Measuring and recording heart rate data is essential to the HZE program. In fact, without accurate data, developing a training plan is not possible. Students may use a number of different assessments to develop their training plans, each of which is valuable in and of itself. When combined and compared with others, these assessments can show trends and starting points, which students can then use to make healthy exercise decisions. This is the power of a heart monitor: it helps students make health and fitness decisions.

Resting Heart Rate

Heart rate changes with the time of day, increasing during the daylight hours and decreasing during the night hours. Resting heart rate is the heart rate first thing in the morning, before getting out of bed. Because it measures parasympathetic nervous response, resting heart rate is one of the key indicators of overtraining or other stress.

Resting heart rate, sometimes referred to as a.m. heart rate, decreases as a result of positive training activities, meaning that as you get fitter, your heart works less to do the same work. A lower resting heart rate means less physiological stress on the heart muscle because it contracts fewer times. Although heart rate escalates dramatically during a training session, fitness training results in a lower resting heart rate, which translates to fewer contractions over the course of a lifetime. In other words, the heart of someone who exercises has to work less over that person’s lifetime. This is one of the training effect responses. The result of this training effect is that a person can save more than 700 million heartbeats over the course of a lifetime (learn more about this in appendix B). That’s quite a payoff in the long run.

Ambient Heart Rate

Ambient heart rate is frequently confused with resting heart rate. Ambient heart rate is measured when the person is awake but sedentary—for example, when resting in a sitting position while awake and involved in a sedentary activity such as working on a computer, watching television, or talking. Resting heart rate, on the other hand, is taken in bed before rising when the heart is at complete rest. Ambient heart rates change as a result of stimuli that influence heart rate including body position; external influences such as temperature, hydration, and food ingested; internal influences such as level of fatigue, stress, hunger, and sleep; and medication.

Ambient, or sitting, heart rate, like most heart measurements, is relative, not absolute. It is a number that needs to be compared to other ambient heart rate measurements. Taking ambient heart rates repeatedly gives a more accurate assessment than measuring it once. The normal range for ambient heart rate is usually between 50 and 90 bpm, but healthy ranges of ambient heart rates are very broad. The training effect is also seen in ambient heart rates. In other words, the fitter you become, the lower your ambient heart rate will be. Ambient heart rates under 60 bpm are rare. An ambient heart rate over 80 bpm may indicate a combination of various types of stress.