<Tr> <Td> Chemoreceptors </Td> <Td> Decreased levels of O; increased levels of H, CO, and lactic acid </Td> </Tr> <Tr> <Td> Baroreceptors </Td> <Td> Decreased rates of firing, indicating falling blood volume / pressure </Td> </Tr> <Tr> <Td> Limbic system </Td> <Td> Anticipation of physical exercise or strong emotions </Td> </Tr> <Tr> <Td> Catecholamines </Td> <Td> Increased epinephrine and norepinephrine </Td> </Tr>

What is considered to low of a heart rate