Final answer:
An adult's normal resting heart rate ranges from 60 to 100 beats per minute. Bradycardia is when the rate drops below 60 bpm, and tachycardia is above 100 bpm. Rates vary depending on various factors including fitness, age, and underlying health conditions.
Step-by-step explanation:
The normal resting heart rate (HR) for an adult is typically in the range of 60-100 beats per minute (bpm).
However, individuals may experience bradycardia, where the HR drops below 60 bpm, or tachycardia, where it exceeds 100 bpm. Factors such as fitness level, age, and specific health conditions can influence one's resting HR.
A resting HR lower than 50 bpm in symptomatic individuals can be cause for concern and might necessitate medical intervention, such as installing a pacemaker, especially if it is linked to cardiovascular diseases, metabolic disorders, neurological disorders, or other health issues.
Resting heart rates can vary even lower for highly trained athletes, sometimes reaching as low as 30-40 bpm.
It's important to note that a newborn's resting HR may be as high as 120 bpm, which gradually decreases into young adulthood and then slowly increases again with age.
In summary, the resting heart rates can deeply reflect an individual's overall health and physical condition.