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We evaluated the effects of the fluid replacement strategy on core temperature, heart rate and urine osmolality during a 27-km trail run in tropical climate. 20 well-trained runners completed a 27-km trail race in tropical conditions. They were acclimatized to these conditions. Heart rate was monitored every 5 s, while core temperature and perceived thermal and comfort sensations were recorded before, at the 11(th) km, and just after the end of the race. Water intake, urine osmolality and body mass were measured before and after the race. Core temperature and the scores of perceived thermal and comfort sensations were significantly higher at the 11(th) km and at the end of the race compared to before the race, but not at the 11(th) km compared to the end of the race [corrected]. No participant exhibited dehydration as assessed by urine osmolality. The less the trail runners weighed, the greater the heat retention was. The less hot they felt at the end of the race, the more they lost water, and the better the performance was. The fastest runners were able to tolerate a greater variation in core temperature between the beginning and the end of the trail race with lower water intake.

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The tropical climate is unique in that the seasons are dominated by the movement of the tropical rain belt, resulting in dry and wet seasons rather than the four-seasonal pattern of changes in temperature and day length seen in other parts of the world. Humid tropics are characterized by consistently high monthly temperatures, often exceeding 18 degrees C throughout the year; and rainfall that exceeds evapotranspiration for at least 270 days per year Although considerable information has been gathered on the physiological adaptation to hot/dry climates, data on acclimation to hot/humid climates are still limited. This review focusses on the effects of the tropical environment on human exercise performance through studies performed in the Caribbean, with a special emphasis on prolonged aerobic exercise such as swimming, cycling and running.

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The tropical climate is unique in that the seasons are dominated by the movement of the tropical rain belt, resulting in dry and wet seasons rather than the four-seasonal pattern of changes in temperature and day length seen in other parts of the world. Humid tropics are characterized by consistently high monthly temperatures, often exceeding 18°C throughout the year, and rainfall that exceeds evapotranspiration for at least 270 days per year. Although considerable information has been gathered on the physiological adaptation to hot/dry climates, data on acclimation to hot/humid climates are still limited. This review focusses on the effects of the tropical environment on human exercise performance through studies performed in the Caribbean, with a special emphasis on prolonged aerobic exercise such as swimming, cycling and running.

El clima tropical es único en el sentido de que las estaciones están dominadas por el movimiento del cinturón de lluvias tropicales, que trae como consecuencias estaciones de seca y lluvia, antes que el patrón de cuatro estaciones que produce los cambios de temperatura y duración del día, observados en otras partes del mundo. Los trópicos húmedos se caracterizan por temperaturas mensuales consistentemente altas, que a menudo exceden 18°C a lo largo del año, y precipitaciones que exceden la evapotranspiración durante por lo menos 270 días en el año. Aunque se ha reunido considerable información sobre la adaptación fisiológica a los climas cálidos y secos, los datos sobre la aclimatación a los climas calientes y húmedos, son todavía limitados. Esta revisión se centra en los efectos del ambiente tropical sobre el rendimiento de los ejercicios humanos a través de estudios realizados en el Caribe, con un énfasis especial en ejercicios aeróbicos prolongados, tales como la natación, el ciclismo, y la carrera.

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The Tropical climate imposes a high level of physiological stress, which could modify the target heart rate in training load prescription, as the recommendations are often determined by maximal oxygen uptake testing in temperature-neutral laboratories. To test this hypothesis, 7 high-level cyclists performed two randomised maximal tests in neutral (19.2±0.9°C; 51.7±1.3% RH) and Tropical environment (25.8±1.1°C; 63.7±2.3% RH). Neither maximal oxygen uptake nor ventilatory threshold was influenced by the environmental conditions. However, ventilation (p<0.005) and the respiratory equivalent in O(2) (p<0.05) were significantly higher in the Tropical environment, whereas maximal power output and the time to attain maximal oxygen uptake were significantly lower (p<0.05 for both). Moreover, the ventilatory cost of cycling (expressed in LW(-1)) was significantly greater in the Tropical condition (0.40±0.03LW(-1) vs. 0.32±0.05LW(-1), in Tropical vs. Neutral; condition effect: p<0.005; condition × time: p<0.001). Rectal temperature was influenced by neither the environmental conditions nor exercise (36.7±0.1 and 37.0±0.1°C vs. 36.8±0.1 and 37.1±0.2°C, in Tropical vs. Neutral, before and after exercise) but was influenced by condition × time (p<0.05). The heart rate (HR) values usually used for training prescription were not significantly different (154±5bpm vs. 156±4bpm and 172±4bpm vs. 167±4bpm in Tropical vs. Neutral climate, for the first and second thresholds, respectively). We concluded that the usual parameters measured during maximal exercise to establish training programs are not impaired in moderate Tropical environment. Nevertheless, the thermal stress attested by the increased ventilatory cost of cycling could have prevented the cyclists from performing a true maximal test in Tropical conditions.

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OBJECTIVE: Obesity is the source of many health problems in Guadeloupe. The aim of this study was to describe the relationships between daily energy intake and expenditure, and weight status. METHODS: Three consecutive daily recalls for activities and food intake were used to assess energy expenditure and energy intake in 20to 60year old Guadeloupian men and women. RESULTS: The absolute daily energy expenditure was correlated to the body weight (r = 0.64, p > 0.001) and to the daily energy intake with more strength in the normalweight group (r = 0.52, p < 0.001) than in the overweight group (r = 0.26, p < 0.05). in both weight groups, the higher the metabolism was, the larger was the difference between energy intake and energy expenditure. CONCLUSION: Under-reporting was probably present in overweight women. However, higher energy intake and expenditure were observed in larger persons who were consequently not identified as less active.

OBJETIVO: La obesidad es fuente de muchos problemas de salud en Guadalupe. El objetivo de este estudio fue describir las relaciones entre la ingesta energética y el gasto de energía diarios, y el estado del peso. MÉTODOS: Tres reportes consecutivos diarios sobre las actividades y la ingesta de alimentos, fueron usados para evaluar el gasto de energía y el consumo de energía fueron usados el consume de alimentos fueron usados para evaluar el gasto de energía y la ingesta energética en hombres y mujeres guadalupanos de 20 a 60 años de edad. RESULTADOS: El valor absoluto del gasto diario de energía fue correlacionado con el del peso del cuerpo (r = 0.64, p > 0.001) y la ingesta diaria de energía con más fuerza en el grupo de peso normal (r = 0.52, p < 0.001 que en el grupo de sobrepeso (r = 0.26, p < 0.05). en ambos grupos, mientras más alto era el metabolismo, mayor era la diferencia entre la ingesta y el consumo de energía. CONCLUSIÓN: En el caso de las mujeres obesas, probablemente los reportes quedaron por debajo de la realidad. Sin embargo, se observaron ingesta y gasto de energía más altos en personas más corpulentas, que por consiguiente no fueron identificadas como menos activas.

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The status of ethnic minority has been reported to be associated with a tendency toward sedentary behavior. The Guadeloupean population is composed of Afro-Caribbeans and an Asian Indian minority. This study examined the association of ethnicity and physical activity on the island. Energy expenditures (EE), energy intakes (EI), and macronutrient intakes of 122 Guadeloupean workers (60 Indians and 62 controls) were assessed by three consecutive 24-h recalls. Two-way analyses of variance were conducted to test the hypothesis of an effect of ethnicity, taking the potential effect of sex into account, on these variables. Asian Indians reported lower EE (P=0.011), lower EE/EI ratios (P=0.001), and lower physical activity (P=0.003) than their Afro-Carribean counterparts. Their food intakes were not different in terms of EI or macronutrient intake. No sex x ethnicity interactions were significant. The present study reports a tendency toward physical inactivity in Asian Indians of Guadeloupe associated with EI similar to those of controls. Sedentary lifestyles and energetic imbalances are well-documented risk factors for several diseases, including type 2 diabetes and cardiovascular disease, both major public health concerns in Guadeloupe. Strategies to prevent sedentary lifestyles should be considered for Asian Indian Guadeloupeans.

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OBJECTIVE: Obesity is the source of many health problems in Guadeloupe. The aim of this study was to describe the relationships between daily energy intake and expenditure, and weight status. METHODS: Three consecutive daily recalls for activities and food intake were used to assess energy expenditure and energy intake in 20- to 60-year-old Guadeloupian men and women. RESULTS: The absolute daily energy expenditure was correlated to the body weight (r = 0.64, p > 0.001) and to the daily energy intake with more strength in the normal-weight group (r = 0.52, p < 0.001) than in the overweight group (r = 0.26, p < 0.05). In both weight groups, the higher the metabolism was, the larger was the difference between energy intake and energy expenditure. CONCLUSION: Under-reporting was probably present in overweight women. However, higher energy intake and expenditure were observed in larger persons who were consequently not identified as less active.

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This study investigated 1) whether ventilatory and lactic thresholds (VT and LT, respectively) are different in sickle cell trait carriers (SCTc) and subjects with normal hemoglobin (control group), and 2) whether the first LT and VT and the second LT and VT are respectively coincident in the two populations. Seven SCTc and 8 control subjects performed an incremental exercise test (IET). Blood lactate concentration and cardioventilatory variables were analyzed at rest and during IET. No significant difference in the ventilatory parameters (notably, maximal oxygen uptake [VO (2max)] and the ventilatory thresholds) or the lactic thresholds was observed between the two groups. In both SCTc and control subjects, the LTs and VTs did not occur at the same exercise intensity. The first VT did not coincide with the first LT, in contrast with the second VT and the second LT, which coincided in both groups. In conclusion, SCTc exhibited normal ventilatory and lactic responses during a progressive and maximal exercise test assessing aerobic physical fitness.

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Sickle cell trait (SCT) is a genetic abnormality affecting the synthesis of normal haemoglobin [Hb] and is the heterozygous form of sickle cell anaemia. The aim of the present study was to compare the ability to repeat maximal cycling sprints (RSA; repeated sprint ability) between SCT carriers (SCT group, n = 7) and a control group with normal haemoglobin [Hb] (n = 7). The two groups performed a 10-s maximal cycling sprint in order to determine the peak power output (P(peak10)). They then performed an RSA test that consisted of five 6-s maximal cycling sprints interspersed with 24 s of passive recovery. For each sprint, the peak power output (P(peak6)) and the work over the 6-s (W6) were calculated. The sum of each W6 developed during the test was considered to be the total work (W(tot)). The decrements over the repeated sprints for P(peak6) (P(6dec)) and W6 (W(6dec)) were also determined. We found no difference in P(peak10), W(tot) and W(6dec) between the two groups. However, the drop in P(peak6) and W6 during the RSA test appeared earlier in the SCT group and the decrease in P(peak6) over the RSA test was greater in the SCT group than in the control group (p < 0.05). In conclusion, we found that: 1) maximal anaerobic performance determined during a single sprint was not altered by SCT, but 2) repeated sprint ability was different in SCT carriers compared with sportsmen with normal Hb.

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To characterise the anthropometrical and physiological parameters of French West Indian monofin swimmers, seven French West Indian male competitors underwent anthropometrical measurements and physiological testing. The results were analysed in relation with their performances during national and international events (from 50- to 1500-m). We found that both anthropometrical and physiological (aerobic and anaerobic components) factors contributed to the performances of these swimmers. The results demonstrated that certain parameters consistently contributed to the global performance: aerobic parameters (maximal oxygen uptake and the second ventilatory threshold, R (2) = 0.72 and 0.69, respectively), anaerobic parameters (power obtained with the counter-movement jump [R (2) = 0.58] and the force-velocity test [R (2) = 0.54]), leg volume (V1, R (2) = 0.54) and perimeter (P1, R (2) = 0.64), and fat and lean body mass (R (2) = 0.76 and 0.62, respectively). Further studies are needed to compare these determinants of performance in French West Indian and European swimmers and to investigate how they contribute to swimming technique.

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Whether or not whole blood lactate concentration is the same during a ramp exercise test in subjects with sickle cell trait (AS) as in normal subjects remains a point of controversy in the literature. Some studies have shown that the ability to produce or clear circulating lactate might differ between AS and subjects with normal haemoglobin (AA). If this is indeed so, the lactate distribution in the blood compartments should also differ. To test this hypothesis, lactate concentrations in the whole blood, plasma and red blood cells of AS and AA were compared at rest and in response to exercise. Eight AS and 8 AA performed an incremental exercise test. Whole blood, plasma and red blood cell lactate concentrations, the red blood cell : plasma lactate concentration ratio, the plasma-to-red blood cell lactate gradient, haematocrit and cardiorespiratory variables were analysed at rest and during an incremental exercise test and active recovery. Maximal oxygen uptake and ventilatory thresholds were similar in the two groups. No significant difference in whole blood, plasma or red blood cell lactate concentrations was observed between the two groups at rest, during exercise, or during the immediate recovery. Neither the red blood cell : plasma lactate concentration ratio nor the plasma-to-red blood cell lactate gradient differed between groups. Lactate distribution in the blood compartments did not differ between the two groups and this finding suggests that lactate production and/or clearance is quite similar during exercise in AS and AA.

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Seven acclimated elite road cyclists were recruited from among the participants in the Tour de Guadeloupe, a 9-day cycle race (D1-D9) held in hot/humid climate (approximately 31 degrees C dry temperature and 76 % relative humidity). Each day of the competition, heart rate (HR) was recorded every 15 s, tympanic temperature (Ttym) was recorded before exercise and immediately at the end of each stage, and body mass loss (BML) was measured by changes in nude body mass at rest and after each stage. Blood lactate concentration [La] was measured at rest and 5 min after each stage. Venous blood samples were collected before the competition and on the 4 th and 8 th days (D4, D8) for hematological and serum determinations and biochemical analyses. No significant differences were found in cardiac, thermoregulatory, or [La] parameters at rest over the 9 days. The subjects spent 31 +/- 6 % of their time below the lactate threshold (LT), 52 +/- 8 % between LT and the onset of blood lactate accumulation (OBLA), and 18 +/- 6 % above OBLA. The increase in Ttym at D3 (0.48 +/- 0.3 degrees C) was significantly lower (p < 0.05) than at D1, D4, D5, and D6. No difference was found for BML between the different stages. Significant increases (p < 0.05) were observed in monocytes at D8 vs. D4 and pre-race values (D0) and in serum Cl-concentration at D4 vs. D0 and D8 (p < 0.05). A significant reduction was observed in mean corpuscular hemoglobin concentration (MCHC) at D8 and D4 vs. D0 (p < 0.01). No difference was found in other blood parameters at D0, D4, or D8. Taken together, these results suggest that a consecutive 9-day cycle competition in hot/humid climate did not alter homeostasis at rest in acclimated well-trained cyclists. No major effect of repeated cycling stages on thermoregulatory and blood parameters was observed during the Tour de Guadeloupe. Further research is needed to compare the cardiac adaptations of natives to tropical climate and un-acclimated subjects during long-duration exercise.

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The aim of this study was to establish the percentage of sickle cell trait (SCT) carriers among French West Indian sprinters selected for the French National Team in 2000. The investigation determined the number of SCT carriers and the number of national records they had established. Sixteen athletes were indexed (6 males and 10 females). The athletes were within the ranges of 20-33 years, 161-186 cm and 60-80 kg. The results showed the presence of SCT carriers in this population among whom three were SCT carriers (2 males and 1 female) (18.75%). Moreover, there is a significantly higher percentage of titles and records held by the SCT carriers (38.6% and 50%, respectively). In conclusion, this study shows that sickle cell trait carriers are able to perform sprint exercises at the highest levels, and it further indicates that brief and explosive exercise involving mainly the alactic anaerobic metabolism may be enhanced by HbS.

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AIM: The aim of the present study was to determine the effect of tropical climate (i.e., hot and humid) on performance during multiple jump-and-reach tests. METHODS: Fourteen male basketball players volunteered to perform 2 randomized series of jump-and-reach tests, which consisted of a jump-and-reach test every 15 sec for 5 min (21 jump-and-reach tests) in two thermal conditions: tropical (TR, 30.4 degrees C, 70% rh) and thermoneutral (TN, 23.1 degrees C, 53% rh). During each test, lactate concentration [La(-)], tympanic temperature (Tty), sweat rate (SR), heart rate (HR), and performance (height: H) were noted at rest, during exercise and recovery. Two hours of recovery separated the TN and TR tests. RESULTS: There were no significant differences in mean height, maximal height or the kinetics between TN and TR. Both conditions induced an increase in height over time (time effect: p<0.002). There were no significant differences in [La(-)] at rest or during exercise or recovery in the 2 conditions. Both conditions induced an increase in [La(-)] (time effect: p<0.002). There was a tendency toward a higher mean [La(-)] during TR than TN (situation effect, p<0.07). However, compared to resting values, [La(-)] values were significantly increased only in TR and not in TN. Tty, was significantly greater (p<0.001) at rest and during exercise and recovery in TR than in TN. SR and HR were also significantly greater at rest and during exercise and recovery in TR (p<0.001 for SR and HR). CONCLUSION: We conclude that tropical climate affects physiological responses without improving or decreasing performance during successive jump tests.

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BACKGROUND: The aim of the present study was to determine the best jump power equation in the evaluation of elite volleyball players using both the force platform and peak power equations. METHODS: Nine elite volleyball players and nine sedentary subjects performed counter-movement jump tests on a force platform. RESULTS: Peak power and height were greater in the volleyball players than in the sedentary subjects, whatever the method used. The results demonstrated that the peak power values obtained on the force platform and those scored from the equations of Lewis, Harman and Sayers et al. were correlated when the whole sample was taken into account. However, a significant equation x level interaction (p<10(-4)) indicated different behaviour as a function of performance level. In sedentary subjects, peak power was significantly underestimated using the Lewis equation (943+/-162 W; p<10(-4)) and did not differ using both the Harman (3004+/-563 W) and Sayers (3400+/-604 W) equations when compared to the peak power noted with the force platform (3372+/-532 W). In contrast, in volleyball players, peak power was underestimated using the three equations (1246+/-78 W, p<10(-4); 4314+/-216 W, p<0.001; 4607+/-251, p<0.005; for the Lewis, Harman and Sayers equations, respectively, versus 5355+/-522 W for the force platform). CONCLUSIONS: The results of the present study demonstrate the difficulty in choosing the most relevant equation in the jump power calculation.

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The aim of the present study was to assess the performance of subjects with sickle cell trait (SCT) during brief and explosive exercise involving mainly anaerobic metabolism. One hundred and ninety-six black subjects underwent SCT screening, which revealed the presence of 16 subjects with SCT and 180 subjects with normal hemoglobin (HbAA). All subjects performed four tests: 1) a 100-m sprint, 2) a long-jump, 3) a Leger-Boucher shuttle test and 4) a jump-and-reach test. A control group (n = 18) selected from the 180 subjects with HbAA was matched according to the sex, age, weight and height of the SCT subjects (SCTs). The performances of the SCTs (n = 16) were compared with those of the control group. The performances were similar between the SCTs and control group for the sprint test, long-jump and the Leger-Boucher shuttle test. There was, however, a significant difference for the jump-and-reach test between the two groups: the SCTs (i. e., males plus females, and males and females considered separately) reached a significantly greater height (p < 0.05) than the matched subjects of the control group (63.7 +/- 3.6 vs. 58.6 +/- 3.1 cm, 72.3 +/- 3.9 vs. 67.1 +/- 2.4 cm and 52.7 +/- 3.2 vs. 45.3 +/- 2.0 cm for SCTs versus non-SCTs, for the group, the males and the females, respectively). The results of the present study suggest that the performance of brief and explosive exercise may be enhanced by HbS.

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