People who have done a lot of endurance training can have a resting heart rate of 50 beats per minutecompared to the normal resting heart rate of 70-80 beats per minute. This decreased heart rate in trainedindividuals is the partly result of:

A) endorphins released from the brain which have an inhibitory effect on heart rate.

B) parasympathetic activity becoming more active and sympathetic activity becoming less active at rest.

C) decreases in both sympathetic and parasympathetic activity.

D) sympathetic activity becoming more active and parasympathetic activity becoming less active at rest.

E) increases in both sympathetic and parasympathetic activity

Explanation:

The parasympathetic activity is responsible for the body's rest and digestion response when the body is relaxed, resting, or feeding, it basically undoes the work of sympathetic division after a stressful situation

The parasympathetic activity decreases respiration and heart rate and increases digestion

Increased sympathetic activity plays an important role in patho-physiological role in hypertension, particularly in the early stages which is evident by  increased heart rate and blood pressure variability

italy's population growth rate is almost at zero, the national statistics agency, istat, said on monday, mainly due to a dwindling birth rate.