A marathon runner experiences muscle cramping and a burning sensation near the end of the race. What explains why increased intensity leads to this localized muscular pain?

💡 Explanation

Intense exercise leads to anaerobic metabolism and lactate production. This results in lactic acid accumulation, which lowers the intracellular pH in muscle tissue, causing a burning sensation because sensory nerve endings are stimulated by the acidity; therefore, the pain arises due to pH change rather than glycogen, creatine or oxygen changes.

• Following vaccination, what immunological mechanism causes long-term protection against a specific pathogen upon re-exposure?
• Why does administering a loop diuretic to a patient with impaired renal function potentially lead to severe hypokalemia?
• If a patient exhibits alkalosis during surgery, which consequence related to blood oxygen transport is most likely?
• Why does GLP-1 receptor agonism promote weight loss in type 2 diabetics, differing from insulin's frequent association with weight gain?
• Following a vasectomy, why does a semen analysis sometimes show non-motile sperm in the initial weeks?
• Which risk increases as prior Streptococcus pyogenes infection causes rheumatic fever?