The American Heart Association recommends that a person should exercise to raise their heart rate to their target heart rate zone which is 50% to 85% of their maximum heart rate.
A chest strap heart rate monitor or a fitness tracker with built-in heart rate monitor enable you to maintain the optimum heart rate target zone for your specific goal. My website provides a lot of useful reviews about these devices so that you can choose a suitable one. best chest strap heart rate monitor