RHR

RHR is an acronym with several meanings in different fields. The two most common are resting heart rate in medicine and the right-hand rule in physics and engineering. The term can also appear in other, less standardized forms depending on context.

Resting heart rate refers to the number of heartbeats per minute when a person is at rest, typically measured after waking and before activity. In adults, a normal resting heart rate generally ranges from about 60 to 100 beats per minute, though well-trained athletes may have lower values. Factors such as age, fitness level, medications, stress, illness, and temperature can influence RHR. Measurements are usually taken after a period of quiet rest, with the person seated or lying down. Clinically, persistently elevated resting heart rates may be associated with higher cardiovascular risk, while unusually low rates can indicate bradycardia in some individuals. RHR can be used alongside other metrics to assess fitness and autonomic balance.

The right-hand rule encompasses several related mnemonic devices used in physics and engineering to determine directions of vector quantities, especially in cross products and magnetic fields. A common version states that if the index finger points in the direction of the first vector and the middle finger in the direction of the second vector, the thumb then points along the resulting vector. A related rule, the right-handed grip rule, describes the direction of magnetic field lines around a current-carrying conductor. These rules help visualize orientation in electromagnetism and assist in solving problems involving torque, angular momentum, and field directions.

RHR also appears as an acronym in other contexts, varying by field and organization. When encountered, the intended meaning depends on the disciplinary setting and accompanying terminology.