In humans, acid-base balance helps to regulate the pH of body fluids. This is essential to ensure normal physiological activities. For example, pepsin— a protein-digesting enzyme present in the stomach, requires a highly acidic pH range of 1.5 to 2 for optimal activity. Any variation above this range can affect its rate of activity or may even inactivate it. HCl secreted by gastric glands helps to achieve the desired pH range in the stomach allowing pepsin to act on the ingested food. Contrary to stomach pH, normal blood plasma pH lies in the range of 7.35 to 7.45. Buffer systems, such as carbonic acid-bicarbonate buffer, phosphate buffer, and plasma protein buffer work in synergy to maintain this specific pH range. When blood pH falls below 7.35, the resulting physiological state is called acidosis. If the pH drops further below seven, it can affect the central nervous system and even induce coma in humans. In contrast, when the blood pH rises above 7.45, it causes alkalosis in the body and can lead to pain and cramps in the muscles.