A Romulan with blood on his face. Nanoprobes assimilating blood cells. Blood is the circulatory fluid that runs through most corporeal lifeforms in the universe. Its primary function is to carry nutrients and respiratory gases to cells and to remove waste products.
Muscle is more metabolically active than fat, and building muscle can help increase your metabolism (36, 37, 38, 39). This means you will burn more calories each day, even at rest (40). Lifting weights will also help you retain muscle and combat the drop in metabolism that can occur during weight loss (41, 42, 43, 44).
Adrenalin levels are increased so that we have plenty of energy to go get more food. For example, 48 hours of fasting produces a 3.6% increase in metabolic rate, not the dreaded metabolic âshut-downâ. In response to a 4 day fast, resting energy expenditure increased up to 14%. Rather than slowing the metabolism, instead the body revvs it up.