Final answer:
Criteria for an adult to have a sustained heart rate of 120 bpm or greater includes being 18 years or older and having a resting heart rate that exceeds 120 bpm over a period. Normal resting heart rates for adults are between 60-100 bpm, and rates above this range may indicate tachycardia or other medical concerns.
Step-by-step explanation:
To establish criteria for an adult having a sustained heart rate (HR) of 120 beats per minute (bpm) or greater, it's important to understand what constitutes normal and abnormal heart rates. In adults, a normal resting heart rate falls between 60-100 bpm. Tachycardia is the condition characterized by a resting heart rate above 100 bpm, while bradycardia is when the resting rate drops below 60 bpm. Healthy young adults may experience an increase in heart rate to 150 bpm during exercise. Maximum heart rates can be estimated by subtracting the individual's age from 220. For example, a 40-year-old's estimated maximum heart rate is about 180 bpm, while a 60-year-old's estimated maximum would be around 160 bpm.
Considering the criteria to define a sustained heart rate of 120 bpm or greater in adults, the specific conditions would technically be: being aged 18 or older (1) and having a heart rate of 120 bpm or greater (2) that is sustained over time (3). However, it's important to note that while adults can have elevated heart rates, sustained heart rates significantly above normal resting levels may indicate a medical condition or response to physiological stressors and should be evaluated by a healthcare professional.