Evolutionary history of the ADRB2 gene in humans

No abstract available

Genetic influence on East African running success

East African athletes now dominate international distance running events from the 800 m to the marathon. Explanations for their phenomenal success have included optimal environmental conditions for developing distance running performance, psychological advantage and advantageous physiological characteristics. It is well established that genetics plays a role in determining inter-individual differences in exercise performance and adaptation to training stimuli. It is not known, however, to what extent inter-population differences (i.e. between ‘races’ and/or ethnic groups) in exercise performance can be attributed to genetics. There have been considerations that ‘black’ athletes are genetically adapted towards performance, given the concurrent success of athletes of West African ancestry in sprint events. However, the current notion of ‘race’ is not universally accepted, and genetic differences within and between populations are not clearly delineated by geographical or ethnic categorizations. Recent findings from mitochondrial DNA show that the populations from which Ethiopian athletes are drawn have not been isolated populations and are not genetically distinct from other Ethiopians. Y-chromosome analysis of the same population shows concurrent results, although some differences are present between athletes and the general Ethiopian population, suggesting an influence of the Y chromosome on athlete status in Ethiopia. It is concluded that there may be a role for genetics in the success of East African athletes; however, any genetic component to their success is unlikely to be limited to East Africans and is more likely to be found in other populations. At present it is unjustified to implicate a role for genetics in the success of East African runners when no genes have been identified as being important to their performance

Food and macronutrient intake of elite Ethiopian distance runners

Background: Explanations for the phenomenal success of East African distance runners include unique dietary practices. The aim of the present study was to assess the food and macronutrient intake of elite Ethiopian distance runners during a period of high intensity exercise training at altitude and prior to major competition. Methods: The dietary intake of 10 highly-trained Ethiopian long distance runners, living and training at high altitude (approximately 2400 m above sea level) was assessed during a 7 day period of intense training prior to competition using the standard weighed intake method. Training was also assessed using an activity/training diary. Results: Body mass was stable (i.e., was well maintained) over the assessment period (pre: 56.7 +/- 4.3 kg vs. post: 56.6 +/- 4.2 kg, P = 0.54; mean +/- SD). The diet comprised of 13375 +/- 1378 kJ and was high in carbohydrate (64.3 +/- 2.6%, 545 +/- 49 g, 9.7 +/- 0.9 g/kg). Fat and protein intake was 23.3 +/- 2.1% (83 +/- 14 g) and 12.4 +/- 0.6% (99 +/- 13 g, 1.8 +/- 0.2 g/kg), respectively. Fluid intake comprised mainly of water (1751 +/- 583 mL), while no fluids were consumed before or during training with only modest amounts being consumed following training. Conclusions: Similar to previous studies in elite Kenyan distance runners, the diet of these elite Ethiopian distance runners met most recommendations of endurance athletes for macronutrient intake but not for fluid intake

The effects of moderate alterations in adrenergic activity on acute appetite regulation in obese women: a randomised crossover trial

Background: Previous evidence has demonstrated that serum leptin is correlated with appetite in combination with, but not without, modest exercise. Aim: The present experiments investigated the effects of exogenous adrenaline and α/β adrenoceptor blockade in combination with moderate exercise on serum leptin concentrations, appetite/satiety sensations and subsequent food intake in obese women. Methods: A total of 10 obese women ((mean ± SEM), age: 50 (1.9) years, body mass index 36 (4.1) kg/m2, waist 104.8 (4.1) cm) participated in two separate, double-blind randomised experimental trials. Experiment 1: moderate exercise after α/β adrenergic blocker (labetalol, 100 mg orally) versus moderate exercise plus placebo; experiment 2: adrenaline infusion for 20 minutes versus saline infusion. Appetite/satiety and biochemistry were measured at baseline, pre- and immediately post-intervention, then 1 hour post-intervention (i.e., before dinner). Food intake was assessed via ad libitum buffet-style dinner. Results: No differences were found in appetite/satiety, subsequent food intake or serum leptin in any of the studies (experiment 1 or experiment 2). In experiment 1, blood glucose was higher (p < 0.01) and plasma free fatty acids lower (p = 0.04) versus placebo. In experiment 2, plasma free fatty acids (p < 0.05) increased after adrenaline versus saline infusion. Conclusions: Neither inhibition of exercise-induced adrenergic activity by combined α/β adrenergic blockade nor moderate increases in adrenergic activity induced by intravenous adrenaline infusion affected acute appetite regulation

the use of technology to protect the health of athletes during sporting competitions in the heat

During the 2019 IAAF World Championships in Athletics in Doha and the 2020 Olympic Games in Tokyo, minimum daily temperatures are expected to be in excess of 30 C. Due to the metabolic demands of the sporting events and the high environmental temperatures, the risk of exertional heat illness (EHI) is significantly higher. Careful planning is needed to ensure that athletes are protected from irreversible long-term health damage, or even death. The greatest benefit to exercise performance is gained after about 2 weeks of heat acclimation. For maximal adaptations to occur, the heat acclimation regime undertaken should closely mimic the environmental and intensity characteristics of the conditions expected during competition. Other acute strategies are available to enhance performance in the heat including the ingestion of cold (~4 C) beverages and the use of iced towels and ice garments; these acute strategies do not replace the need for heat acclimation. The importance of responding quickly to a hyperthermic athlete cannot be understated, as minimizing treatment time will greatly improve the chances of a full recovery. Treatment time can be minimized by notifying medical personnel about the athlete's health status and the extent of any pre-competition heat acclimation strategy. Technology that allows the live transmission of physiological, performance, and biomechanical data to alert medical personnel of potential indicators of EHI should be considered. Prompt recognition of EHI will result in faster and more effective medical treatment which is crucial in protecting the athlete from irreversible and long-term health consequences, including death

Evidence of negative energy balance using doubly labelled water in elite Kenyan endurance runners prior to competition

Previous studies have found Kenyan endurance runners to be in negative energy balance during training and prior to competition. The aim of the present study was to assess energy balance in nine elite Kenyan endurance runners during heavy training. Energy intake and expenditure were determined over 7d using weighed dietary intake and doubly labelled water, respectively. Athletes were on average in negative energy balance (mean energy intake 13 241 (SD 1330) kJ/d v. mean energy expenditure 14 611 (SD 1043) kJ/d; P=0·046), although there was no loss in body mass (mean 56·0 (SD 3·4) kg v. 55·7 (SD 3·6) kg; P=0·285). The calculation of underreporting was 13; (range −24 to +9%) and almost entirely accounted for by undereating (9% (range −55 to +39%)) as opposed to a lack of significant underrecording (i.e. total water intake was no different from water loss (mean 4·2 (SD 0·6) l/d v. 4·5 (SD 0·8) l/d; P=0·496)). Fluid intake was modest and consisted mainly of water (0·9 (SD 0·5) l/d) and milky tea (0·9 (SD 0·3) l/d). The diet was high in carbohydrate (67·3 (SD 7·8) %) and sufficient in protein (15·3 (SD 4·0) %) and fat (17·4 (SD 3·9) %). These results confirm previous observations that Kenyan runners are in negative energy balance during periods of intense training. A negative energy balance would result in a reduction in body mass, which, when combined with a high carbohydrate diet, would have the potential in the short term to enhance endurance running performance by reducing the energy cost of runnin

The Impact of Grounding in Running Shoes on Indices of Performance in Elite Competitive Athletes

The introduction of carbon fiber plate shoes has triggered a plethora of world records in running, which has encouraged shoe industries to produce novel shoe designs to enhance running performance, including shoes containing conductor elements or "grounding shoes" (GS), which could potentially reduce the energy cost of running. The aim of this study was to examine the physiological and perceptual responses of athletes subjected to grounding shoes during running. Ten elite runners were recruited. Firstly, the athletes performed an incremental running test for VO(2)max and anaerobic threshold (AT) determination, and were familiarized with the two shoe conditions (traditional training shoe (TTS) and GS, the latter containing a conductor element under the insole). One week apart, athletes performed running economy tests (20 min run at 80% of the AT) on a 400 m dirt track, with shoe conditions randomized. VO2, heart rate, lactate, and perceived fatigue were registered throughout the experiment. No differences in any of the physiological or perceptual variables were identified between shoe conditions, with an equal running economy in both TTS and GS (51.1 +/- 4.2 vs. 50.9 +/- 5.1 mL kg(-1) min(-1), respectively). Our results suggest that a grounding stimulus does not improve the energy cost of running, or the physiological/perceptual responses of elite athletes