Sommeil et exercice physique chez l'homme

Etudes comparées des rythmes circadiens et reflet actimétrique du sommeil de sportifs et de sédentaires en poste régulier de nuit

The aim of this study was to show the resistance and persistence of the circadian rhythm of temperature (T°) and the sleep quality of athletic subjects and sedentary subjects engaged in night work, and attempt to explain the mechanisms that influence these differences. The effects of night work on biological rhythms have been studied extensively in the past few years. The contradictory situations for the night workers irrefutably affect their biological systems. Individuals with high amplitudes in their circadian rhythms have been found to be more tolerant to shift work and this results in a greater stability of circadian rhythms. This seems beneficial in coping with frequent rhythm disturbances. The physical training program seems to improve several mechanisms of the human biological system: amplitudes of circadian rhythms were increased and the circadian rhythm period was more resistant to an environment extreme (night work, shift work, sleep deprivation, or jet lag). To test this hypothesis, athletes and sedentary subjects who were engaged in regular night work were selected in the PSA Peugeot Citroën Automobiles Group in French Normandy country. The circadian rhythm of the T° for both groups was studied with a specific methodology and with extensive spectral analysis, especially the spectral elliptic inverse method. Study models of the rhythm of the T° were determined and the characteristic parameters were exposed. A complementary actigraphic study showed the physical training program's effects on the sleep quality. The results revealed a large stability in the rhythm of circadian variation of T° for the athletes: the amplitude was still large but for the sedentary subjects the amplitude of the T° decreased and it was difficult to adjust a period on the rhythm of T°. The stability and persistent quality of the athletes' circadian rhythm was confirmed. We observed that the actigraphic sleep was greater for athletes than for sedentary subjects, and the acrophase time for the athletes was later than for the sedentary subjects during the night shift. Key words: circadian rhythm of temperature, actimetry, sleep quality, exercise, night work, methodology of rhythms analysis

Comparative effects of zopiclone and loprazolam on psychomotor and physical performance in active individuals

OBJECTIVE

Sedative hypnotics are used by athletes to alleviate precompetition anxiety and insomnia. The effects of these agents on exercise tolerance have not been extensively researched.

DESIGN

To determine the effects of sedative hypnotics on psychomotor and physical performance, a double-blind, placebo- (P) controlled, cross-over designed trial investigated the effects of zopiclone (Z) and loprazolam (L) on performance in 12 athletes.

INTERVENTION

Subjects ingested either P, Z (7.5 mg), or L (2 mg) on three different occasions separated by a 1-week washout period. Eye-hand coordination tests, a 30-m sprint test, an agility test, and a graded treadmill run to exhaustion for determination of VO2max were performed 10 hours after drug administration.

RESULTS

Subjects reported a significantly greater hangover effect following ingestion of L (8/11 subjects) compared with ingestion of Z (3/11 subjects; p < 0.01). A greater number of subjects felt alert after ingestion of P (9/11 subjects) and Z (9/11 subjects) compared with L (4/11 subjects; p < 0.01). The results of the eye-hand coordination tests, the 30-m sprint, the T-test, the VO2max, and the time to exhaustion during the treadmill run were not significantly altered following the ingestion of P, Z, and L. There was a significant difference between the delta values for Z and L for the number of missed responses in the eye-hand coordination tests (p < 0.02). Therefore, following the ingestion of L, subjects experienced a significant hangover effect and altered reaction time, whereas the ingestion of Z did not significantly impair either psychomotor or physical performance in the administered tests.

CLINICAL RELEVANCE

Investigate the extent of the effects of sedative hypnotics on exercise performances, enabling team physicians to prescribe such drugs to the athlete more effectively.

Influence of the composition of a meal taken after physical exercise on mood, vigilance, performance

The metabolic and behavioral effects of nutrients after exercise on vigilance level, performance, and mood have been minimally studied and have given contradictory results. In order to increase the understanding of the relationships between nutrition, exercise and performance, this experiment compared the effects on mood and performance of a protein- rich meal and a protein- poor meal, eaten just after an acute session of exercise. Vigilance and mood were evaluated by visual analog scales, and memory was measured by memory search task from the AGARD STRES battery, based on the Sternberg paradigm. Forty-two subjects were involved in this experiment. All subjects participated in the study of the effect of exercise after two kinds of meals (protein and nonprotein). Two groups of fourteen subjects we used to evaluate the effect of the exercise and the effect of the delay of meal intake after exercise in the two kinds of diet. The results show no difference in memory performance between exercise and rest conditions, nor between "protein" and "no protein" meal groups. They do show, however, that subjects feel happier after a meal with protein than after a meal without protein. The effects of the "no protein" meal on drowsiness differ with the glucide content of the meal. Subjects are less drowsy when they eat between 125 and 150 g of glucide than when they eat more than 150 g. The rousing effect induced by physical exercise is counterbalanced when subjects eat more than 150 g of carbohydrate. The anxiolytic effect of glucide is re-established.