Have you ever wished you could take a pill that mimics all the positive benefits of exercise without ever having to set foot on the Stairmaster?

Scientists at the Howard Hughes Medical Institute have identified two drugs that imitate many of the physiological effects of working out at the gymnasium, such as increasing the ability of cells to burn fat.

The drugs could offer protection against obesity and metabolic disorders, in addition to helping counter the effects of muscle-wasting diseases such as muscular dystrophy.

The drugs, which can be given orally, work by genetically reprogramming muscle fibres so they use energy more efficiently and can contract repeatedly without fatigue.

In laboratory experiments reported in the journal Cell, mice taking the drugs ran faster and longer than normal animals on treadmill tests. For instance, mice given AICAR, one of the two drugs, ran 44 per cent longer than untreated animals.

The second compound, GW1516, had a more dramatic impact on endurance, but only when combined with exercise.

As with exercise, the two drugs trigger a rise in levels of mitochondria, the structures in charge of producing energy; a shift in metabolism that takes advantage of lipids as an energy source; and an increase in blood flow, which allows the steady delivery of fat to burn.

你是否曾經盼望過，只要吞下一粒藥，你甚至不用踏上臺階機，就能取得酷似鍛煉帶來的所有積極效果？

霍華休斯醫學研究中心(Howard Hughes Medical Institute)發現了兩種藥物，可以模仿在健身房鍛煉后產生的許多生理反應，例如增強細胞燃燒脂肪的能力。

除了幫助抵御肌肉營養失調等肌萎縮疾病的影響外，這些藥物還能預防肥胖和新陳代謝紊亂。

這些藥物可以口服，它們的作用原理是對肌肉纖維進行基因重組，從而使肌肉纖維能更有效地使用能量，并能反復收縮，而不會產生疲勞。

根據《細胞》(Cell)雜志發表的實驗室實驗，在跑步機測試中，服用了藥物的老鼠比普通老鼠跑得更快、更持久。譬如，服用了AICAR（兩種藥物的一種）的老鼠，比未服用的老鼠跑動時間長44%。

第二種藥物GW1516對耐力的影響更神奇，但僅在與鍛煉結合時有效。

和鍛煉一樣，兩種藥物都會導致線粒體水平提高，新陳代謝發生改變，血液流通速度加快。其中，線粒體結構負責能量的生成，新陳代謝利用脂質作為能源，而血液流通則保證了供燃燒的脂肪的穩定輸送。