Among the more commonly cited reasons are the following:

Increases the degradation of oxyhemoglobin

Breaking down the chemical complex of oxygen and hemoglobin results in the release of oxygen from the blood, enhancing the delivery of oxygen to the exercising muscle.

Increases body temperature

The elevation in body temperature produced by warming up reduces the potential for skeletal muscle injuries and connective injuries, since cold muscle and tendons have been shown to be more susceptible to injury.

Increases blood flow to the exercising muscles

The greater level of blood reaching the muscles involved in the activity aids in the delivery of the fuels (e.g., glucose and free fatty acids) required for energy production.

Increases blood flow to the heart

A greater level of blood delivered to the heart reduces the potential for exercise-induced cardiac abnormalities (e.g., electrocardiographic disturbances), reducing the potential for myocardial ischemia.

Decreases the viscosity of the muscle

Reduced muscle viscosity increases the suppleness of the muscle, thereby enhancing the mechanical efficiency and power of the exercising muscles.

Causes an early onset of sweating

The earlier onset of sweating promotes evaporative heat loss and, as a result, decreases the amount of heat stored by the body. This will help to prevent an individual's body temperature from rising to dangerously high levels during (more strenuous) exercise.

Enhances the speed of transmission of nerve impulses

As nerve impulses are conducted at a faster rate, neuromuscular coordination tends to improve, resulting in better performance of certain motor tasks.

Increases the blood saturation of muscles and connective tissues

A higher level of blood reaching the muscles, tendons, and ligaments involved in the activity increases the elasticity of these tissues, resulting in a safer, more effective performance of stretching exercises.