Proteins are macromolecules made up of amino acids. They are of vital importance to the human body as these macromolecules fulfil a wide range of functions.
Low temperatures are not necessarily a reason to stop outdoor exercises. Outdoor sport carried out at temperatures slightly below zero usually presents no problems - if you are properly prepared.
Sufficient protein intake is important for muscle growth. Only those who supply their muscles with enough can achieve their goals. There are several ways to additionally take protein.