How much energy does 1 mL of O2 provide?

The option indicating that 1 mL of O2 provides 20.1 J of energy is based on the understanding of energy release during aerobic metabolism. During aerobic respiration, a variety of substrates such as carbohydrates and fats undergo oxidation in the presence of oxygen to produce adenosine triphosphate (ATP), which serves as the primary energy currency of the cell.

In metabolic processes, it is well-established that oxygen is integral for the complete oxidation of nutrients. Each milliliter of O2 consumed corresponds to a specific amount of energy that can be derived from the accompanying oxidation reactions. Research indicates that the energy yield from 1 mL of O2 during these metabolic reactions approximates 20.1 J.

This value is widely accepted in the fields of exercise physiology and kinesiology when evaluating energy metabolism and the caloric expenditure during physical activity. It serves as a useful reference for estimating the energy costs of various exercise intensities and durations, aiding in assessing physical performance, training adaptations, and energy balance in different populations. Understanding this relationship between oxygen consumption and energy yield is fundamental in fields such as kinesiology, exercise science, and nutrition.