Heart rate, like all: other body responses, controlled Mind↔Brain↔Body. Intrinsic (no nervous or endocrine signals from brain) heart rate typically ~100-120 BPM. When relaxed, parasympathetic orders from brain dominate resulting in slower & weaker heart contractions. With exercise, fear, anticipated need for possible action, etc. sympathetic orders ↑, parasympathetic ↓ & heart rate + strength of contraction ↑.
Answered 5/19/2016
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A doctor has provided 1 answer
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