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).
Weightlifting is not the only way to speed up your basal metabolism. Your heart, which is made of cardiac muscle, can also be strengthened by aerobic activity, making it better able to pump blood through your body and burn calories throughout the day.