Some organisms rely on aerobic respiration, where oxygen is used to produce energy. Anaerobic processes, on the other hand, are devoid of this characteristic element. Humans fall in the former category and require oxygen for a long-winded process known as oxidative phosphorylation, where biochemical energy from nutrients is converted to a much more usable form for the body. This procedure requires glucose to be broken down into pyruvate molecules, which are further dismantled to produce several energy molecules known as adenosine triphosphate (ATP). ATP molecules supply energy to the rest of the body and hence are known as the “molecular unit of currency for intracellular energy transfer.” Overall, oxygen molecules are only a modest constituent within this extensive process and involved at the very last stage known as the electron transport chain.

Aerobic cellular respiration is a finely tuned process of energy production that deviates drastically when an individual undergoes extreme physical exertion. When the demand for energy outgrows the body’s capacity for energy production, the human body reverts to an anaerobic form of cellular respiration. In this case, the process of breaking down pyruvate is forgone as they are instead transformed into a chemical known as lactic acid. Although this process is much less efficient, it facilitates the supply of energy at a much faster rate to continue a sustainable production of energy during periods of intense physical activity.

Lactic acid acts as a defense mechanism by disrupting or slowing down vital systems throughout the body involved in cellular respiration. This allows the lactate to create a burning sensation within the muscles, as well as release hydrogen ions into body tissues to increase the level of acidity and subsequently create a sensation of fatigue. Overall, these mechanisms prevent the body from permanent injury when it is physically exerted to extreme extents. Eventually, when the body does slow down, the lactate is converted back to pyruvate molecules and processed according to aerobic cellular respiration. Lactic acid functions to slow down the body and reach a recovery period where the body can regain homoeostasis and discard the lactate and other metabolites. In fact, the majority of lactic acid is cleared within 30 minutes to an hour. Contrary to popular belief, the lactic acid does not cause muscle soreness that results a day or two after a period of strenuous exercise. The soreness, also known as delayed onset muscle soreness, is related more to cellular damage within muscular tissue.

Exercise is an integral component of a healthy lifestyle. A buildup of lactic acid cannot be avoided but it can be controlled through several precautions during periods of strenuous activity. To begin with, it is important to stay hydrated. Recommendations dictate drinking 16-20 ounces of water a few hours before a workout and 7-10 ounces every 30 minutes during the activity. Also, it is important to maintain a consistent level of activity and to increase it gradually over time. By doing so, an individual can stay more physically fit and require less glucose for energy production while reciprocally increasing their lactate threshold. The level of lactate within a body during physical exertion can also be used as a unit of measurement for physical fitness.