睡眠制約後代謝率提高下的異常血流動力學反應

我們進行這項研究的目的是要進一步瞭解是否睡眠制約，經由代謝率的變動，交感神經活性的升降，進而影響血流動力變化。於是設計在劑量差別的睡眠制約，即連續兩天，而每天僅能入睡三小時的安排下，量測之前之後的血流動力學變化。11位健康年輕人（5名女性）在正常睡眠(D0)或連續兩晚睡眠制約後(D1 & D2)，於次日早晨，於靜坐狀態下，接受非侵襲性氣體分析：例如通氣量（VE）、攝氧量(VO2)、二氧化碳排除量（VCO2）、攝氧通氣當量 (VE/VO2) 、二氧化碳通氣當量(VE/VCO2)與氧脈（O2 Pluse）；同時量測血壓（Blood Pressure）並藉由心電圖（Electrocardiography）計算心率變化。結果發現：相較於正常睡眠後，一天或兩天睡眠制約，明顯導致代謝率上升；而心率、舒張壓及平均血壓明顯下降，合併氧脈上升；而重力相關的肺部氣體交換結構－通氣當量（VE/VO2及VE/VCO2）亦明顯下降（與D0相較D1和D2有意義差別數據分別如下：攝氧量= 268±74相較312±65和309±71 mL/min，心率= 83±14相較77±9和78±12 beats/min，舒張壓= 68±9相較61±4和60±8 mmHg，平均血壓=83±10相較76±6和76±9 mmHg，氧脈＝3.4± 1.6相較 4.2±1.3和4.2±1.5 mL/beat，攝氧通氣當量= 44.8±12.7相較36.7±7.8和36.5±6.8，二氧化碳通氣當量= 45.5± 9.0相較41.3±6.1和40.9±5.5）。上述數值並未因一天或兩天睡眠制約而有所差別。因此面對因睡眠制約而上昇的基礎代謝率，卻結合反向心率及血壓的抑制。這種動力學的特異變化極有可能危害心血管系統。

To clarify the debate over whether sleep restriction (SR) affects hemodynamics via a sympathetic tone change in meeting a possible elevation of the metabolic rate, we conducted a dose response experiment before and after SR.We assessed heart rate, blood pressure (BP), and gas exchanges non-invasively at a resting, sitting upright position in 11 healthy young subjects (5 females) after a normal night sleep as well as after one- and two-day SRs.SR was defined as sleep duration reduced to 3 hours at dawn per night.In comparison with one night of normal sleep, the one or two nights of SR resulted in a decrease in heart rate (83±14 vs 77±9, and vs 78±12 beats/min; after normal sleep vs after one-day SR, and vs after two-days SR, both p < 0.05, respectively), reductions of diastolic (68±9 vs 61±4, and vs 60±8 mm Hg, both p < 0.005) and mean BP (83±10 vs 76±6, and vs 76±9 mm Hg, both p < 0.01) as well as a rise in oxygen pulse (3.4±1.6 vs 4.2±1.3, and vs 4.2±1.5 mL/beat, p < 0.005 and < 0.05) coupled with the simultaneous declination of ventilation equivalents for minute oxygen uptake (44.8±12.7 vs 36.7±7.8, and vs 36.5±6.8, both p < 0.01) and for minute carbon dioxide output (45.4±9.0 vs 41.3±6.1, and vs 40.9±5.5, p = 0.07 and < 0.05) while facing an elevated metabolic rate (268±74 vs 312±65, and vs 309±71 mL/min, both p < 0.05, respectively). However, no dosage effect was found between the one- and two-day SRs in all parameters. The results demonstrate that at a resting, sitting upright position, SR results sympathetic-related hemodynamics paradoxically at meeting an increase in metabolic demand, which may expose the cardiovascular system to risk.