When I got my bike computer(Wahoo Element Roam) I decided to get a Wahoo TICKR X heart rate monitor also. I never really used heart rate on rides. I just used my Apple watch to track my rides before. I am 44 years old. I noticed that I start to get fatigued when my heart rate gets up over 180bpm range. I know the info is good to have but I am not really sure if I am limiting myself with it. During my ride if I notice my heart rate climbing up near that 180bpm range I find myself slowing down a bit to try to keep it below that mark. At the end of my ride I will push myself and not worry about it really. I guess I need to research a better way to use the info. I am using it to pace myself so I don't burn myself out too early into a ride.
One thing I noticed with the heart rate monitor is the affects of caffeine before a ride. After work one day I was feeling a little sluggish. I decided to buy a energy drink and chug it before my ride. I don't know if me being tired was the bigger factor or the energy drink but I had a hard time keeping my heart rate in check. For almost the entire 15mile ride my heart rate was high. Hovering around the 180bpm mark. Now I just try to get hydrated and maybe eat a snack. No more energy drinks before rides lol.