Endocannabinoids and Heart Rate Variability Alterations after Exposure to Prolonged Intensive Physical Exercise of the Hellenic Navy SEALs

Background: Recent research indicates that both endocannabinoids (eCB) and heart rate variability (HRV) are associated with stress-induced experiences. However, these underlying mechanisms are not elucidated. The present study aims to investigate whether exposure to acute and chronic stress conditions can give rise to measurable changes, both to the peripheral eCB ligands and HRV. Methods: Thirteen candidates under intense preparation for their enlistment in the Hellenic Navy SEALs (HNS) participated in the study. All subjects underwent mental state examination, while HRV variables in time and frequency domain recordings were acquired. Furthermore, at baseline and 30 days after prolonged and intensive physical exercise, hair was collected to measure eCB ligands, such as anandamide (AEA), 2-arachidonoylglycerol (2-AG), and the N-acyl ethanolamine (NAE) molecules: palmitoylethanolamide (PEA) and oleoylethanolamide (OEA). Results: Comparing basal hair concentrations of eCB ligands before and after intense physical exercise, we found that AEA, PEA, and OEA were notably increased, whereas no differences were observed regarding the ligand 2-AG. Furthermore, there were observed associations between the concentrations of peripheral eCB ligands, both at baseline and after the prolonged physical exercise and the time and frequency domains of HRV. Conclusions: These findings suggest that endocannabinoid–HRV interrelations might share a short-term, and long-term adaptability of the changes in self-regulation associated with stress. Further studies will be required to determine the validity of peripheral eCB signaling and HRV as a biomarker for different aspects of the stress response.

Health-Risk Behavior-, Mental Health-, and Physical Exercise-Related Risk Factors for Tooth Fractures in Korean Adolescents

We aimed to determine factors related to tooth fracture experience in Korean adolescents. This study used data from the 14th Korea Youth Risk Behavior Survey in 2018, a cross-sectional web-based survey of health-risk behaviors among a representative sample of Korean middle- and high-school students aged 12–17 years. A total of 60,040 participants were selected using a complex sampling design of the survey from 400 middle schools and 400 high schools. They answered a self-administered questionnaire survey in classrooms. Explanatory variables included those pertaining to health-risk behaviors, mental health, and physical exercise. Complex-sample multivariable logistic regression models were applied to identify factors related to tooth fracture experience in the past 12 months. The overall prevalence of dental fracture experience was 11.4%. Risk factors related to tooth fractures in Korean adolescents were unhealthy behaviors such as alcohol and tobacco consumption; mental health problems including stress, depression, and suicidal ideation; and intensive physical exercise. The major risk factor related to tooth fractures was depression. To prevent tooth fractures among adolescents, schools should strengthen mental health education, encourage mouthguard use during intensive physical exercise, and develop school environments to prevent orofacial injuries. Further studies on various risk factors related to tooth fractures are warranted.

Effects of antioxidant supplementation on oxidative stress balance in young footballers: a randomized controlled trial

Background The intensive physical exercise in which athletes take part in competitive sports can negatively affect the pro-oxidative–antioxidant balance. The use of compounds with high antioxidant potential, which certainly should include chokeberry, can prevent these adverse changes. Methods The study was conducted on a group of football players aged 16–17 years, who underwent 7 weeks of supplementation with 200 ml chokeberry juice per day. Before and after supplementation, the participants performed an intensive physical exercise test (beep test). At rest, immediately after exercise and after 3 and 24 h of rest, venous blood was taken from the subjects, in which levels of thiobarbituric acid reactive products (TBARS), hydroxy-2'-deoxyguanosine (8-OHdG), total antioxidant capacity (TAC), iron (Fe), hepcidin, ferritin, myoglobin, albumin and morphological parameters were examined. Results There was a significant impact of the intervention in response to the physical exercise test in the studied groups on parameter dynamics: 8-OHdG (t = 3.56, p = 0.0005), albumin (t = 1.98, p = 0.049), TBARS (t = 4.33, p = 0.00003), hepcidin (t = 2.21, p = 0.03), and Mono level (t = 2.14, p = 0.04) and percentage (t = 2.27, p = 0.03). The post-hoc test showed no effect of chokeberry juice supply on any of the morphological, biochemical or performance parameters analysed. Conclusions The supplementation applied to footballers showed no effects under the influence of the applied exercise stress test. Such results may be the result of both the players’ adaptation to the applied exercise loads and the insufficient antioxidant capacity of the supplement used.

Tempe extract reduces cell damage in the liver and kidneys after intensive physical exercise in rats

Background and Aim: Cells of the liver and kidneys are perpetually exposed to free radicals from endogenous and exogenous sources. High-intensity physical exercise can induce oxidative stress. This study aimed to determine the effects of tempe extract on cell damage in the liver and kidneys of rats after intensive physical exercise. Materials and Methods: This study used five experimental groups: T0 (non-exercised control rats), T1 (rats made to exercise by swimming), and T2-T4 (rats made to exercise by swimming treated with 25, 50, and 100 mg/kg body weight tempe extract). The biochemical parameters that were analyzed included blood glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), blood urea nitrogen (BUN), and creatinine levels. The morphology of liver and kidney tissues was histopathologically and immunohistochemically analyzed. Results: Tempe extract treatment reduced cell damage in the liver and kidney tissues of rats, characterized by decreased expression of caspase-3. In addition, the ALT, AST, ALP, creatinine, and BUN levels of rats were significantly lower in tempe extract-treated rats than in rats after swimming exercise alone. Conclusion: Tempe extract is capable of reducing cell damage and apoptosis in the liver and kidney cells of rats after intensive physical exercise and maintaining biochemical properties similar to the normal physiological state.

Dark Chocolate Intake Positively Modulates Redox Status and Markers of Muscular Damage in Elite Football Athletes: A Randomized Controlled Study

Intensive physical exercise may cause increase oxidative stress and muscular injury in elite football athletes. The aim of this study was to exploit the effect of cocoa polyphenols on oxidative stress and muscular injuries induced by intensive physical exercise in elite football players. Oxidant/antioxidant status and markers of muscle damage were evaluated in 24 elite football players and 15 controls. Furthermore, the 24 elite football players were randomly assigned to either a dark chocolate (>85% cocoa) intake (n=12) or a control group (n=12) for 30 days in a randomized controlled trial. Oxidative stress, antioxidant status, and muscle damage were assessed at baseline and after 30 days of chocolate intake. Compared to controls, elite football players showed lower antioxidant power and higher oxidative stress paralleled by an increase in muscle damage markers. After 30 days of dark chocolate intake, an increased antioxidant power was found in elite athletes assuming dark chocolate. Moreover, a significant reduction in muscle damage markers (CK and LDH, p<0.001) was observed. In the control group, no changes were observed with the exception of an increase of sNox2-dp, H2O2, and myoglobin. A simple linear regression analysis showed that sNox2-dp was associated with a significant increase in muscle damage biomarker release (p=0.001). An in vitro study also confirmed that polyphenol extracts significantly decreased oxidative stress in murine myoblast cell line C2C12-derived. These results indicate that polyphenol-rich nutrient supplementation by means of dark chocolate positively modulates redox status and reduced exercise-induced muscular injury biomarkers in elite football athletes. This trial is registered with NCT03288623.

Changes in Echocardiographic Parameters among Beninese Soccer Referees during the Division 1 Championship in 2016

Introduction. The goal of this study was to describe the echocardiographic parameters of soccer referees and to examine the changes in these parameters after a period of intensive physical exercise. Methods and Patients. We conducted a prospective study that included Beninese soccer referees. The study of the geometry and function of the left ventricle (LV) was made at the beginning and end of the national Division 1 championship, which was held during the course of 10 weeks. Results. There were 37 referees included in this study; 20 at the national level (G1: 27.8 ± 6.6 years) and 17 at the international level (G2: 32.1 ± 6.4 years). Dimensions of the LV were normal for all the referees. At the beginning of the championship, 51.3% of the referees had a normal LV geometry, 37.8% had concentric remodelling, 2.7% had concentric hypertrophy, and 8.1% had eccentric hypertrophy. In the group of referees with normal LV geometry, a modification in concentric remodelling at the end of the championship was seen in 30% of the referees in G1, 33.3% of the referees in G2, and 31.6% of the whole sample. In the group of subjects who presented concentric LV remodelling, a modification in the normal geometry was observed in 37.5% of those in G1, in 0% of those in G2, and in 21.4% of the whole sample. The cases of LV hypertrophy showed no change regardless of the group considered. An LV ejection fraction of more than 50% and an E/E′ ratio less than 8 were found in all referees. Conclusion. All the referees studied had normal cardiac morphology and function. The intensity of the physical load was insufficient to impact this morphology.