Exercise-induced bronchoconstriction and atopy in Tunisian athletes.

BACKGROUND: This study is a cross sectional analysis, aiming to evaluate if atopy is as a risk factor for exercise induced bronchoconstriction (EIB) among Tunisian athletes. METHODS: Atopy was defined by a skin prick test result and EIB was defined as a decrease of at least 15% in forced expiratory volume in one second (FEV1) after 8-min running at 80-85% HRmaxTheo. The study population was composed of 326 athletes (age: 20.8 +/- 2.7 yrs - mean +/- SD; 138 women and 188 men) of whom 107 were elite athletes. RESULTS: Atopy was found in 26.9% (88/326) of the athletes. Post exercise spirometry revealed the presence of EIB in 9.8% of the athletes including 13% of the elite athletes. Frequency of atopy in athletes with EIB was significantly higher than in athletes without EIB [62.5% vs 23.1%, respectively]. CONCLUSION: This study showed that atopic Tunisian athletes presented a higher risk of developing exercise induced bronchoconstriction than non-atopic athletes.

Effect of energy expenditure and training status on leptin response to sub-maximal cycling.

We examined the leptin response and related hormones during and after two sub-maximal exercise protocols in trained and untrained subjects. During this study, plasma concentrations of leptin [Lep], insulin [I], cortisol [C], growth hormone [GH], glucose [G] and lactate [La] were measured. 7 elite volleyball trained players (TR) and 7 untrained (UTR) subjects (percent body fat: 13.2 ± 1.8 versus 15.7 ± 1.0, p < 0.01, respectively) were examined after short and prolonged sub-maximal cycling exercise protocols (SP and PP). Venous blood samples were collected before each protocol, during, at the end, and after 2 and 24 h of recovery. SP and PP energy expenditures ranged from 470 ± 60 to 740 ± 90 kcal for TR and from 450 ± 60 to 710 ± 90 kcal for UTR, respectively. [Lep] was related to body fat percentage and body fat mass in TR (r = 0. 84, p < 0.05 and r = 0.93, p < 0.01) and in UTR (r = 0.89, p < 0.01 and r = 0.92, p < 0. 01, respectively). [Lep] did not change significantly during both protocols for both groups but was lower (p < 0.05) in all sampling in TR when compared to UTR. Plasma [I] decreased (p < 0.01) and [GH] increased (p < 0.01) significantly during both SP and PP and these hormones remained lower (I: p < 0.01) and higher (GH: p < 0.01) than pre-exercise levels after a 2-h recovery period, returning to base-line at 24-h recovery. Plasma [La] increased (p < 0.01) during both protocols for TR and UTR. There was no significant change in [C] and [G] during and after both protocols for all subjects. It is concluded that 1) leptin is not sensitive to acute short or prolonged sub-maximal exercises (with energy expenditure under 800 kcal) in volleyball/ anaerobically trained athletes as in untrained subjects, 2) volleyball athletes showed significantly lower resting and exercise leptin response with respect to untrained subjects and 3) it appears that in these anaerobically trained athletes leptin response to exercise is more sensitive to the level of energy expenditure than hormonal or metabolic modifications induced by acute exercise. Key pointsTrials concerning acute exercise and leptin indicated discrepant results.Acute exercise with energy expenditure higher than 800 kcal can decrease leptinemia.Elite volleyball players presented decreased leptin levels than untrained subjects.

Physical activity patterns and estimated daily energy expenditures in normal and overweight tunisian schoolchildren.

Our aim was to test the normality of physical activity patterns and energy expenditures in normal weight and overweight primary school students. Heart rate estimates of total daily energy expenditure (TEE), active energy expenditure (AEE), and activity patterns were made over 3 consecutive school days in healthy middle-class Tunisian children (46 boys, 44 girls, median age (25(th)-75(th)) percentile, 9.2 (8.8-9.9) years. Our cross-section included 52 students with a normal body mass index (BMI) and 38 who exceeded age-specific BMI limits. TEE, AEE and overall physical activity level (PAL) were not different between overweight children and those with a normal BMI [median values (25(th)-75(th)) 9.20 (8.20-9.84) vs. 8.88 (7.42-9.76) MJ/d; 3.56 (2.59-4.22) vs. 3.85 (2.77-4.78) MJ/d and 1.74 (1.54-2.04) vs. 1.89 (1.66-2.15) respectively]. Physical activity intensities (PAI) were expressed as percentages of the individual's heart rate reserve (%HRR). The median PAI for the entire day (PAI24) and for the waking part of day (PAIw) were lower in overweight than in normal weight individuals [16.3 (14.2-18.9) vs. 20.6 (17.9-22.3) %HRR, p < 0.001) and 24.8 (21.6-28.9) vs.26.2 (24.5-30.8) %HRR, p < 0.01], respectively. Overweight children allocated more of their day to sedentary pursuits [385 (336-468) vs 297 (235-468) min/d, p < 0.001], and less time to moderate physical activity [381(321-457) vs. 460 (380-534) min/d, p < 0.01]. Nevertheless, because of the greater energy cost of a given task, total and active daily energy expenditure did not differ from those with a normal BMI. Key pointsThe physical activity intensity for the entire day (PAI24) and for the waking part of day (PAIw) were lower in overweight than in normal weight individuals.However, because the energy cost of activity is greater in those who are overweight, they do not differ in total energy expenditure or in active energy expenditure.Normal children spend more time in moderate activity and less time in sedentary pursuits than overweight children.

Leptin, its implication in physical exercise and training: a short review.

Leptin, a hormone synthesized by fat tissue had been noted to regulate energy balance and metabolism and thus to influence body weight. The influence of acute exercise and chronic exercise training on circulating leptin and its relationship with hormonal and metabolic changes that induce energy balance are presented. Research that has examined the influence of exercise under various experimental conditions on leptin and the conflicts in the literature are presented. It appears that a significant caloric perturbation (> 800 kcals) is necessary for acute exercise to result in a significant reduction in leptin. In contrast, exercise training can result in a leptin decline but typically this manifests a reduction in adipose tissue stores. In addition, future directions are presented. Key PointsPhysical exercise and training have both inhibitory and stimulatory effects on leptin.Exercise with energy expenditure higher than 800 kcal can decrease leptinemia.Acute training may cause a decline in circulating leptin levels.

Parathyroid hormone and physical exercise: a brief review.

Parathyroid hormone (PTH) is the major hormone regulating calcium metabolism and is involved in both catabolic and anabolic actions on bone. Intermittent PTH exposure can stimulate bone formation and bone mass when PTH has been injected. In contrast, continuous infusion of PTH stimulates bone resorption. PTH concentration may be affected by physical exercise and our review was designed to investigate this relationship. The variation in PTH concentration appears to be influenced by both exercise duration and intensity. There probably exists a stimulation threshold of exercise to alter PTH. PTH regulation is also influenced by the initial bone mineral content, age, gender, training state, and other hormonal and metabolic factors (catecholamines, lactic acid and calcium concentrations). Key PointsPhysical exercise can improve PTH secretion.PARATHYROID HORMONE HAS BOTH ANABOLIC AND CATABOLIC EFFECTS ON BONE: intermittent treatment of PTH is anabolic whereas continuous treatment is catabolic.