What calculation is used to determine the lower end of the Target Heart Rate Zone?

To determine the lower end of the Target Heart Rate Zone, the calculation involves using the maximum heart rate as a reference point. The formula typically starts with subtracting your age from 220 to find your estimated maximum heart rate. From there, the next step is to calculate 60% of that maximum heart rate to establish the lower threshold of the Target Heart Rate Zone, which is where moderate-intensity exercise typically begins.

By using the formula that involves subtracting the age from 220 and then multiplying the result by 0.60, this effectively provides the heart rate at which an individual should aim to maintain during exercise to reap health benefits, such as improved cardiovascular fitness without overexertion. This method is widely accepted in fitness training as a guideline for ensuring that individuals stay within a safe and effective heart rate range during workouts.

The other calculations presented either do not establish a range or focus only on maximum heart rate values, not targeting the necessary intensity levels for effective training. Thus, the approach that combines age, the maximum heart rate, and the appropriate percentage of intensity leads to the correct answer.