睡眠醫學二十六之心肺健康

今晚如常到體育館練拳，迎面而來的竟是身型龐大的振華(假名)，我自不然要椰榆一下這位運動場稀客! 偉民當然亦不甘示弱，表示知道勤做運動可以提昇心肺健康，奈何自己患有糖尿病，高血壓同睡眠窒息症(OSA)，所以不能太操勞，實在身不由己!

話說回來，睡眠窒息症如何影響心肺健康( cardiorespiratory fitness, CRF) 也是百家爭鳴，其實這是個十分重要的健康問題，低的CRF值常常與心血管疾病及死亡率扯上關係(1-2)。CRF值比其他常引用的心血管疾病風險指標(Cardiovascular risk factor) 更能預測死亡風險(mortality)及願境(prognosis)(3-4)，CRF值通常用metabolic equivalents (METS) 或 peak oxygen consumption (V′O2peak)作單位的。

最近有學者(5)透過系統評價(systemic review)及薈萃分析(meta-analysis)對此醫學難題作出研究，發現睡眠窒息症病人的V′O2peak值真的較常人差。不論年青(五十歲以下) 或年長(五十歲以上)的睡眠窒息症病人也是如此。奇怪的是較瘦的睡眠窒息症病人(BMI<30Kg.m-2)較肥的OSA病人有更低的CRF值! 低的心肺健康值( cardiorespiratory fitness, CRF)正好解釋為何睡眠窒息症病人會出現較弱的體能和不濟的生活質素(6-10)。同一組學者(11)亦發現OSA病人每天的平均運動量(mean number of steps per day of 5388 )遠遠低於醫學界倡議的運動量(每天行一萬步)。其實運動訓練就算在沒有改善病人BMI下，仍能大幅改善睡眠窒息的頻率(Apnea-hypopnoea index)，日間嗜睡(Sleepiness)及提昇V′O2peak值的。究竟睡眠窒息症如何影響病人的運動量(exercise capacity) 不得而知，可能是OSA病人平日的運動量不足因而引致低CRF值吧。因此將來可能要考慮將運動治療(follower-up physical exercise programmes)納入醫治睡眠窒息症的常規方案。

夜了，正想搭振華的順風車回家，不過他說要去附近的東菇亨吃夜宵。唉!真的沒他辦法! 好在陳X記已經搬走了，費事話佢知先!

參考文獻:

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