Defining strenuous or vigorous exercise is largely a matter of perception, as it depends on how hard a particular activity feels to you. Someone who is out of shape may find a brisk walk quite strenuous while a marathon runner may not find it the least bit challenging. Your heart rate can tell you how strenuous your body considers an exercise to be. In general, the more strenuous the exercise, the faster your heart will beat.
Singles tennis, jump roping, running, jogging, race walking and aerobic dancing are a few examples of strenuous or vigorous exercise. Hiking uphill with a loaded backpack or bicycling at least 10 mph are also considered to be strenuous and may seem extremely strenuous if you are ordinarily sedentary. A hint that you are engaging in strenuous exercise is that you'll have to stop and breathe every few words during conversation.
Checking your heart rate during exercise can give you an honest reading of how hard your body is working. Start by finding your maximum heart rate, or MHR, which is the most exertion your heart is capable of. Subtracting your age from 220 is your MHR. A 30-year-old would subtract 30 from 220, leaving her with a maximum heart rate of 190. A 60-year-old has an MHR of 160. That means 160 is the maximum number of times your heart should beat per minute while you're exercising. Vigorous or strenuous exercise uses 70 to 85 percent of your maximum heart rate.
Drawbacks vs. Benefits
Very high intensity exercise increases the risk of injuries, can weaken the immune system temporarily while raising the risk of respiratory infection. However, vigorous workouts can also make you stronger, fight off obesity and offer a number of other important health benefits. Strenuous exercise can help fight depression and promote longevity in heart patients -- and reduce symptoms of asthma, osteoarthritis and type 2 diabetes.
Trying to do more than your body can handle can be dangerous, cautions University of Maryland Medical Center. Pain, shortness of breath or feeling you must cut your workout short can be signs that you are overexerting yourself. Take a step back and gradually increase exercise intensity as your body gains strength and stamina.