Effect of Iron Supplementation on the Modulation of Iron Metabolism, Muscle Damage Biomarkers and Cortisol in Professional Cyclists

Background: The intense efforts made during 3-week stage races may reduce iron metabolism and hematological parameters. These efforts may increase the levels of circulating muscle damage markers and some hormones. All of these physiological changes may have negative consequences not only for the performance of athletes but also for their health. The main aim of this study was to evaluate the effects of supplementation with 80 mg/day of iron on haematological parameters, serum cortisol and biochemical muscle indicators on elite male cyclists during the 3-week stage race the Vuelta a España. Our secondary aim was to examine whether the hematological profile is associated with muscular damage parameters and cortisol. Methods: Eighteen elite male cyclists from two teams were randomly assigned to one of two groups: (1) control group (CG, n = 9; age: 26.1 ± 4.6 years; maximum oxygen uptake per kg: 78.0 ± 5.4 mL/kg/min) or (2) group treated with 80 mg/day iron (800 mg of iron protein succinylate, ITG, n = 9; age: 25.7 ± 6.4 years; maximum oxygen uptake per kg: 77.6 ± 6.5 mL/kg/min). The cyclists were subjected to blood tests one week before the start of the race (T1) and after 4 weeks of treatment, coinciding with the end of the competition (T2). Iron metabolism parameters, muscle damage indicators and serum cortisol were assessed. Repeated-measures ANOVA with group as a factor (GC and ITG) were used to examine the differences between groups throughout the study (time × group) after iron supplementation treatment. Results: Significant differences were observed between groups throughout the study in the group-by-time interaction and changes in serum iron (GC: -8.93 ± 10.35% vs. ITG: 0.60 ± 8.64%; p = 0.018), ferritin (GC: -13.88 ± 23.53% vs. ITG: 91.08 ± 118.30%; p = 0.004), haemoglobin (GC: 10.00 ± 3.32% vs. ITG: 13.04 ± 5.64%; p < 0.001), haematocrit (GC: -1.17 ± 3.78% vs. ITG: 7.32 ± 3.92%; p < 0.001) and cortisol (GC: 24.74 ± 25.84% vs. ITG: ⁻13.54 ± 13.61%; p = 0.005). However, no significant group-by-time interaction was observed for the circulating muscle biomarkers. Additionally, significant negative correlations of serum iron, haemoglobin and haematocrit with muscle circulating biomarkers and cortisol (p < 0.05) were observed. Conclusions: Oral iron supplementation with 80 mg/day iron (800 mg of iron protein succinylate) effectively prevented a decline in haematological parameters (serum iron, ferritin, haemoglobin and haematocrit) and maintained optimal levels of recovery in elite cyclists during the Vuelta a España. Moreover, the hematological values were shown to have relationship with muscular recovery parameters

The role of selenium mineral trace element in exercise: antioxidant defense system, muscle performance, hormone response, and athletic performance. A systematic review

Exercise overproduces oxygen reactive species (ROS) and eventually exceeds the body’s antioxidant capacity to neutralize them. The ROS produce damaging effects on the cell membrane and contribute to skeletal muscle damage. Selenium (Se), a natural mineral trace element, is an essential component of selenoproteins that plays an important role in antioxidant defense. The activity of the enzyme glutathione peroxidase (GPx), a highly-efficient antioxidant enzyme, is closely dependent on the presence of Se. These properties of Se may be potentially applicable to improve athletic performance and training recovery. We systematically searched for published studies to evaluate the effectiveness of Se supplementation on antioxidant defense system, muscle performance, hormone response, and athletic performance among physically active individuals. We used the Preferred Reporting Elements for Systematic Reviews and Meta-Analysis (PRISMA) guidelines and searched in SCOPUS, Web of Science (WOS), and PubMed databases to identify published studies until March 2020. The systematic review incorporated original studies with randomized controlled crossover or parallel design in which intake of Se administered once a day was compared with the same placebo conditions. No exclusions were applied for the type of physical exercise performed, the sex, nor the age of the participants. Among 150 articles identified in the search, 6 met the criteria and were included in the systematic review. The methodological quality of the studies was evaluated using the McMaster Critical Review Form. Oral Se supplementation with 180 µg/day or 240 µg/day (selenomethionine) and 200 µg/day (Sodium Selenite), significantly decreased lipid hydroperoxide levels and increased GPx in plasma, erythrocyte, and muscle. No significant effects were observed on athletic performance, testosterone hormone levels, creatine kinase activity, and exercise training-induced adaptations on oxidative enzyme activities or on muscle fiber type myosin heavy chain expression. In addition, Se supplementation showed to have a dampening effect on the mitochondria changes in chronic and acute exercise. In summary, the use of Se supplementation has no benefits on aerobic or anaerobic athletic performance but it may prevent Se deficiencies among athletes with high-intensity and high-volume training. Optimal Se plasma levels may be important to minimize chronic exercise-induced oxidative effects and modulate the exercise effect on mitochondrial changes

Electromyography: a simple and accessible tool to assess physical performance and health during hypoxia training. A systematic review

Hypoxia causes reduced partial pressure of oxygen in arterial blood and induces adaptations in skeletal muscle that may affect individuals’ physical performance and muscular health. These muscular changes are detectable and quantifiable by electromyography (EMG), an instrument that assesses electrical activity during active contraction at rest. EMG is a relatively simple and accessible technique for all patients, one that can show the degree of the sensory and motor functions because it provides information about the status of the peripheral nerves and muscles. The main goal of this review is to evaluate the scientific evidence of EMG as an instrument for monitoring different responses of skeletal muscles subjected to external stimuli such as hypoxia and physical activity. A structured search was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines in Medline/PubMed, Scielo, Google Scholar, Web of Science, and Cochrane Library Plus. The search included articles published in the last 25 years until May 2020 and was restricted to English- and Spanish-language publications. As such, investigators identified nine articles that met the search criteria. The results determined that EMG was able to detect muscle fatigue from changes in the frequency spectrum. When a muscle was fatigued, high frequency components decreased and low frequency components increased. In other studies, EMG determined muscle activation increased during exercise by recruiting motor units and by increasing the intensity of muscle contractions. Finally, it was also possible to calculate the mean quadriceps quadratic activity used to obtain an image of muscle activation. In conclusion, EMG offers a suitable tool for monitoring the different skeletal muscle responses and has sufficient sensitivity to detect hypoxia-induced muscle changes produced by hypoxic stimuli. Moreover, EMG enhances an extension of physical examination and tests motor-system integrity

Risk for cardiovascular disease associated with metabolic syndrome and its components: a 13-year prospective study in the RIVANA cohort

Background We aimed to investigate the association of metabolic syndrome (MetS) and its single components with cardiovascular risk and estimated their impact on the prematurity of occurrence of cardiovascular events using rate advancement periods (RAPs). Methods We performed prospective analyses among 3976 participants (age range: 35–84, 55% female) in the Vascular Risk in Navarre (RIVANA) Study, a Mediterranean population-based cohort. MetS was defined based on the modified criteria of the American Heart Association/National Heart, Lung, and Blood Institute and the International Diabetes Federation. The primary endpoint was major cardiovascular event (a composite of myocardial infarction, stroke, or mortality from cardiovascular causes). Secondary endpoints were incidence of non-fatal myocardial infarction and non-fatal stroke, cardiovascular mortality, and all-cause mortality. Cox proportional hazards models, adjusted for potential confounders, were fitted to evaluate the association between MetS and its single components at baseline with primary and secondary endpoints. Results During a median follow-up of 12.8 years (interquartile range, 12.5–13.1), we identified 228 primary endpoint events. MetS was associated with higher risk of incidence of major cardiovascular event, cardiovascular and all-cause mortality, but was neither associated with higher risk of myocardial infarction nor stroke. Compared with participants without MetS, the multivariable hazard ratio (95% confidence interval [CI]) among participants with MetS was 1.32 (1.01–1.74) with RAP (95% CI) of 3.23 years (0.03, 6.42) for major cardiovascular event, 1.64 (1.03–2.60) with RAP of 3.73 years (0.02, 7.45) for cardiovascular mortality, and 1.45 (1.17–1.80) with RAP of 3.24 years (1.21, 5.27) for all-cause mortality. The magnitude of the associations of the single components of MetS was similar than the predicted by MetS. Additionally, for each additional trait of MetS, incidence of major cardiovascular event relatively increased by 22% (1.22, 95% CI 1.09–1.36) with RAP of 2.31 years (0.88, 3.74). Conclusions MetS was independently associated with CVD risk, cardiovascular and all-cause mortality. Components of the MetS were associated with similar magnitude of increased CVD, which suggests that MetS was not in excess of the level explained by the presence of its single components. Further research should explore the association of different combinations of the components of MetS with CVD

Adherence to treatment and related factors among patients with chronic conditions in primary care: a cross-sectional study

Background: Adherence to treatment, a public health issue, is of particular importance in chronic disease therapies. Primary care practices offer ideal venues for the effective care and management of these conditions. The aim of this study is to assess adherence to treatment and related-factors among patients with chronic conditions in primary care settings. Methods: A cross-sectional study was conducted among 299 adult patients with ≥1 chronic condition(s) and prescribed medication in primary healthcare centers of Spain. The Morisky-Green-Levine questionnaire was used to assess medication adherence via face-to-face interviews. Crude and adjusted multivariable logistic regression models were used to analyze factors associated with adherence using the Multidimensional Model proposed by the World Health Organization — social and economic, healthcare team and system-related, condition-related, therapy-related, and patient-related factors. Results: The proportion of adherent patients to treatment was 55.5%. Older age (adjusted odds ratio 1.31 per 10- year increment, 95% CI 1.01–1.70), lower number of pharmacies used for medication refills (0.65, 95% CI 0.47– 0.90), having received complete treatment information (3.89, 95% CI 2.09–7.21), having adequate knowledge about medication regimen (4.17, 95% CI 2.23–7.80), and self-perception of a good quality of life (2.17, 95% CI 1.18–4.02) were independent factors associated with adherence. Conclusions: Adherence to treatment for chronic conditions remained low in primary care. Optimal achievement of appropriate levels of adherence through tailored multifaceted interventions will require attention to the multidimensional factors found in this study, particularly those related to patients’ education and their information needs

Leisure-time physical activity, sedentary behavior, and risk of breast cancer: Results from the SUN (‘Seguimiento Universidad De Navarra’) project

Evidence is still limited on the influence of sedentary lifestyles on breast cancer (BC) risk. Also, prospective information on the combined effects of both sedentariness and leisure-time physical activity (LTPA) is scarce. We aimed to assess the association of higher sedentary behavior and LTPA (separately and in combination) with the risk of BC in a middle-aged cohort of university graduates. The SUN Project is a follow-up study initiated in 1999 with recruitment permanently open. Baseline assessments included a validated questionnaire on LTPA and sedentary habits. Subsequently, participants completed biennial follow-up questionnaires. Multivariable adjusted Cox models were used to estimate the hazard ratios (HR) for incident BC according to LTPA, TV-watching, the joint classification of both, and a combined 8-item multidimensional active lifestyle score. We included 10,812 women, with 11.8 years of median follow-up of. Among 115,802 women-years of follow-up, we confirmed 101 incident cases of BC. Women in the highest category of LTPA (>16.5 MET-h/week) showed a significantly lower risk of BC (HR = 0.55; 95% CI: 0.34–0.90) compared to women in the lowest category (≤6 MET/h-week). Women watching >2 h/d of TV sh owed a higher risk (HR = 1.67; 95% CI:1.03–2.72) than those who watched TV 2 h/d may substantially increase BC risk, independently of each other

The role of selenium mineral trace element in exercise: antioxidant defense system, muscle performance, hormone response, and athletic performance. A systematic review

Exercise overproduces oxygen reactive species (ROS) and eventually exceeds the body’s antioxidant capacity to neutralize them. The ROS produce damaging effects on the cell membrane and contribute to skeletal muscle damage. Selenium (Se), a natural mineral trace element, is an essential component of selenoproteins that plays an important role in antioxidant defense. The activity of the enzyme glutathione peroxidase (GPx), a highly-efficient antioxidant enzyme, is closely dependent on the presence of Se. These properties of Se may be potentially applicable to improve athletic performance and training recovery. We systematically searched for published studies to evaluate the effectiveness of Se supplementation on antioxidant defense system, muscle performance, hormone response, and athletic performance among physically active individuals. We used the Preferred Reporting Elements for Systematic Reviews and Meta-Analysis (PRISMA) guidelines and searched in SCOPUS, Web of Science (WOS), and PubMed databases to identify published studies until March 2020. The systematic review incorporated original studies with randomized controlled crossover or parallel design in which intake of Se administered once a day was compared with the same placebo conditions. No exclusions were applied for the type of physical exercise performed, the sex, nor the age of the participants. Among 150 articles identified in the search, 6 met the criteria and were included in the systematic review. The methodological quality of the studies was evaluated using the McMaster Critical Review Form. Oral Se supplementation with 180 µg/day or 240 µg/day (selenomethionine) and 200 µg/day (Sodium Selenite), significantly decreased lipid hydroperoxide levels and increased GPx in plasma, erythrocyte, and muscle. No significant effects were observed on athletic performance, testosterone hormone levels, creatine kinase activity, and exercise training-induced adaptations on oxidative enzyme activities or on muscle fiber type myosin heavy chain expression. In addition, Se supplementation showed to have a dampening effect on the mitochondria changes in chronic and acute exercise. In summary, the use of Se supplementation has no benefits on aerobic or anaerobic athletic performance but it may prevent Se deficiencies among athletes with high-intensity and high-volume training. Optimal Se plasma levels may be important to minimize chronic exercise-induced oxidative effects and modulate the exercise effect on mitochondrial changes

Electromyography: a simple and accessible tool to assess physical performance and health during hypoxia training. A systematic review

Hypoxia causes reduced partial pressure of oxygen in arterial blood and induces adaptations in skeletal muscle that may affect individuals’ physical performance and muscular health. These muscular changes are detectable and quantifiable by electromyography (EMG), an instrument that assesses electrical activity during active contraction at rest. EMG is a relatively simple and accessible technique for all patients, one that can show the degree of the sensory and motor functions because it provides information about the status of the peripheral nerves and muscles. The main goal of this review is to evaluate the scientific evidence of EMG as an instrument for monitoring different responses of skeletal muscles subjected to external stimuli such as hypoxia and physical activity. A structured search was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines in Medline/PubMed, Scielo, Google Scholar, Web of Science, and Cochrane Library Plus. The search included articles published in the last 25 years until May 2020 and was restricted to English- and Spanish-language publications. As such, investigators identified nine articles that met the search criteria. The results determined that EMG was able to detect muscle fatigue from changes in the frequency spectrum. When a muscle was fatigued, high frequency components decreased and low frequency components increased. In other studies, EMG determined muscle activation increased during exercise by recruiting motor units and by increasing the intensity of muscle contractions. Finally, it was also possible to calculate the mean quadriceps quadratic activity used to obtain an image of muscle activation. In conclusion, EMG offers a suitable tool for monitoring the different skeletal muscle responses and has sufficient sensitivity to detect hypoxia-induced muscle changes produced by hypoxic stimuli. Moreover, EMG enhances an extension of physical examination and tests motor-system integrity

Risk for cardiovascular disease associated with metabolic syndrome and its components: a 13-year prospective study in the RIVANA cohort

Background We aimed to investigate the association of metabolic syndrome (MetS) and its single components with cardiovascular risk and estimated their impact on the prematurity of occurrence of cardiovascular events using rate advancement periods (RAPs). Methods We performed prospective analyses among 3976 participants (age range: 35–84, 55% female) in the Vascular Risk in Navarre (RIVANA) Study, a Mediterranean population-based cohort. MetS was defined based on the modified criteria of the American Heart Association/National Heart, Lung, and Blood Institute and the International Diabetes Federation. The primary endpoint was major cardiovascular event (a composite of myocardial infarction, stroke, or mortality from cardiovascular causes). Secondary endpoints were incidence of non-fatal myocardial infarction and non-fatal stroke, cardiovascular mortality, and all-cause mortality. Cox proportional hazards models, adjusted for potential confounders, were fitted to evaluate the association between MetS and its single components at baseline with primary and secondary endpoints. Results During a median follow-up of 12.8 years (interquartile range, 12.5–13.1), we identified 228 primary endpoint events. MetS was associated with higher risk of incidence of major cardiovascular event, cardiovascular and all-cause mortality, but was neither associated with higher risk of myocardial infarction nor stroke. Compared with participants without MetS, the multivariable hazard ratio (95% confidence interval [CI]) among participants with MetS was 1.32 (1.01–1.74) with RAP (95% CI) of 3.23 years (0.03, 6.42) for major cardiovascular event, 1.64 (1.03–2.60) with RAP of 3.73 years (0.02, 7.45) for cardiovascular mortality, and 1.45 (1.17–1.80) with RAP of 3.24 years (1.21, 5.27) for all-cause mortality. The magnitude of the associations of the single components of MetS was similar than the predicted by MetS. Additionally, for each additional trait of MetS, incidence of major cardiovascular event relatively increased by 22% (1.22, 95% CI 1.09–1.36) with RAP of 2.31 years (0.88, 3.74). Conclusions MetS was independently associated with CVD risk, cardiovascular and all-cause mortality. Components of the MetS were associated with similar magnitude of increased CVD, which suggests that MetS was not in excess of the level explained by the presence of its single components. Further research should explore the association of different combinations of the components of MetS with CVD

Pregestational BMI and higher offspring’s risk of overweight/obesity in smoker and non-smoker mothers

Objective: To assess the association between pregestational BMI and offspring's risk of overweight/obesity after accounting for the most important confounders, especially maternal smoking habit. Design: Prospective cohort study. Setting: The Seguimiento Universidad de Navarra (SUN) study is a prospective cohort of Spanish graduates with more than 22 000 participants nationwide. Recruitment started in 1999, and it is permanently open. Data on diet, lifestyle and clinical diagnoses are collected at baseline and every 2 years. Participants: Women from the SUN cohort who reported at least one pregnancy during follow-up (n 3496) were invited to this study. Among them, 1527 agreed to participate and completed an additional more detailed online questionnaire on their pregnancy history and their offspring's nutritional status. Results: After excluding 165 children, we analysed data of 2791 participants born to 1485 mothers and observed that each 5 kg/m2 increase in pregestational BMI was associated with a 0·22 (95 % CI 0·15, 0·29) higher z-score in offspring's BMI and higher risk of overweight/obesity (multivariable-adjusted relative risk (RR) 1·57 (95 % CI 1·39, 1·77)) in childhood or adolescence. Furthermore, we observed stronger association in children born to smoker mothers (RR 1·91; 95 % CI 1·48, 2·46) than from non-smoker mothers (RR 1·51; 95 % CI 1·31, 1·73) (Pfor interaction = 0·02). Conclusions: We found a synergistic interaction between pregestational BMI and maternal smoking habit on offspring's z-score of the BMI and in their risk of overweight/obesity. Although further research is needed to analyse dose-response relationships, these findings reinforce the importance of promoting healthy lifestyles in pregnant women in order to prevent childhood obesity