A heart rate of 140 is considered by the American Heart Association to be within the target heart rate zone for people age 20 to 55 engaged in exercise. Raising your heart rate to a training level can help you to effectively burn calories and decrease your resting heart rate over time—giving you a lowered risk of cardiac-related disease. Exercises like running, biking and stepping can help you to keep your heart rate at 140.
Running is a simple form of cardio that you can do virtually anywhere with only supportive shoes and workout clothing. To keep your running intensity at a good training rate, the Aerobics and Fitness Association of America (AFAA) recommends checking your rate of perceived exertion. Check how hard you feel you are working when you run. If on a scale of one to ten, you feel that you are working at a 6, your heart rate is around your target range. If you need to raise your heart rate, simply increase your speed or run uphill.
You can check your biking intensity through perceived rate of exertion as well. According to Christ Carmichaels, training coach for Lance Armstrong, you can boost your intensity while you bike through interval work. Plan to bike hard for two minutes then lighter for two minutes, then decrease the time between intervals. You can also keep your heart rate up by biking on hills. If you cycle indoors during the winter, turn your bike resistance up for a harder workout or try an organized indoor cycling class.
Step training can keep your heart rate in its target range of 140 beats per minute, whether you take a class or use a step machine. If you use a step machine, use AFAA's rate of perceived exertion to make sure you are working hard enough. If you take an aerobics class, ask your instructor what you can do to keep your heart rate around 140. Most step classes are already formatted to bring your heart rate to an appropriate range, so any modifications you would need to make would be minimal.