Final answer:
The correct formula to estimate the peak heart rate is 'Peak HR = 220 - Age'. This calculation provides an approximate maximum heart rate, which tends to decrease as one grows older.
Step-by-step explanation:
The student has asked about the equation to calculate peak heart rate (HR). The correct equation among the provided options is 'Peak HR = 220 - Age'. This formula is used to estimate maximum heart rate (Max HR), which is the highest heart rate one can achieve during intense exercise. Maximum heart rates can usually range between 200-220 beats per minute (bpm), and they generally decrease with age. For example, a 40-year-old's Max HR would be about 180 bpm (220 - 40 = 180), and a 60-year-old's would be around 160 bpm (220 - 60 = 160).
It is important to note that while this formula provides a general estimate, individual Max HR can vary based on several factors, including a person's fitness level, genetics, and overall health. Additionally, the cardiac reserve reflects the difference between the resting and maximum cardiac output (CO), showing the heart's capacity to pump blood during physical activity.