表題番号：2011B-282
日付：2012/04/04
研究課題競技パフォーマンスを向上させる生体リズム調節に関する研究
| 研究者所属（当時） | 資格 | 氏名 | |
|---|---|---|---|
| （代表者） | スポーツ科学学術院 | 教授 | 内田 直 |
- 研究成果概要
- 研究期間中の研究業績として2つの研究を行った。
１．Changes of the human core body temperature rhythm and sleep structure by 6-hour phase advance treatment under a natural light-dark cycle.
ABSTRACT
Objective
The extremities of core body temperature rhythm shifts and nocturnal sleep structure changes were examined during 6 days of 6-hour phase advance treatment using bright light and melatonin under the natural light-dark cycle.
Methods
6 healthy males received phase advance treatments with 1 hour bright light exposure after waking, oral melatonin (1.0 mg) administered in the early evening, and advancement of environmental routines intended to advance the onset of the sleep period 1 hour per day. Core body temperature was recorded continuously for 8 days comprising adaptation, baseline, and 6 treatment days. Nighttime sleep quality was evaluated by polysomnography (PSG) on adaptation, baseline, night 3, and night 6.
Results and Conclusion
The core body temperature nadir in each day compared with baseline advanced significantly (p < 0.05). The mean nadir had advanced approximately 4.5 hours from baseline by day 6. The only significant change found in sleep structure was REM sleep duration, which was significantly decreased in day 6 compared with baseline (p< 0.05). Significant negative correlations existed between nadir phase advances and %REM in baseline, day 3, and day 6 recordings. Thus, phase advances greater than 4 hours were possible under natural light-dark condition, although a phase shift of 1 hour per day may be too rapid to maintain normal sleep structure.
２．Circadian Variations in Muscle Strength, Dart Throwing, Wingate Test and Respiratory Measures at Rest During Ultra-short Sleep-wake Cycles
Abstract
We examined circadian variations in muscle strength, dart throwing accuracy, Wingate Test power expenditure, and respiratory performance at rest during a 2-4h ultra-short sleep-wake protocol. Eight healthy men participated in a 24h laboratory experiment involving 4 alternating cycles of 2h sleep and 4h wakefulness. Measurement of respiratory variables and performance tests (muscle strength, darts and Wingate Test) were conducted at the time of awakening and 2h after rising from bed, respectively. Circadian period phase reflected by body temperature rhythm was assessed by cosinor analysis of rectal temperatures measured throughout the experiment. Data were analyzed relative to time of day and circadian phases based on the time of each individual's body temperature minimum. Wingate Test performance and respiratory variables (・;VCO2, ・;VE and RER) demonstrated significant circadian variations. There were no significant variations in muscle strength or ・;VO2. Dart throwing accuracy was more directly related to subjective fatigue, with performance tending to decrease with increased degrees of fatigue. These results emphasize the usefulness of the ultra-short sleep wake-cycle protocol. To assess elaborate circadian variations in performance, especially measures of accuracy, chronobiological protocols such as the ultra-short sleep-wake cycle are required.