It has long been known that regular, moderate exercise is one of the best things you can do for your health, with studies showing that trained athletes have increased levels of natural killer cells that fight infection. But as anyone who practises endurance sports probably knows, hard training for an event like a cycle race or a marathon run can leave you with a dandy head cold or other upper respiratory tract infection (URTI).
人們很早以前就知道，定期而適度的鍛煉是對健康最有益的事情之一。研究表明，受過訓練的運動員體內抗感染的“自然殺傷細胞”水平升高。不過，練習耐力運動的人也許都知道，為參加自行車比賽或馬拉松長跑這樣的賽事而開展的艱苦訓練，可能會讓你患上頭傷風或其他上呼吸道感染(URTI)。
您已閱讀13%（565字），剩余87%（3909字）包含更多重要信息，訂閱以繼續探索完整內容，并享受更多專屬服務。