You can connect this activity tracker to your iPhone and Android. You can easily keep track of your heart rate with its' built-in heart rate monitor.
From Amazon
HONOR Band 5 Fitness Bracelet, 0.95 Inch AMOLED Display, Tracker with Heart Rate Monitor, Heart Rate and SpO2 Monitoring, 2 Week Battery Life, 5 ATM, Pedometer, Midnight Navy
OnBuy
HONOR Band 5 Fitness Trackers HR, Activity Trackers Health Exercise Watch with SpO2 Heart Rate and Sleep Monitor, Smart Band Calorie Counter, Step C