Quick Answer. In an officially-sanctioned MLB baseball game, there are 9 innings. If the home team is ahead in the top of the ninth and earns 3 outs, the game ends at 8 1/2 innings. If the game is tied after the away team earns 3 outs in the bottom of the ninth, the game goes into extra innings. Keep Learning.
When you exercise, the muscles you use require more energy. When exercise can be sustained, this demand is met primarily by aerobic means. Aerobic energy production in muscles results in increased gas exchange at the lungs, because more oxygen is taken in and more carbon dioxide is released.
The rate at which cellular respiration takes place (and hence oxygen is consumed) varies with the general state of activity of the body. Vigorous exercise may increase by 20 to 25 times the demands of the tissues for oxygen. This increased demand is met by increasing the rate and depth of breathing. The subject begins by breathing pure air (21% oxygen, 0.03% carbon dioxide, and about 79% inert gases by volume), first from the room and then from the tank.