Sleep management and the performance of eight sailors in the Tour de France à la voile yacht race.

We observed how sailors manage their sleep and alertness before and during competition in a long-haul yacht race. Global performance of the teams was also recorded. We assessed eight sailors aged 21-30 years, split into four teams, who competed in the Tour de France à la Voile 2002 yacht race. Two phases of the race were examined: two legs in both the Atlantic Ocean and Mediterranean Sea. Sleep length, sleep debt, and sleepiness before competition and on board during the race were assessed using ambulatory polysomnography. Intermediate and final rankings were considered as a reflection of performance. A significant correlation was observed between the sleep debt before competition and the total sleep time on board during the Atlantic legs. The greater the sleep debt, the more sleepy the participants were. During the Mediterranean legs, almost all the sailors were deprived of sleep and slept during the daytime competitions. We observed that the final ranking in the race related to the sleep management strategy of the participants. In extreme competitive conditions, the effect of a good night's sleep before competition on performance is important. The strategy of the winners was to get sufficient sleep before each leg so as to be the most alert and efficient during the race.

Nutrient intake of elite sailors during a solitary long-distance offshore race.

The purpose of the present study was to determine the nutritional intake of 11 skippers during the four stages of a solitary long-distance offshore race. Body weight significantly decreased during the race (-1.31 +/- 0.32 kg, range 3.5 to 0.1 kg, p <.01). Total daily energy intake was 18.53 +/- 0.71 MJ x day-1 during the race, and it correlated negatively with the rate duration of each leg. Energy intake during the race was 19% greater than that determined for a subgroup of 5 sailors during a control period 2 months after the race. Nutrient intake expressed as percentage calories of total energy was estimated at 50%, 35%, and 15% for carbohydrate, fat, and protein, respectively. Voluntary fluid intake decreased with increasing race duration (p<.001). Despite high energy intakes, sailors lost body weight during the solitary offshore race. It was not possible to conclude that this change in body weight was related to fluid loss and/or a discrepancy between energy intake and energy expenditure.

Assessment of physical activity in daily life.

The absence of physical activity represents a major risk factor for coronary heart disease. Therefore, the evaluation of physical activity is a very current topic within the framework of epidemiologic studies. The aim of this study, based on the Baecke questionnaire, was to compare the various indices [leisure time activity index (LAI) and sport activity index (SAI)] obtained in a control population (control group) with those obtained in a population presenting risks of coronary disease [cardiovascular risk factor (CVRF)]. The control group consisted of 195 volunteers and the CVRF group of 69. All volunteers were between 27 and 60 years of age and had similar professional activities; therefore, the occupation activity index (OAI) evaluated in the original Baecke questionnaire was not taken into account. Maximal oxygen consumption (VO2max) was calculated for each volunteer using the indirect method involving shuttle run tests. The results have shown a direct correlation between SAI and VO2max in the control group (r = 0.309; p < 0.01), whereas VO2max did not appear to be correlated with the SAI in the CVRF group. This is probably because the VO2max value is underestimated. The use of indirect methods in populations presenting risk factors for coronary disease may be inappropriate, as the psychological attitude of the volunteers towards physical activity must be taken into account. Multiple regression analyses revealed that in both groups, 30% of the VO2max variations could be predicted by parallel variations in the mass of body fat and of the SAI, although the influence of these parameters is different in the two study groups.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of type and structure of complex carbohydrates response to physical exercise.

To examine the level of oxidation between different carbohydrate foodstuffs ingested one hour before exercise, three experiments were conducted in men. They performed a series of exercise tests of two hours duration at 60% VO2max preceded in experiment I by ingestion of one of five isocaloric (836 kJ) successive meals of bread, potatoes, rice, spaghetti, or glucose; in experiment II, by either spaghetti or glucose, both naturally 13C enriched; in experiment III, by one of four 13C labelled meals containing starches differing in their proportion of amylose and amylopectin and in their culinary preparation. Results show: 1) The following glucose and insulin response from the highest to the lowest was: glucose > potatoes > bread > rice > spaghetti and after 30 min of exercise a significantly lower blood glucose concentration observed after glucose and potato diets compared to the rice and spaghetti meals. The level of 13CO2 production from the food ingested in experiments II and III was expressed in terms of Atom Percent Excess (APE). Data suggests that spaghetti is oxidized to a lesser degree than glucose. The comparison between starches shows that gelatinized amylopectin is metabolized to the same extent as glucose when there is a progressive decline in the level of oxidation from gelantinized amylose and crude amylopectin to crude amylose.

Oxidation of corn starch, glucose, and fructose ingested before exercise.

The purpose of this study was to compare the metabolic and endocrine responses, and the amounts of exogenous carbohydrate oxidized, during prolonged moderate cycle ergometer exercise (120 min, 60% VO2max), preceded by ingestion of 13C enriched glucose (G), fructose (F), or pure corn starch (S) (1,592 kJ ingested with 400 ml of water, 60 min before the beginning of exercise) in six healthy young male subjects. Plasma glucose and insulin concentrations significantly increased in response to G and S feeding. The high plasma insulin values resulted in a significant transient reduction in plasma glucose concentration in the first hour of exercise and blunted the response of plasma free fatty acid and glycerol concentrations, when compared to the values observed with F ingestion, which did not modify plasma glucose or insulin concentrations. Over the 2 h exercise period, the percentages of exogenous G (67 +/- 9%) and S (73 +/- 8%) oxidized were not significantly different but were significantly higher than the percentage of exogenous F oxidized (54 +/- 6%). These results confirm that 1) exogenous F is less readily available for oxidation than G or S and 2) pure corn starch does not offer any advantage over glucose as a pre-exercise meal.