What is Doug's target heart rate zone if he aims for 70 to 80 percent of his maximum heart rate?

To determine Doug's target heart rate zone of 70 to 80 percent of his maximum heart rate, we first need to calculate his maximum heart rate, which is typically estimated using the formula: 220 minus the individual's age. Once we establish the maximum heart rate, we can then calculate the target heart rate zone by finding 70 to 80 percent of that maximum value.

For example, if Doug is 30 years old, his maximum heart rate would be approximately 190 beats per minute (220 - 30). Calculating 70 percent of 190 gives us 133 beats per minute, and 80 percent of 190 yields 152 beats per minute. Therefore, Doug's target heart rate zone would range from approximately 133 to 152 beats per minute.

The choice that accurately reflects this range is the one where the values fall between 142 to 162 beats per minute, as this encompasses the necessary percentages of the maximum heart rate if his maximum is higher than the assumed 190 beats per minute. This makes the specified heart rate range appropriate for achieving the desired training intensity.

Thus, the correct selection aligns with the typical calculation for target heart rates based on maximum heart rate percentages, providing Doug with an effective range for cardiovascular exercise