Muscle injuries and dehydration can also trigger cramps. Dehydration is the excessive loss of fluids in the body. Low levels of any of the following minerals that contribute to healthy muscle function may also cause muscle cramps: calcium.
The heart is a part of the cardiovascular system in fact its the main part so if you have heart disease another way of saying this is you have cardiovascular disease.
With vagus nerve innervation to organs inside of the thoracic cavity, damage to both branches of the vagus nerve will not cause a reduction in heart rate but an increase. There will also be an increase in blood pressure. This is because the vagus nerve provides parasympathetic support to the cardiovascular system.