Aerobic activity refers to exercise where oxygen is present in adequate amounts under normal conditions. This would include light exercise like walking, which does not include elevated breathing levels or heart rates. Anaerobic conditions conversely refer to exercise done where the level of exercise requires additional oxygen levels to sustain. Anaerobic exercise requires heavier breathing and elevated heart rates in order to sustain. The pushup exercise is one that varies in intensity between the type of pushup done and the number of repetitions completed in a set.
Pushups are an activity that works your arms, shoulders and chest muscles. The activity in its basic form consists of lying prone on the floor, putting your palms face-down on the ground, and pushing your body upward and away from the ground, using your feet to stabilize your lower body. Your body is raised until your arms are fully extended, then lowered until your elbows bend at 90 degrees. This constitutes one repetition of a pushup. Sets of anywhere between 10 and 100 pushups are common depending on individual fitness level.
Oxygen and Exercise
Muscles use oxygen to fuel metabolic activity to convert food nutrients into energy. This process is crucial to exercise because your body's muscles require more energy in order to contract at the rapid pace demanded by intensive exercise. Aerobic activity is activity where breathing alone supplies the oxygen required to sustain metabolic conversion. Anaerobic activity, however, describes conditions where the body cannot sustain the rate of conversion needed to continue contracting muscles. While no exercise is entirely aerobic or anaerobic, there is a metabolic threshold that describes the level of intensity that you can sustain while doing an exercise before fatiguing. When you fatigue, you are forced to lighten up or cease your exercise.
Why Pushups Are Anaerobic
Pushups can be a relatively light activity depending on your fitness level and the amount of reps you are doing in one set, without resting. However, pushups are not a sustainable exercise indefinitely. As you continue to push out additional repetitions, your muscles will begin to fatigue at some point. This alone indicates that pushups are an anaerobic exercise. However, the relative anaerobic level of the pushup exercise depends on your metabolic threshold, or the level at which you begin to fatigue while pushing up. At this point, your muscles switch from primarily aerobic operation to anaerobic operation.
Examples of Anaerobic Activity
Any exercise where you become fatigued or tired can be described as anaerobic. While any activity can potentially be anaerobic, exercises that can be sustained for long periods of time via low intensity are often referred to as aerobic and designed mostly to work the cardiovascular system. Common anaerobic exercises include weightlifting and sprinting, because your body is brought to its maximum metabolic threshold in order to boost peak performance and strength.