What happens if heart rate response with exercise is blunted?
Cardiac output is the product of stroke volume and heart rate. It will not rise sufficiently with exercise if the heart rate does not rise adequately. Since the blood vessels in exercising muscles take up more blood, the flow to the brain will decrease if cardiac output does not increase. Hence the person is likely to faint.
A blunted heart rate response with exercise is called chronotropic incompetence. (chronos: related to time)