Through consistent aerobic endurance training, the heart becomes stronger by the use of a progressive overload. Since the heart is stronger, it will force out more blood per each beat. Accordingly, the heart doesn’t have to exert itself as hard, and the individual’s heart rate at rest and in the course of exercise will be lower than it was before the individual began an aerobic endurance training programme. During exercise, the individual’s heart rate will be lower at a particular workload. For instance, let’s imagine that the individual’s heart rate taken instantly after running 800 metres on the initial day of training was 180 beats per minute (bpm). After 8 weeks of aerobic training, the individual’s heart rate ought to be considerably lower after running 800 metres at the matching pace that the individual ran on the first day of training. The precise amount is problematic to estimate because it varies from person to person.
An individual’s recovery heart rate will also progress due to the aerobic training. Using the aforementioned case, let’s say that it took 4 minutes for the individual’s heart rate to decrease from 180 bpm to 130 bpm after having run 800 metres on the first day of training. After 8 weeks of aerobic endurance training, the individual’s heart rate will decrease from 180 bpm to 130 bpm in much less than 3 minutes. Again, the enhancement in recovery heart rate will fluctuate from person to person. Despite this individual variability, it is safe to say that following a minimum of 8 weeks of aerobic endurance training, the individual can expect to see improvements in heart rate at rest (lower), and heart rate during recovery after a hard effort (less time to recover).
As we are focusing on heart rate related to fat loss, it is not necessary to go into too much detail with respect to the various training zones and their effects on the human body. But before that, it is important to know your Maximum Heart Rate in order for you to be sure that you are training at the right pace! You can easily find your Target Heart Rate by subtracting your age from 220 (which gives you your Maximum Heart Rate). What we are most concerned with is what is known as aerobic threshold training. This particular type of training is performed at intensities between the aerobic and anaerobic thresholds (anywhere from 60to 75 % of your maximum heart rate). These intensities are usually performed as long, slow duration (LSD) training sessions. Ultimately, aerobic threshold training is the minimum intensity that is recommended to improve aerobic fitness and reduce disease. Moreover, it is at the intensity we desire for maximum fat loss, where we can find up to 85% of calories expended are comprised of fat. This particular type of training can be performed for any length of time between 10 minutes to several hours (but this is highly unlikely to occur).