When you're trying to lose weight through aerobic exercises such as running or weight training, the intensity of the exercise is reflected in how hard your heart is working. You can get a fairly accurate measure of the intensity of your exercise routine by checking your heart rate. Generally the higher your heart rate during physical activity, the higher the exercise intensity. By determining your maximum and target heart rates and then measuring your own, you can measure the effectiveness of your workout.
Maximum Heart Rate
Your maximum heart rate is the highest number of beats your heart contracts during a one-minute measurement. Use this number as a tool to measure training intensity. Measure your maximum heart rate while exercising to ensure you stay within a safe range and to measure if your workout is intense enough to raise your heart rate to acceptable levels. A formula is used to predict your maximum heart rate based on your age and gender. For women, the formula is 206 minus 88 percent of your age. For men, 220 minus your age. For example, if you're a 40-year-old woman, multiply 40 by 0.88 to get 35, and then subtract that from 206 to get a maximum heart rate of 171. This is the maximum number of times your heart should beat per minute during your exercise.
Target Heart Rate
Once you've determined your maximum heart rate, calculate your target heart rate zone, which indicates the level your heart can be exercised without being overworked. Exercising within your target zone will give you the best results for burning fat and losing weight. Working out above that zone will tire you out quickly, while working out below that zone will reduce your exercise intensity and effectiveness. The relative intensity of your workout will determine your target heart rate zone. For light exercise intensity, work at 40 to 50 percent of your maximum heart rate For moderate exercise intensity, work at 50 to 70 percent of your maximum heart rate. For vigorous exercise intensity, aim for 70 to 85 percent of your maximum heart rate. Using the example of a 40-yea-old woman with a maximum heart rate of 171, multiply 171 by 0.7 (70 percent) to get 120 to get the lower end of your target zone. Multiply 171 by 0.85 (85 percent) to get 145, the upper end of your target zone. This means your target heart rate for vigorous activity is 120 to 145 beats per minute.
Measuring Your Heart Rate
Determine your actual heart rate while exercising to see if you are within your target zone. Take your pulse on the inside of your wrist, on the thumb side, by lightly pressing the tips of your first two fingers over the blood vessels on your wrist. Count your pulse for 10 seconds, and then multiply by six to find your beats per minute. If your actual rate is above your target zone, slow down to avoid strain. If it is below, you might want to increase the intensity of your work out for maximum effectiveness.
If you're not currently in shape or just beginning an exercise program, start with light intensity exercises before gradually building up to a higher intensity. Your maximum heart rate is just a guide and should not replace a professional medical opinion. Your actual maximum heart rate might be as much as 15 to 20 beats per minute higher or lower. Discuss your target heart rate zone with an exercise physiologist or a personal trainer for a more definitive number. Ask your doctor if you need to use a lower target heart rate zone due to any medications you take or medical conditions you have. Several types of medications can lower your maximum heart rate and target heart rate zone.
Todd Maternowski began writing in 1996 as one of the co-founders of "The Chicago Criterion." He joined the local online news revolutionaries at Pegasus News in 2006, where he continues to work to this day. He studied religion at the University of Chicago.