Heart Rate No Longer Displayed

My heart rate used to be displayed at the bottom of my watch's screen. The sensors pickup my heart rate and can be viewed in the heart rate app. The watch also tracks my heart rate when I exercise. I can get other things to display on the screen's bottom, just not my heart rate. The watch did display my heart rate until the last update. I have shut down and restarted the watch a couple of times. Also changed what is being displayed at the bottom (compass, compass/elevation, and elevation) and each item is displayed with no problem, except my hear rate.