Final answer:
Endorphins are naturally occurring peptides in the body that help regulate pain, often released during vigorous aerobic exercise leading to a sensation known as a "runner's high." These substances also play a part in balancing emotions such as anxiety and depression.
Step-by-step explanation:
Endorphins act as the body's natural pain regulators and are released in several areas of the body, particularly in response to stress or discomfort. During activities such as vigorous aerobic exercise, the body produces these endogenous opioid peptides, which can lead to a feeling often referred to as a "runner's high." This sensation is a combined effect of endorphins contributing to a state of well-being and euphoria while simultaneously reducing pain.
Interestingly, some research suggests that the runner's high may actually be due to the release of endocannabinoids rather than endorphins. Regardless of the specific substance involved, this response plays an important role in how the body handles stress and pain. Moreover, endorphins help regulate not only the pain but also have an effect on anxiety and depression. However, the body strives for balance (homeostasis); thus, with regular intense exercise, it may downregulate endorphin production during rest, which might cause an individual to seek more intense exercise to achieve the same feeling.
In terms of the biological and anatomical aspects, pain sensing nerves are concentrated in areas of bone that are metabolically active. These nerves are involved in sensing pain but also play a role in regulating blood supply and bone growth in these regions.