Generally, a lower heart rate at rest implies more efficient heart function and better cardiovascular fitness. For example, a well-trained athlete might have a normal resting heart rate closer to 40 beats per minute. Vigorous activity feels challenging. Here are clues that your exercise intensity is at a vigorous level: https://messiahqyens.wikitelevisions.com/7727525/niet_bekend_factual_statements_about_bpm_calculator