What is not advised when basing exercise intensities?

Estimating maximum heart rate is not advised as a sole method for determining exercise intensities because it can lead to inaccuracies based on the generalized formulas often used, such as 220 minus age. This formula does not account for individual variability in heart rate responses, which can vary significantly from person to person. Also, a person's maximum heart rate can be influenced by various factors including genetics, training history, and overall health.

On the other hand, utilizing heart rate reserve is a more personalized approach that considers both maximum and resting heart rates, allowing for a more tailored intensity level suited to the individual's condition. Considering individual fitness levels is crucial as it helps to establish a baseline and make appropriate intensity adjustments that support progress without risk of injury. Monitoring recovery heart rate provides valuable insights into cardiovascular fitness and how effectively a person's heart can return to resting levels after exercise, which is essential for training adjustments.