This paper examines the respiratory performances of sportspersons from the perspective of thermodynamics. Performing in a comfortable environment not only widens the respiratory smoothness of athletes but also boosts their performance. By psychometric analysis of the air-conditioned stadium environment, the type and quality of air conditioning can be forecasted. A new term, metabolic respiratory efficiency (MRE) is introduced in this paper which formulates the ratio of respiratory workdone to the energy supplied through glucose by metabolism. The effect of limited and excess metabolic oxygen supply on the MRE has been observed and in context of this, the percentage of glucose required for smooth breathing process with beforesaid air condition is also assessed. To enhance convenience, the ambient is dehumidified without overcooling the temperature in most indoor stadiums. A comparison of all these parameters is made for a number of sports to analyse the dependence of performance on variations of respiratory conditions and the type of air conditioning system required for indoor air-conditioned stadiums for respective sports.