Sleep parameters improvement in PTSD soldiers after symptoms remission.

Eye movement desensitization and reprocessing (EMDR) is a psychotherapy for the treatment of posttraumatic stress disorder (PTSD). It is still unclear whether symptoms remission through EMDR therapy is associated with a beneficial effect on one of the PTSD symptoms, sleep disturbance. Our objective was therefore to study sleep parameters before and after symptom remission in soldiers with PTSD. The control group consisted of 20 healthy active duty military men who slept in a sleep lab with standard polysomnography (PSG) on two sessions separated by one month. The patient group consisted of 17 active duty military with PTSD who underwent EMDR therapy. PSG-recorded sleep was assessed 1 week before the EMDR therapy began and 1 week after PTSD remission. We found that the increased REMs density after remission was positively correlated with a greater decrease of symptoms. Also, the number of EMDR sessions required to reach remission was correlated with intra-sleep awakenings before treatment. These results confirm the improvement of some sleep parameters in PTSD after symptoms remission in a soldier's population and provide a possible predictor of treatment success. Further experiments will be required to establish whether this effect is specific to the EMDR therapy.

Influence of a brisk walking program on postural responses in sedentary older women: a randomised trial.

This study analyzes the evolution in kinematic and non-linear stabilometric parameters in elderly sedentary women selected to participate in a brisk walking program. Ninety-four women were randomly selected for a program of 78 sessions over 6 months, with three sessions of 60 min per week. On the force platform, participants were assessed with both eyes opened as well as eyes closed during a period of 51.2 s and the sampling frequency was 40 Hz. The main dependent kinematic variables were the length, stabilogram surface, and the mean position in anteroposterior as well as medio-lateral directions. For the dynamic approach, we have selected the parameters of recurrence quantification analysis, sample entropy, and multiscale entropy. The kinematic and the time series analysis of group × time interactions demonstrated that 6 months of walk-training lacked influence on kinematic postural responses and on dynamical measurements. The weekly brisk walking program was situated on flat ground and consisted of three 60-min weekly sessions lasting 6 months, leading to no significant effect on postural responses. In regards to international recommendations brisk walking is a pertinent exercise. However, in older sedentary women, our study indicated a systemic lack of influence of 6 months' walk-training on flat ground on kinematic postural responses and on dynamical measures obtained by time series analysis.

Effect of a 6-Month Brisk Walking Program on Walking Endurance in Sedentary and Physically Deconditioned Women Aged 60 or Older: A Randomized Trial.

BACKGROUND: Walking endurance is a predictor of healthy ageing. OBJECTIVE: To examine if a 6-month brisk walking program can increase walking endurance in sedentary and physically deconditioned older women. TRIAL DESIGN: Randomized controlled trial. SETTING: Women recruited from public meetings aimed at promoting physical activity in women aged 60 or older. SUBJECTS: 121 women aged 65.7 ± 4.3 years, with sedentary lifestyle (Physical Activity Questionnaire for the Elderly score < 9.4), and a 6-minute walking distance (6MWD) below normal value based on their gender, age, and body weight, and weight. METHODS: Women were randomly assigned to a 150 min/week brisk walking program (two supervised sessions and one session on their own per week) for six months (exercisers) (n=61) or a control group with physical activity allowed freely (n=60). OUTCOME: The primary outcome was relative change in 6MWD. RESULTS: 54/61 exercisers and 55/60 control subjects completed the program and data analysis was possible for 51 exercisers and 47 controls. At baseline, 6MWD was on average 23.1% and 22.5% below age-matched norms in exercisers and controls, respectively. Attendance rate for supervised sessions was 92% in exercisers. The 6MWD increased more significantly in exercisers than in controls (mean increase of 41.5% vs 11.0 %; p<0.0001). Over the 6-month program, 38 exercisers (74.5%) vs 5 controls (10.6%) had a 6MWD over the age-matched norm (p<0.0001). Exercisers with the highest tertile of 6MWD improvement (>46%) were those with baseline lowest values of 6MWD (p=0.001) and highest values of body mass index (BMI) (p<0.01). CONCLUSION: Present results support recommendation that brisk walking programs should be encouraged to improve walking endurance in physically deconditioned women aged 60 or older, especially in those with high BMI.

[Intensive training and menstrual disorders in young female: Impact on bone mass]. / Sport intensif et troubles du cycle chez la jeune femme : retentissement sur la masse osseus.

Participation in recreational physical activity is widely acknowledged to provide significant health benefits. Conversely, intense training imposes several constraints, such as intermittent or chronic metabolic and psychogenic training stressors and maintenance of very low body fat to maximize performance. Adolescent and adult athletic women are therefore at risk of overtraining and/or poor dietary intake, which may have several consequences for endocrine function particularly on hypothalamic-pituitary-gonadal axis. Female athletes, particularly those participating in sports needing leanness or low body weight, present a high prevalence of menstrual disorders with clinical manifestations ranging from delayed menarche, oligomenorrhea to primary and secondary amenorrhea. A high degree of variability according to the type of sport and the intensity of the practice is however observed. Exercise-related reproductive dysfunction may have some consequences for growth velocity and peak bone mass acquisition during adolescence and bone pathologies in adults. Recent findings highlight the endocrine role of adipose tissue and energy balance in the regulation of homeostasis and reproductive function. A better understanding of the mechanisms whereby intense training affects the endocrine systems may orient research to develop innovative strategies probably based on individualized nutritional approach to improve the medical care of these female athletes and protect their reproductive function.

Influence of a brisk walking program on isokinetic muscular capacities of knee in sedentary older women.

This study analyzed the evolution in peak torque (PT) and mean power (MP) isokinetic parameters in the quadriceps and hamstring muscles of elderly sedentary women who were randomly selected to participate in a brisk walking program for 6 months. The 121 sedentary women of this study presented a mean score of 5.3 (±1.7) on the Physical Activity Questionnaire for the Elderly and covered 86 % of the theoretical distance on the 6-min walk test. The isokinetic evaluation was performed on both sides at 60°/s and 180°/s. PT and MP were selected for analysis. Women in the trained group (n = 61) participated in a program of 78 sessions over 6 months with three sets of 60 min of exercise per week. For this group, heart rate, time and distance were, respectively, 125.2 bt/min (±10), 37.9 min (±4.2) and 3756.3 m (±445.4). The analysis of the group × time interaction demonstrated an increase in the PT of the dominant-side hamstrings (p < 0.001). In the trained group, we observed a significant increase in PT at 60°/s for the hamstrings on both sides (0.01 < p < 0.02) and a significant increase in MP for the hamstrings at 60°/s on the nondominant side (p < 0.05). The study indicates a minor, though significant, influence of a brisk walking program on the peak torque and mean power of the quadriceps and hamstring muscles in sedentary women over 60 years.

Congenital taurine deficiency in mice is associated with reduced sensitivity to nociceptive chemical stimulation.

The amino acid taurine is required for development and functioning of the central and peripheral nervous system where it exerts osmoregulatory, neuromodulatory and anti-apoptotic actions. It is subject to cellular import by the taurine transporter slc6a6. Absence of the transporter and consequently, absence of taurine leads to several neurologic deficits and sensory losses. In a slc6a6 knock-out mouse model, consequences of congenital taurine deficiency were assessed in nociceptive sensory processes. The formalin assay, hot plate assay, and summated generator potentials in response to local nociceptive stimulation with gaseous CO2 were applied. Reduced responsiveness of slc6a6(-/-) mice to nociceptive stimulation was observed in particular to chemical nociceptive stimuli. Scl6a6 knock-out mice spent significantly less time licking the formalin injected paw and displayed smaller amplitudes of the nociceptive nasal mucosa potentials than wild-type mice (p=0.002 and 0.01 respectively). In contrast, withdrawal latencies on a hot plate did not significantly differ, suggesting that intracellular taurine deficits lead in particular to a hyposensitivity of nociceptive sensory neurons sensitive to noxious chemical stimulation. As hereditary absence of taurine affects biological processes of anatomical structure development, the altered nociceptive responses likely reflect consequences of compromised peripheral nervous system development.

Dexamethasone modulates expression of genes involved in the innate immune system, growth and stress and increases susceptibility to bacterial disease in Senegalese sole (Solea senegalensis Kaup, 1858).

Cortisol, the main glucocorticoid in fish, undertakes pleiotropic biological effects in response to stressors to maintain homeostasis. It can exert several actions on the immune system, growth and cellular metabolism, establishing a fine-tune regulation stress response and cross-talk interactions with other regulatory pathways. In this study, we investigated a causal relationship between high levels of glucocorticoids and susceptibility to pathogens and modification of gene expression profiles in Senegalese sole. For this purpose, we carried out two experiments using post-metamorphic individuals (21 days after hatching) that were exposed to dexamethasone (DXM), a potent glucocorticoid, in order to mimic cortisol effects. We quantified transcript levels of a wide set of genes involved in innate immune system (g-type lysozyme and hepcidin (hamp1)), HPI axis (crf, crfbp, pomcα, pomcß, gr1 and gr2), HPT axis (tgb), cellular stress defense system (hsp70 and hsp90aa), GH/IGF axis (igf-I and igf-Ir) and the neuropeptide trh. Short-term exposure to 0.1, 1 and 10 ppm DXM provoked a reduction of pomcß transcripts and an increase of crfbp mRNAs in a dose-dependent manner at 48 and 72 h after treatment. Moreover, g-type lysozyme transcript levels decreased significantly at 72 h whereas hamp1 mRNA levels increased at 48 h after exposure. Long-term DXM treatment (10 ppm DXM) affected negatively weight of soles (~20% lower than controls). Moreover, reduced mRNA levels were observed for pomcß after 1 week and igf-I and hamp1 after 2 weeks. In contrast, crfbp and crf increased mRNA levels after 2 weeks. hsp70 exhibited a dual response increasing transcript levels at 1 week after treatment and reducing thereafter. No significant changes in gene expression were observed at any time during this study for tgb, trh, hsp90aa, pomcα, gr1 and gr2. Finally, a challenge experiment using the pathogen Photobacterium damselae subsp piscicida confirmed earlier and higher mortalities in DXM-treated animals. Taken together, these data indicate that a prolonged exposure to DXM increases the susceptibility to pathogens and reduces growth. Moreover, DXM can trigger a wide cellular response modulating the expression of genes involved in the innate immune system, HPI and GH/IGF axes as well as cellular stress defense. These results are highly valuable to evaluate responses associated to aquaculture stressful conditions and discriminate specific glucocorticoid-mediated effects.

Are n-3 PUFA dietary recommendations met in in-hospital and school catering?

BACKGROUND: Literature provides compelling evidence for the health benefits of n-3 polyunsaturated fatty acids (PUFA) consumption and low n-6/n-3 ratio, in particular, on inflammation and metabolic syndrome prevention and treatment. Consequently, recommendations were established for adequate n-3 PUFA supplies in the general population. The aim of our study was to evaluate the fatty acid (FA) profile in collective catering in relation to those recommendations. METHODS: We obtained composition of lunches provided by the Township of Lille (France) to children and adults, and of "standard", "low-fat" and "for diabetic" menus from the catering service of St Luc university hospital (Brussels, Belgium). The average proportions of fish, meat, oils, and dairy were used to estimate total, saturated, monounsaturated and polyunsaturated (n-6 and n-3) FA contents. We used official tables of foodstuffs composition provided by the French Agency for Food Safety, the project "Nutritional Composition of Aquatic Products", the French Institute for Nutrition, and the USDA National Nutrient Database for Standard Reference. French guidelines were taken as reference for daily recommended intakes. RESULTS: n-3 PUFA content in lunches provided by municipal catering and in in-hospital menus were slightly below recommended intakes. In the latter, n-3 PUFA enriched margarine contributed for 50% to daily intakes. Despite, the n-6/n-3 ratio was too high, especially in municipal catering (around 20), related to excessive n-6 PUFA supply. CONCLUSIONS: Our results highlight that meeting n-3 PUFA nutritional recommendation remains challenging for collective catering. A detailed analysis of provided menus represents a powerful tool to increase awareness and foster improvement in practice.

Maternal perinatal undernutrition has long-term consequences on morphology, function and gene expression of the adrenal medulla in the adult male rat.

Epidemiological studies suggest that maternal undernutrition sensitises to the development of chronic adult diseases, such as type 2 diabetes, hypertension and obesity. Although the physiological mechanisms involved in this 'perinatal programming' remain largely unknown, alterations of stress neuroendocrine systems such as the hypothalamic-pituitary-adrenal (HPA) and sympathoadrenal axes might play a crucial role. Despite recent reports showing that maternal perinatal undernutrition disturbs chromaffin cells organisation and activity in male rats at weaning, its long-term effects on adrenal medulla in adult animals are unknown. Using a rat model of maternal perinatal 50% food restriction (FR50) from the second week of gestation until weaning, histochemistry approaches revealed alterations in noradrenergic chromaffin cells aggregation and in cholinergic innervation in the adrenal medulla of 8-month-old FR50 rats. Electron microscopy showed that chromaffin cell granules exhibited ultrastructural changes in FR50 rats. These morphological changes were associated with reduced circulating levels and excretion of catecholamines. By contrast, catecholamine plasma levels were significantly increased after a 16 or 72 h of fasting, indicating that the responsiveness of the sympathoadrenal system to food deprivation was accentuated in FR50 adult rats. Among 384 pituitary adenylate cyclase-activating polypeptide-sensitive genes, we identified 129 genes (33.6%) that were under expressed (ratio < 0.7) in FR50 animals. A large number of these genes are involved in cytoskeleton remodelling and vesicle trafficking. Taken together, our results show that maternal perinatal undernutrition programmes adrenomedullary function and gene expression in adult male rats. Because catecholamines contribute to metabolic homeostasis, as well as arterial blood pressure regulation, the alterations observed in the adrenal medulla of adult male FR50 rats may participate in the programming of chronic adult diseases.

In peripubertal girls, artistic gymnastics improves areal bone mineral density and femoral bone geometry without affecting serum OPG/RANKL levels.

UNLABELLED: Peripubertal artistic gymnasts display elevated areal bone mineral density at various bone sites, despite delayed menarche and a high frequency of menstrual disorders, factors that may compromise bone health. The concomitant improvement in femoral bone geometry and strength suggested that this type of physical activity might have favourable clinical impact. INTRODUCTION: The purpose of this study is to evaluate the effect of artistic gymnastics (GYM) on areal bone mineral density (aBMD), femoral bone geometry and bone markers and its relationship with the osteoprotegerin (OPG)/rank-ligand (RANKL) system in peripubertal girls. METHODS: Forty-six girls (age 10-17.2 years) were recruited for this study: 23 elite athletes in the GYM group (training 12-30 h/week, age at start of training 5.3 years) and 23 age-matched (± 6 months; leisure physical activity ≤ 3 h/week) controls (CON). The aBMD at whole body, total proximal femur, lumbar spine, mid-radius and skull was determined using dual-X-ray absorptiometry. Hip structural analysis (HSA software) was applied at the femur to evaluate cross-sectional area (CSA, cm(2)), cross-sectional moment of inertia (CSMI, cm(4)), and the section modulus (Z, cm(3)) and buckling ratio at neck, intertrochanteric region and shaft. Markers of bone turnover and OPG/RANKL levels were also analysed. RESULTS: GYM had higher (5.5-16.4%) non-adjusted aBMD and adjusted aBMD for age, fat-free soft tissue and fat mass at all bone sites, skull excepted and the difference increased with age. In the three femoral regions adjusted for body weight and height, CSA (12.5-18%), CSMI (14-18%), Z (15.5-18.6%) and mean cortical thickness (13.6-21%) were higher in GYM than CON, while the buckling ratio (21-27.1%) was lower. Bone markers decreased with age in both groups and GYM presented higher values than CON only in the postmenarchal period. A similar increase in RANKL with age without OPG variation was observed for both groups. CONCLUSION: GYM is associated not only with an increase in aBMD but also an improvement in bone geometry associated with an increase in bone remodelling. These adaptations seem to be independent of the OPG/RANKL system.

Basal plasma leptin levels in healthy elderly males are related to physical fitness without impact on bone metabolism.

AIM: Investigated the relationship between leptin levels or bone remodelling and physical fitness level in healthy elderly participants. METHODS: Twenty women and 18 men (mean age 72.7 years, range 59-90) performed a maximal incremental exercise test to evaluate their maximal oxygen uptake (VOmax). Basal blood concentrations of bone biochemical markers (BM) and leptin were analysed. RESULTS: Women presented higher values of leptin than men (+34.7%, P=0.024), but no difference related to gender was observed for the other biological parameters. Leptin levels were positively correlated with Body Mass Index (BMI) in both genders. Whether adjusted or not for BMI, leptin was negatively correlated with VOmax only in men (r=-0.55, P=0.02 and r=-0.57, P=0.01, respectively). No relationship between VOmax or leptin and BM was observed, except for leptin and osteocalcin in men (r=-0.66, P=0.015). CONCLUSION: Our data suggest that neither physical fitness nor leptin level seems to have a noticeable effect in the regulation of bone cell activity in healthy elderly participants. In this specific population, physical fitness plays a crucial role on leptin secretion, independently of BMI variation, and this action appears to be sex-dependent.

Dietary lipids and NAFLD: suggestions for improved nutrition.

Non-alcoholic fatty liver disease (NAFLD) ranges from steatosis and hepatic insulin resistance to non-alcoholic steatohepatitis (NASH), advanced fibrosis and cirrhosis. NAFLD is now considered as the hepatic manifestation of the metabolic syndrome, and both are triggered by mechanisms including inflammation, lipid overload and oxidative stress in adipose tissue and liver. Despite accumulation of numerous data on NAFLD physiopathology, therapeutic modulation of the pathways involved appear insufficiently efficient or associated with serious adverse effects. The increased prevalence of NAFLD and metabolic syndrome during the last decades was associated with deep modifications of dietary habits, especially increased fat intakes. Recent literature provides clues of increased saturated (SFA) and n-6 polyunsaturated fatty acids (PUFA) as well as reduced n-3 PUFA in the diet of NAFLD and NASH patients. Indeed, strong data support the detrimental role of high SFA and n-6/n-3 ratio as well as low monounsaturated fatty acids (MUFA) and n-3 PUFA on metabolic parameters, which are ameliorated by administration of n-3 PUFA and MUFA. Despite governments and health associations having revised their recommendations for n-3 PUFA intakes upward during the last decade, those are still inferior to levels proved of therapeutic efficiency and are still not reached in the general population. This short review discusses these issues and provides consequent pragmatic suggestions for enhanced dietary measures for prevention of NAFLD and metabolic syndrome in the general population.

Desynchronization of daily rest-activity rhythm in the days following light propofol anesthesia for colonoscopy.

Anesthesia and surgery are associated with fatigue and sleep disorders, suggestive of disturbance of the circadian rest-activity rhythm. Previous studies on circadian rhythm disturbance were focused on patients undergoing general anesthesia associated with surgery. This does not permit one to draw valid conclusions about the effects of general anesthesia per se on circadian rhythms. Our study was set up to determine the impact of a hypnotic dose of propofol on the circadian rest-activity rhythm in humans under real-life conditions. Seventeen healthy subjects scheduled to receive light propofol anesthesia for ambulatory colonoscopy were investigated. Their rest-activity rhythms were assessed using actigraphic monitoring. Diurnal rest was increased, whereas nocturnal sleep was unchanged in the days following anesthesia. Nonparametric analyses showed a decrease in the strength of coupling of the rhythm to stable environmental zeitgebers and increase of fragmentation of the rhythm after anesthesia. Light general anesthesia itself impairs synchronization of the circadian rest-activity rhythm to local time in patients by acting directly on the circadian clock.

Response of calciotropic hormones and bone turnover to brisk walking according to age and fitness level.

Ageing is associated with a gradual bone loss and physical activity has been suggested as practical strategy for a non-pharmacological prevention of osteoporosis. However, until now, the specific mechanism by which physical activity affects bone tissue is not thoroughly understood. The aim of this study was to evaluate the effect of strenuous exercise on bone metabolism as a function of age and fitness level. Eighteen physically highly active elderly participants (mean age 71.7+/-7.3 years, HAcEl group), 18 moderately active elderly participants (mean age 71.9+/-8.6 years, ModEl group) and 9 young physically active participants (mean age 25.8+/-2.3 years, AcYo) participated in this study. Concentrations of plasma ionised calcium (iCa), serum parathyroid hormone (iPTH), 25-hydroxy-vitamin D [25(OH)D], and 1,25-dihydroxy-vitamin D3 [1,25(OH)(2)D3] as well as the bone biochemical markers type-I collagen C-telopeptide (CTX) for bone resorption and osteocalcin (OC) and bone alkaline phosphatase (B-ALP) for bone formation, were analyzed before and after a maximal incremental exercise test. In all groups, iCa decreased significantly (p<0.05 for ModEl and AcYo and p<0.001 for HAcEl) while iPTH increased significantly (p<0.01 for ModEl and HAcEl and p<0.001 for AcYo) after exercise. The levels of 1,25(OH)(2)D3, OC and CTX remained unchanged, while 25(OH)D decreased only in HAcEl group while B-ALP increased in ModEl group. In conclusion, strenuous exercise disturbed calcium homeostasis, mainly the iCa/iPTH equilibrium independently of gender, age or fitness level of the participants while no immediate effect on bone turnover was observed.

Maternal perinatal undernutrition impairs chromaffin cells proliferation in the postnatal rat.

Numerous data show that malnutrition during early life programs chronic diseases in adulthood. Many of these disorders may result from alterations in the development of neuroendocrine systems, such as the hypothalamo-pituitary-adrenal axis and the sympathoadrenal system. We have previously reported that maternal 50% food restriction during late pregnancy and lactation reduces adrenal weight and impairs chromaffin cell differentiation in male rats at weaning. In addition, maternal undernutrition modifies the expression of several genes involved in proliferation and apoptosis. This study therefore investigated the impact of maternal food restriction on adrenal cell growth in the late postnatal rat. Histological analysis showed that the number of proliferating chromaffin cells assessed by nuclear labelling with BrdU was reduced by 45%, whereas the level of apoptosis visualised by caspase-3 immunoreactivity was increased by 340% in adrenal medulla of offspring from undernourished mothers. In contrast, maternal food restriction did not affect proliferation and apoptosis in cortical cells of rats. These developmental changes were associated with overexpression of TGFbeta2. These data show that perinatal undernutrition impairs the balance between chromaffin cell proliferation and apoptosis. These modifications may lead to "malprogramming" of adrenal medulla development, which could contribute to the pathogenesis of chronic diseases in adulthood.

Competitive season of triathlon does not alter bone metabolism and bone mineral status in male triathletes.

This longitudinal study evaluated the effects of a triathlon season on bone metabolism and hormonal status. Seven male competitive triathletes (mean age 19.3 years, range 18 - 20) with 5.0 +/- 0.3 years of competition experience were tested twice during the season: at the beginning of training and 32 weeks later. Total and regional bone mineral density (BMD) was determined by dual-energy X-ray absorptiometry, while bone turnover was evaluated by specific biochemical markers: bone-specific alkaline phosphatase (B-ALP), osteocalcin, and urinary type I collagen C-telopeptide. In addition, sexual, calciotropic and somatotropic hormones were also analyzed. After 32 weeks, a BMD increase was found at the lumbar spine (1.9 %; p = 0.031) and skull (3.1 %; p = 0.048), while no variation was observed for total body or at the proximal femur. The B-ALP level decreased (-23.2 %; p = 0.031), but no variation was found for the other bone markers. 1.25 (OH) (2)D3, IGF-1 and the bioavailability IGF-1 index (IGF-1/IGFBP-3) increased by 18.3 % (p = 0.047), 29 % (p = 0.048), 33 % (p = 0.011), respectively, while PTH, testosterone, IGFBP-3 and cortisol concentrations were unchanged. In conclusion, the triathlon season had a moderately favourable effect on BMD, although a slowing down of bone formation activity was observed. No variation in hormonal levels was observed that could have limited the effects of exercise on bone tissue.

Asthma and exercise-induced bronchoconstriction in amateur endurance-trained athletes.

High-level endurance training contributes to the development of asthma and exercise-induced bronchoconstriction but the effect of moderate endurance training on airway function remains to be determined. The aim of this study was to evaluate the prevalence of physician-diagnosed asthma and/or exercise-induced bronchoconstriction in moderately endurance-trained athletes. Ninety-five Mediterranean amateur endurance-trained athletes filled out a questionnaire about respiratory disorders and underwent a resting spirometry. Mean training volume was 10 h per week. The prevalence of asthma was found to be 4.2 %. All the athletes with asthma plus another one (5.3 %) reported having exercise-induced bronchoconstriction. These percentages are in the same range as those from the general population and much lower than those observed in elite endurance athletes. In contrast to elite athletes, our amateur endurance-trained athletes seem not exposed to a higher risk of asthma or exercise-induced bronchoconstriction than the general population. We suggest that 10 h per week of moderate endurance training in a temperate climate area does not lead to respiratory disease.

Caffeine or melatonin effects on sleep and sleepiness after rapid eastward transmeridian travel.

We measured the effects of slow-release caffeine (SRC) and melatonin (Mlt) on sleep and daytime sleepiness after a seven-time zone eastbound flight. In a double-blind, randomized, placebo-controlled study, each of three groups of nine subjects was given either 300 mg SRC on recovery day 1 (D1) to D5 (0800) or 5 mg Mlt on preflight D-1 (1700), flight day D0 (1600), and from D1 to D3 (2300), or placebo (Pbo) at the same times. Nighttime sleep was evaluated by polysomnography and daytime sleepiness from measurements of sleep latencies and continuous wrist actigraphy. Compared with baseline, we found a significant rebound of slow-wave sleep on night 1 (N1) to N2 under Pbo and Mlt and a significant decrease in rapid eye movement sleep on N1 (Pbo) and N1-N3 (Mlt). Sleepiness was objectively increased under Pbo (D1-D6) and Mlt (D1-D3). SRC reduced sleepiness but also tended to affect sleep quality until the last drug day. In conclusion, both drugs have positive effects on some jet lag symptoms after an eastbound flight: SRC on daytime sleepiness, and Mlt on sleep.

Maximal oxygen uptake and power of lower limbs during a competitive season in triathletes.

BACKGROUND: In order to study the effect of a competitive triathlon season on maximal oxygen uptake (VO2max), aerobic power (AeP) and anaerobic performance (AnP) of the lower limbs, eight triathletes performed exercise tests after: (1) a pre-competition period (Pre-COMP) (2) a competitive period (COMP), and (3) a low (volume and intensity) training period (Post-COMP). The tests were a vertical jump-and-reach test and an incremental exercise test on a cycle ergometer. Ventilatory data were collected every minute during the incremental test with an automated breath-by-breath system and the heart-rate was monitored using a telemetric system. RESULTS: No changes in VO2max were observed, whereas AeP decreased after Post-COMP compared to Pre-COMP and COMP and AnP decreased during COMP compared to Pre-COMP and Post-COMP. In addition, second ventilatory threshold (VT2) and power output at first ventilatory threshold (VT1) and VT2 decreased after Post-COMP. CONCLUSION: This study showed that six weeks of low volume and intensity of training is too long a period to preserve adaptations to training, although a stable maximal oxygen uptake throughout the triathlon season was observed. Moreover, the AnP decrease during COMP was probably in relation with the repetitive nature of the training mode and/or triathlon competitions.