

[MatthewUT44]

[doublepost=1546563235][/doublepost]Past 3 runs with my apple watch series 4. The straight lines are from the watches heart rate being grayed out. I was sweating during the run.

 

[chrfr]

View attachment 813933
[doublepost=1546563235][/doublepost]Past 3 runs with my apple watch series 4. The straight lines are from the watches heart rate being grayed out. I was sweating during the run.

Have you tried tightening up the watch on your wrist a bit?

 

[MatthewUT44]

Have you tried tightening up the watch on your wrist a bit?

It's already pretty tight with the small band. I can't make it any tighter I have tiny wrists

 

[chrfr]

It's already pretty tight with the small band. I can't make it any tighter I have tiny wrists

I have better luck with the sport loop when I’m doing activities, maybe that’d work better for you.

 

[sdwaltz]

As chrfr stated, it probably has to do with the watch band being too loose.