Anaerobic exercise

Lore & Background

Anaerobic exercise involves the biochemical process of glycolysis, where glucose is converted to adenosine triphosphate (ATP), the primary energy source for cellular reactions. The anaerobic energy systems include the alactic anaerobic system (using high energy phosphates like ATP and creatine phosphate) and the lactic anaerobic system (featuring anaerobic glycolysis). Fast twitch muscles operate using anaerobic metabolic systems, and any use of these fibers increases anaerobic energy expenditure. Intense exercise lasting upwards of four minutes may still have considerable anaerobic energy expenditure, as seen in high-intensity interval training performed at intensities exceeding 90% of maximum heart rate.

Reader's Guide

Anaerobic exercise is significant for its role in improving cardiovascular endurance, building and maintaining muscle strength, and aiding weight loss. It also increases an individual's basal metabolic rate (BMR). The by-product of anaerobic glycolysis, lactate, has traditionally been thought detrimental to muscle function, but this appears likely only when lactate levels are very high. Fatigue during intense exercise depends on multiple factors beyond lactate concentration, including energy availability, oxygen delivery, and psychological factors. Training can improve the effectiveness of anaerobic activity. Examples of anaerobic exercises include sprints, high-intensity interval training (HIIT), and strength training. In contrast to aerobic exercise, which includes lower intensity activities performed for longer periods, anaerobic exercise is more intense but shorter in duration.

Did You Know?

• Anaerobic exercise breaks down glucose without using oxygen, meaning 'without oxygen'.
• The alactic anaerobic system uses high energy phosphates like ATP and creatine phosphate.
• Anaerobic glycolysis exclusively uses glucose and glycogen as fuel in the absence of oxygen.
• Elevated muscle and blood lactate concentrations are a natural consequence of high-intensity exercise that exceeds the lactate threshold, not of any physical exertion.