The fluids are blood and lymph. Blood is transported via arteries, veins and capillaries. Lymph moves through lymph vessels. Lymph eventually drains into veins, and is mixed with blood for recirculation. Adequate fluid intake is crucial to maintain blood health.
Cardiovascular fitness ensures good circulation.
The blood system is very sensitive to malnutrition. If microorganisms or unwanted substances penetrate the physical barrier, the blood and lymph system presents the second line of defense. Malnutrition lowers the bodies defense against invasive disease. The Hormonal and Nervous System 78 Blood also carries chemical messengers, called hormones , to tissue sites around the body. Hormones act as messengers to initiate a response to a change in conditions.