Which amino acid helps to spare bodily protein during endurance activities?

Glutamine is known for its role in protein metabolism and immune function. During endurance activities, the body can experience a significant breakdown of muscle proteins as it seeks to meet energy demands. Glutamine helps to "spare" bodily protein by participating in energy production and assisting in the maintenance of muscle tissue. It serves as a substrate for glucose production through gluconeogenesis, which can help reduce the need for the body to break down muscle protein for energy.

Additionally, glutamine plays a crucial role in maintaining nitrogen balance in the body. By providing nitrogen, it helps support the synthesis of other amino acids and contributes to the overall recovery process after endurance exercise. This function is particularly beneficial in preventing muscle wasting and optimizing recovery, making glutamine an important amino acid in the context of endurance activities.

Other amino acids, like serine, proline, and lysine, have different roles in the body and do not have the same established evidence for spurring protein saving during prolonged exercise as glutamine does.