#Bangkokmarathon

A new wave of scientific insight has highlighted a dilemma familiar to every runner: when exhaustion sets in, is it your legs giving out first or your lungs and heart? The answer, experts say, could fundamentally alter the way athletes and casual joggers alike structure their training programs, and the latest research underscores the importance of accurately identifying the source of fatigue to improve running performance and overall health (Runner’s World).

A new wave of science helps untangle a familiar runner dilemma: when exhaustion hits, is it leg fatigue or cardiorespiratory fatigue? Experts say identifying the source can change how both serious athletes and casual joggers train for better performance and safer workouts. In Thailand, where running events and park runs are increasingly popular, this distinction is especially relevant for health, safety, and effective coaching.

Cardiorespiratory fatigue signals—breathlessness, a racing heart, and mental fog—often point to the cardiovascular system struggling to meet the oxygen needs of working muscles, even if the heart and lungs are not “weak.” The issue, researchers note, is how efficiently oxygen is delivered to and used by muscles. A leading exercise physiologist explains that mitochondria and tiny capillaries determine how well oxygen is utilized, not just how much is inhaled.