Running 25km in 35°C heat can make your muscles feel as sore as running 35km in cooler conditions due to several physiological factors, even though you might expect the primary strain to be on your cardiovascular system. Here's why:
Increased Metabolic Stress: In high temperatures, your body works harder to regulate core temperature through sweating and blood flow to the skin for heat dissipation. This diverts blood away from working muscles, reducing oxygen delivery and increasing reliance on anaerobic energy production. This leads to faster accumulation of metabolites like lactate, which can contribute to muscle fatigue and soreness.
Dehydration and Electrolyte Imbalance: Running in 35°C likely caused significant sweating, leading to dehydration and loss of electrolytes (sohim, potassium, etc.). Even mild dehydration (2-3% body weight loss) impairs muscle function, reduces endurance, and increases perceived effort. Electrolyte imbalances can also cause muscle cramps or micro-damage, amplifying soreness.
Higher Perceived Effort and Muscle Strain: While your pace may have been the same, the heat increases your rate of perceived exertion (RPE). Your muscles may have worked harder to maintain that pace due to reduced efficiency from heat stress. This can lead to more microtears in muscle fibers, similar to what you'd experience with a longer run in cooler conditions.
Glycogen Depletion: Heat increases carbohydrate metabolism as your body prioritizes energy for cooling and muscle function. Faster glycogen depletion can lead to earlier muscle fatigue, making your muscles feel as though they’ve endured a longer effort, like a 35km run.
Inflammation and Recovery: Heat stress triggers a greater inflammatory response post-exercise, which can exacerbate delayed onset muscle soreness (DOMS). The combination of heat and prolonged exercise may also impair recovery due to added strain on your body’s systems.
咁熱咁長時間, cardiac drift只會令你越來越辛苦, 再加上唔知你跑緊同跑完飲得夠唔夠水
