Consistent changes in muscle phenotype and mitochondrial abundance underlie dive performance across multiple lineages of diving ducks.

Diving animals must sustain high muscle activity with finite oxygen (O2) to forage underwater. Studies have shown that some diving mammals exhibit changes in the metabolic phenotype of locomotory muscles compared to non-divers, but the pervasiveness of such changes across diving animals is unclear, particularly among diving birds. Here, we examine whether changes in muscle phenotype and mitochondrial abundance are associated with dive capacity across 17 species of ducks from three distinct evolutionary clades (tribes) in the subfamily Anatinae - the longest diving sea ducks, the mid-tier diving pochards, and the non-diving dabblers. In the gastrocnemius (the primary swimming and diving muscle), mitochondrial volume density in both oxidative and glycolytic fiber types were 70% and 30% higher in sea ducks compared to dabblers, respectively. These differences were associated with preferential proliferation of the subsarcolemmal subfraction, the mitochondria adjacent to the cell membrane and nearest to capillaries, relative to the intermyofibrillar subfraction. Capillary density and capillary-to-fiber ratio were positively correlated with mitochondrial volume density, with no variation in the density of oxidative fiber types across tribes. In the pectoralis, sea ducks had greater abundance of oxidative fiber types than dabblers, whereas pochards were intermediate between the two. These data suggest that skeletal muscles of sea ducks have a heightened capacity for aerobic metabolism and an enhanced ability to utilize O2 stores in the blood and muscle while diving.

Auditing the representation of hormonal contraceptives in studies assessing exercise performance in women.

Hormonal contraceptive (HC) users have a different ovarian hormonal profile compared to eumenorrheic women. Due to the prevalence of HC use amongst sportswomen, there has been increased research efforts to understand their impact on exercise performance. The aim was to audit this research. Studies identified were assessed for HC type, athlete calibre, performance outcome, study design, and quality of methodological control regarding ovarian hormonal profiles. Sixty-eight different HCs were reported across 61 studies. Monophasic combined oral contraceptive (OCP) pills represented 60% of HCs, followed by other pills [34%, phasic-combined, progestogen-only, and un-specified], phasic and long acting reversible contraceptives [5%, vaginal ring, patch, implant, injection, intrauterine system] and unspecified HCs (1%). Eleven percent of participants using HCs were classified as highly trained or elite/international with no participants being classed as world class. Whilst the number of studies involving HCs has increased two-fold over the past decade, the number of studies ranked as gold standard has not increased (HC; 2003-57%, 2011-55%, 2022-43%. OCP; 2003-14%, 2011-17%, 2022-12%). Future research assessing HCs and exercise performance should adopt high-quality research designs and include a broader range of HCs in highly trained to world-class populations to increase the reach and impact of research in this area.

6-week time-restricted eating improves body composition, maintains exercise performance, without exacerbating eating disorder in female DanceSport dancers.

BACKGROUND: Despite the high risk of eating disorder (ED)-related attitudes and behaviors among female dancers, targeted scientific dietary regimens are currently inadequate. Time-restricted eating (TRE), a popular intermittent fasting protocol, has been shown to be effective in enhancing body composition and exercise performance in athletes. In this study, TRE was employed as a dietary regimen to improve body composition and exercise performance and address ED attitudes and behaviors in DanceSport dancers. METHODS: Twenty female DanceSport dancers were recruited and divided into two groups: TRE (n = 10) and normal diet (ND) (n = 10). The TRE group consumed their self-selected necessary energy intake exclusively between 11 a.m. and 7 p.m. (utilizing a 16-hour fasting and 8-hour eating window) for 6 weeks, while the ND group maintained their regular dieting patterns. The consumption of water, black tea, or coffee without added sugar or milk was not restricted. Physical activity and calorie intake were systematically recorded during the TRE intervention. Body composition, aerobic and anaerobic performance, and ED attitudes and behaviors were assessed before and after the TRE intervention. The trial was registered in the Chinese Clinical Trial Registry under the identifier ChiCTR2200063780. RESULTS: The fixed effects tests (p < 0.0001) and estimates for the intercept (p < 0.0001) of hunger level indicated a noticeable effect on the initial state of hunger during TRE. No significant differences were observed in ED attitudes or behaviors (p > 0.05). TRE resulted in a reduction in hip circumference (p = 0.039), fat mass (kg) (p = 0.0004), and body fat percentage (p = 0.0005), with no significant decrease in fat-free mass (p > 0.05). No significant improvement was observed in aerobic performance (p > 0.05). The average power (AP) (p = 0.01) and AP/Body weight ratio (p = 0.003) significantly increased. Additionally, the power drop decreased significantly (p = 0.019). Group-by-time interactions were observed for fat mass (kg) (p = 0.01), body fat percentage (p = 0.035), and AP/Body weight (p = 0.020). CONCLUSION: TRE can be considered a feasible nutritional strategy for DanceSport dancers, facilitating improvements in body composition without compromising aerobic and anaerobic exercise performance or exacerbating ED attitudes and behaviors. Moreover, TRE may facilitate more favorable physiological adaptations, potentially contributing to improved exercise performance.

The effects of high-intensity interval training versus moderate-intensity continuous training on athletes' aerobic endurance performance parameters.

OBJECTIVE: To systematically evaluate and meta-analyze the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on athletes of aerobic endurance performance parameters. METHODS: PubMed, Web of Science, EBSCO, Embase, and Cochrane databases were searched. The assessment of quality was conducted employing The Cochrane Risk of Bias Assessment Tool, while heterogeneity examination and subgroup analysis were performed. Moreover, regression and sensitivity analyses were executed. RESULTS: There was no significant difference between the effects of HIIT and MICT on the enhancement of athletes' running economy (RE) (P > 0.05); 1-3 weeks and 4-9 weeks of HIIT were more effective in improving athletes' maximum oxygen uptake (VO2max) (P < 0.05), and 10 weeks and above were not significant (P > 0.05); 1-3 weeks of HIIT was more effective in improving athletes' anaerobic threshold (AT) (P < 0.05), and 4-10 weeks was not significant (P > 0.05); 3 weeks of high-intensity interval training (HIIT) did not significantly enhance athletes' minute ventilation (VE) (P > 0.05), whereas a duration of 6-10 weeks yielded superior results (P < 0.05); 8 weeks of moderate-intensity continuous training (MICT) did not significantly enhance athletes' hemoglobin (Hb) level (P > 0.05), whereas a duration of 2-3 weeks yielded superior results (P < 0.05). CONCLUSIONS: (1) HIIT and MICT have similar effects on enhancing athletes' RE. (2) 6-9 weeks' HIIT was more effective in improving athletes' VO2max and VE, and 3 weeks' HIIT was more effective in improving athletes' AT. (3) Within 3 weeks, MICT was more effective in improving the Hb level of athletes. REGISTRATION NUMBER ON PROSPERO: CRD42024499039.

Effects of exercise on sex steroid hormones (estrogen, progesterone, testosterone) in eumenorrheic females: A systematic to review and meta-analysis.

BACKGROUND: The sex steroid hormones fluctuate during the menstrual cycle, which affects the strength and postural stability of females and leads to injuries and risk of falls. These hormones may be modulated by exercise to impact the overall health of females. OBJECTIVE: To determine the effects of exercise on sex steroid hormones in eumenorrheic females. METHODS: This review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA) guidelines in Lahore, Pakistan. The full-length articles were searched using these databases/search engines (PubMed, Web of Science and Google Scholar, Sci-Hub). Randomized controlled trials along with single group experimental studies were also included. All types of exercises were compared with no exercise in the control group. The Cochrane Risk of Bias assessment tool assessed and screened the articles. The data were then analyzed. The primary outcomes were the levels of estrogen, progesterone and testosterone. RESULTS: Eleven studies were included (5 randomized controlled trials and 6 quasi-experimental studies). The effects of exercise on free estradiol concentration and serum progesterone level were not significant [p = 0.37 (SMD = 0.33, 95% CI = 0.14 to 0.74, I2 = 0%) and p = 0.84 (S.D= -0.65, C.I= -6.92 to 5.62, I2 = 94%)] respectively, whereas, the effects on testosterone levels were significant [p value < 0.00001 (M.D = 0.89, 95% C.I= -2.16 to 3.95, I2 = 94%)]. CONCLUSION: A blinded randomized controlled trial should be conducted in which a structured approach should be followed by women along with warm-ups, cool down and rest intervals. TRIAL REGISTRATION NUMBER: The systematic review was registered prospectively on PROSPERO with registration number CRD42023473767.

Low energy availability increases immune cell formation of reactive oxygen species and impairs exercise performance in female endurance athletes.

INTRODUCTION: The effects of low energy availability (LEA) on the immune system are poorly understood. This study examined the effects of 14 days of LEA on immune cell redox balance and inflammation at rest and in response to acute exercise, and exercise performance in female athletes. METHODS: Twelve female endurance athletes (age: 26.8 ± 3.4 yrs, maximum oxygen uptake (V˙O2max): 55.2 ± 5.1 mL × min-1 × kg-1) were included in a randomized, single-blinded crossover study. They were allocated to begin with either 14 days of optimal energy availability diet (OEA, 52 ± 2 kcal × kg fat free mass (FFM)-1 × day-1) or LEA diet (22 ± 2 kcal × kg FFM-1 × day-1), followed by 3 days of refueling (OEA) with maintained training volume. Peripheral blood mononuclear cells (PBMCs) were isolated, and plasma obtained at rest before and after each dietary period. The PBMCs were used for analysis of mitochondrial respiration and H2O2 emission and specific proteins. Exercise performance was assessed on cycle by a 20-min time trial and time to exhaustion at an intensity corresponding to ∼110 % V˙O2max). RESULTS: LEA was associated with a 94 % (P = 0.003) increase in PBMC NADPH oxidase 2 protein content, and a 22 % (P = 0.013) increase in systemic cortisol. LEA also caused an alteration of several inflammatory related proteins (P < 0.05). Acute exercise augmented H2O2 emission in PBMCs (P < 0.001) following both OEA and LEA, but to a greater extent following LEA. LEA also reduced the mobilization of white blood cells with acute exercise. After LEA, performance was reduced in both exercise tests (P < 0.001), and the reduced time trial performance remained after the 3 days of refueling (P < 0.001). CONCLUSION: 14 days of LEA in female athletes increased cortisol levels and had a pronounced effect on the immune system, including increased capacity for ROS production, altered plasma inflammatory proteome and lowered exercise induced mobilization of leukocytes. Furthermore, LEA resulted in a sustained impairment in exercise performance.

The Relationship between Inspiratory Muscle Strength and Cycling Performance: Insights from Hypoxia and Inspiratory Muscle Warm-Up.

Hypoxia increases inspiratory muscle work and consequently contributes to a reduction in exercise performance. We evaluate the effects of inspiratory muscle warm-up (IMW) on a 10 km cycling time trial in normoxia (NOR) and hypoxia (HYP). Eight cyclists performed four time trial sessions, two in HYP (FiO2: 0.145) and two in NOR (FiO2: 0.209), of which one was with IMW (set at 40% of maximal inspiratory pressure-MIP) and the other was with the placebo effect (PLA: set at 15% MIP). Time trials were unchanged by IMW (NORIMW: 893.8 ± 31.5 vs. NORPLA: 925.5 ± 51.0 s; HYPIMW: 976.8 ± 34.2 vs. HYPPLA: 1008.3 ± 56.0 s; p > 0.05), while ventilation was higher in HYPIMW (107.7 ± 18.3) than HYPPLA (100.1 ± 18.9 L.min-1; p ≤ 0.05), and SpO2 was lower (HYPIMW: 73 ± 6 vs. HYPPLA: 76 ± 6%; p ≤ 0.05). A post-exercise-induced reduction in inspiratory strength was correlated with exercise elapsed time during IMW sessions (HYPIMW: r = -0.79; p ≤ 0.05; NORIMW: r = -0.70; p ≤ 0.05). IMW did not improve the 10 km time trial performance under normoxia and hypoxia.

Nutritional knowledge, eating habits, factors affecting muscle damage, and antioxidant enzyme levels of Korean wrestlers.

PURPOSE: The aim in this study was to investigate the diet and nutritional knowledge of elite Korean wrestlers and verify the differences in their exercise performance , muscle damage indicators, and antioxidant enzyme levels according to wrestler level. METHODS: A 7-day dietary and nutrition knowledge survey was administered to 30 adult male elite wrestlers (national team: n=11; professional team: n=19). The Wingate test was conducted for 60 seconds to analyze muscle damage indicators and antioxidant levels. Blood and blood lactate concentration analyses were performed four times; the statistical significance level of all data was p<0.05. RESULTS: Significant differences were found in general nutrition knowledge questionnaire (GNKQ) scores (p=0.043), diet (p=0.001), anaerobic performance (p=0.001), muscle damage indicators (p=0.026), antioxidant levels, and blood lactic acid concentrations (30 min after exercise, p=0.007; 90 min after exercise, p=0.038) between the national and the professional groups. CONCLUSION: To the findings confirm the relationship between the differences in diet, nutrition, and motor function for wrestlers of different expertise levels. In a follow-up, a comprehensive study on nutrition knowledge, athlete training , and weight loss is needed that considers a wider scope of subjects and analyzes additional variables.

Caffeinated Chewing Gum Improves Basketball Shooting Accuracy and Physical Performance Indicators of Trained Basketball Players: A Double-Blind Crossover Trial.

(1) Background: This study investigated the effects of caffeinated chewing gum on the basketball-specific performance of trained basketball players. A double-blind, randomized crossover design was employed. (2) Methods: Fifteen participants (age: 20.9 ± 1.0 years; height: 180.9 ± 5.4 cm; mass: 77.2 ± 7.5 kg; training age: 8.2 ± 0.3 years) were recruited and divided into a caffeine trial (CAF) and placebo trial (PL). The participants in the CAF trial chewed gum containing 3 mg/kg of caffeine for 10 min, while those in the PL trial chewed a placebo gum without caffeine. Following a 15 min rest, all the participants completed basketball-specific performance tests. (3) Results: The free throw accuracy for the CAF trial was significantly higher than that for the PL trial (CAF: 79.0 ± 4.31%; PL: 73.0 ± 9.16%; p = 0.012; Cohen's d = 0.94). Additionally, the CAF trial demonstrated significantly better performance in the 20 m segmented dash (CAF: 2.94 ± 1.12 s; PL: 3.13 ± 0.10 s; p < 0.001; Cohen's d =1.8) and squats (p < 0.05), and exhibited lower fatigue indexes (CAF: 3.6 ± 1.6%; PL: 5.2 ± 1.6%; p = 0.009; Cohen's d =1.0). (4) Conclusions: These findings suggest that chewing gum containing 3 mg/kg of caffeine offers moderate-to-large improvements in key performance aspects relevant to professionally trained basketball players.

Heat acclimation improves exercise performance in hot conditions and increases heat shock protein 70 and 90 of skeletal muscles in Thoroughbred horses.

This study aimed to determine whether heat acclimation could induce adaptations in exercise performance, thermoregulation, and the expression of proteins associated with heat stress in the skeletal muscles of Thoroughbreds. Thirteen trained Thoroughbreds performed 3 weeks of training protocols, consisting of cantering at 90% maximal oxygen consumption (VO2max) for 2 min 2 days/week and cantering at 7 m/s for 3 min 1 day/week, followed by a 20-min walk in either a control group (CON; Wet Bulb Globe Temperature [WBGT] 12-13°C; n = 6) or a heat acclimation group (HA; WBGT 29-30°C; n = 7). Before and after heat acclimation, standardized exercise tests (SET) were conducted, cantering at 7 m/s for 90 s and at 115% VO2max until fatigue in hot conditions. Increases in run time (p = 0.0301), peak cardiac output (p = 0.0248), and peak stroke volume (p = 0.0113) were greater in HA than in CON. Pulmonary artery temperature at 7 m/s was lower in HA than in CON (p = 0.0332). The expression of heat shock protein 70 (p = 0.0201) and 90 (p = 0.0167) increased in HA, but not in CON. These results suggest that heat acclimation elicits improvements in exercise performance and thermoregulation under hot conditions, with a protective adaptation to heat stress in equine skeletal muscles.

Effects of probiotic supplementation on 12 min run performance, mood management, body composition and gut microbiota in amateur marathon runners: A double-blind controlled trial.

Background: Probiotic supplementation has a positive effect on endurance exercise performance and body composition in athletes, but the underlying mechanisms remain unclear. Gut microbiota can provide measurable markers of immune function in athletes, and microbial composition analysis may be sensitive enough to detect stress and metabolic disorders caused by exercise. Methods: Nineteen healthy active amateur marathon runners (15 male and 4 female) with a mean age of 29.11 years volunteered to participate in this double-blind controlled study. Based on the performance of the Cooper 12-min running test (CRT), the participants were allocated into two groups to receive either a probiotic formulation comprising lactobacillus acidophilus and bifidobacterium longum (n = 10) or placebo containing maltodextrin (n = 9) for five weeks. Consistency of diet and exercise was ensured throughout the experimental period. Before and after the intervention, all participants were assessed for CRT, emotional stability and gastrointestinal symptoms, gut microbiota composition, body composition and magnetic resonance imaging (MRI) indicators of skeletal muscle microcirculation. Results: Compared to before the intervention, the probiotics group showed an increase in CRT score (2.88 ± 0.57 vs 3.01 ± 0.60 km, P＜0.05), significant improvement in GSRS and GIQLI (9.20 ± 4.64 vs 7.40 ± 3.24, 118.90 ± 12.30 vs 127.50 ± 9.85, P＜0.05), while these indicators remained unchanged in the control group, with a significant time-group interaction effect on gastrointestinal symptoms. Additionally, some MRI metabolic cycling indicators of the thigh skeletal muscle also changed in the probiotics group (P＜0.05). Regarding microbiota abundance, the probiotics group exhibited a significant increase in the abundance of beneficial bacteria and a significant decrease in the abundance of harmful bacteria post-intervention (P＜0.05). Conclusion: As a sports nutritional supplement, probiotics have the potential to improve athletic performance by optimizing the balance of gut microbiota, alleviating gastrointestinal symptoms.

Corrigendum: Fat oxidation rates and cardiorespiratory responses during exercise in different subject populations with post-acute sequelae of SARS-CoV-2 infection: a comparison with normative percentile values.

[This corrects the article DOI: 10.3389/fphys.2023.1310319.].

Exploring the Impact of Alternative Sources of Dietary Nitrate Supplementation on Exercise Performance.

An increase in the level of nitric oxide (NO) plays a key role in regulating the human cardiovascular system (lowering blood pressure, improving blood flow), glycemic control in type 2 diabetes, and may help enhance exercise capacity in healthy individuals (including athletes). This molecule is formed by endogenous enzymatic synthesis and the intake of inorganic nitrate (NO3-) from dietary sources. Although one of the most well-known natural sources of NO3- in the daily diet is beetroot (Beta vulgaris), this review also explores other plant sources of NO3- with comparable concentrations that could serve as ergogenic aids, supporting exercise performance or recovery in healthy individuals. The results of the analysis demonstrate that red spinach (Amaranthus spp.) and green spinach (Spinacia oleracea) are alternative natural sources rich in dietary NO3-. The outcomes of the collected studies showed that consumption of selected alternative sources of inorganic NO3- could support physical condition. Red spinach and green spinach have been shown to improve exercise performance or accelerate recovery after physical exertion in healthy subjects (including athletes).

Kaempferol Improves Exercise Performance by Regulating Glucose Uptake, Mitochondrial Biogenesis, and Protein Synthesis via PI3K/AKT and MAPK Signaling Pathways.

Kaempferol is a natural flavonoid with reported bioactivities found in many fruits, vegetables, and medicinal herbs. However, its effects on exercise performance and muscle metabolism remain inconclusive. The present study investigated kaempferol's effects on improving exercise performance and potential mechanisms in vivo and in vitro. The grip strength, exhaustive running time, and distance of mice were increased in the high-dose kaempferol group (p < 0.01). Also, kaempferol reduced fatigue-related biochemical markers and increased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) related to antioxidant capacity. Kaempferol also increased the glycogen and adenosine triphosphate (ATP) content in the liver and skeletal muscle, as well as glucose in the blood. In vitro, kaempferol promoted glucose uptake, protein synthesis, and mitochondrial function and decreased oxidative stress in both 2D and 3D C2C12 myotube cultures. Moreover, kaempferol activated the PI3K/AKT and MAPK signaling pathways in the C2C12 cells. It also upregulated the key targets of glucose uptake, mitochondrial function, and protein synthesis. These findings suggest that kaempferol improves exercise performance and alleviates physical fatigue by increasing glucose uptake, mitochondrial biogenesis, and protein synthesis and by decreasing ROS. Kaempferol's molecular mechanism may be related to the regulation of the PI3K/AKT and MAPK signaling pathways.

Effects of a pulmonary rehabilitation program on pulmonary function, exercise performance, and quality of life in patients with severe COVID-19.

BACKGROUND: Severe coronavirus 2019 disease (COVID-19) causes acute hypoxemic respiratory failure requiring invasive mechanical ventilation (IMV). Once these symptoms are resolved, patients can present systemic deterioration. OBJECTIVE: The two objectives of this study were as follows: to describe the results of a pulmonary rehabilitation program (PRP), which is divided into three groups with different numbers of sessions (12, 24, and 36), and to associate the variables of pulmonary function, exercise performance, and functionality with the number of sessions and functional improvement. DESIGN: Prospective, observational study. METHODS: PRP consisted of aerobic + strength + flexibility exercises under the supervision and individualized into 12, 24, or 36 sessions (12s, 24s, and 36s), depending on the evolution of each patient. At the beginning of the study and immediately after the intervention, forced vital capacity (FVC), maximal inspiratory pressure, 6-minute walk test (6MWT), sit-to-stand test (STS), maximal handgrip strength (HGS), Fatigue Assessment Scale, Post-COVID-19 Functional Status (PCFS), and health-related quality of life (HRQoL) were measured. RESULTS: The proposed PRP demonstrated a positive effect on pulmonary function, exercise performance, and HRQoL, regardless of the number of sessions. A higher score on the PCFS and more days on IMV were associated with the increased likelihood of needing more sessions, whereas more meters on the 6MWT in the initial evaluation was associated with a reduced likelihood of needing more sessions. Finally, more repetitions on the STS and less distance covered on the initial 6MWT were associated with a greater improvement in exercise performance evaluated with the 6MWT. CONCLUSION: Supervised and individualized PRP for patients with severe post-COVID-19 improves pulmonary function, exercise performance, functionality, and quality of life. Functionality, distance covered on the 6MWT, and the days on IMV are central to the scheduling of the number of sessions for these patients.

Prognostic value of exercise longitudinal right ventricular free wall strain in patients with sickle cell disease.

Longitudinal right ventricular free wall strain (RVFWS) has been identified as an independent prognostic marker in patients with pulmonary hypertension. Little is known however about the prognostic value of RVFWS in patients with sickle cell (SC) disease, particularly during exercise. We therefore examined the prognostic significance of RVFWS both at rest and with exercise in patients with SC disease and normal resting systolic pulmonary artery pressure (SPAP). Consecutive patients with SC disease referred for bicycle ergometer stress echocardiography (SE) were enrolled ftom July 2019 to January 2021. All patients had measurable tricuspid regurgitation velocity (TRV). Conventional echocardiography parameters, left ventricular global longitudinal strain (LVGLS), RVFWS, and ventriculoarterial coupling indices (TAPSE/SPAP and RVFWS/SPAP) were assessed at rest and peak exercise. Repeat SE was performed at a median follow-up of 2 years. The cohort consisted of 87 patients (mean age was 31 ± 11 years, 66% females). All patients had normal resting TRV < 2.8 m/s, RVFWS and LVGLS at baseline. There were 23 (26%) patients who had peak stress RVFWS < 20%. They had higher resting and peak stress TRV and SPAP, but lower resting and peak stress TAPSE/SPAP, RVFWS/SPAP, and LVGLS as well as lower peak stress cardiac output when compared to patients with peak stress RVFWS ≥ 20% (p < 0.05). Patients with baseline peak stress RVFWS < 20% had a significant decrease in exercise performance at follow-up (7.5 ± 2.7 min at baseline vs. 5.5 ± 2.8 min at follow-up, p < 0.001). In the multivariate analysis, baseline peak stress RVFWS was the only independent predictor of poorer exercise performance at follow-up [odds ratio 8.2 (1.2, 56.0), p = 0.033]. Among patients with SC disease who underwent bicycle ergometer SE, a decreased baseline value of RVFWS at peak stress predicted poorer exercise time at follow-up.

The Effect of Creatine Nitrate and Caffeine Individually or Combined on Exercise Performance and Cognitive Function: A Randomized, Crossover, Double-Blind, Placebo-Controlled Trial.

This study examined the effect of creatine nitrate and caffeine alone and combined on exercise performance and cognitive function in resistance-trained athletes. In a double-blind, randomized crossover trial, twelve resistance-trained male athletes were supplemented with 7 days of creatine nitrate (5 g/day), caffeine (400 mg/day), and a combination of creatine nitrate and caffeine. The study involved twelve resistance-trained male athletes who initially provided a blood sample for comprehensive safety analysis, including tests for key enzymes and a lipid profile, and then performed standardized resistance exercises-bench and leg press at 70% 1RM-and a Wingate anaerobic power test. Cognitive function and cardiovascular responses were also examined forty-five minutes after supplementation. Creatine nitrate and caffeine that were co-ingested significantly enhanced cognitive function, as indicated by improved scores in the Stroop Word-Color Interference test (p = 0.04; effect size = 0.163). Co-ingestion was more effective than caffeine alone in enhancing cognitive performance. In contrast, no significant enhancements in exercise performance were observed. The co-ingestion of creatine nitrate and caffeine improved cognitive function, particularly in cognitive interference tasks, without altering short-term exercise performance. Furthermore, no adverse events were reported. Overall, the co-ingestion of creatine nitrate and caffeine appears to enhance cognition without any reported side effects for up to seven days.

Combined effects of Rhodiola rosea and caffeine supplementation on aerobic endurance and muscle explosiveness: a synergistic approach.

This study examined the synergistic effects of combining Rhodiola rosea (RHO) and caffeine (CAF) supplementation on muscle endurance and explosiveness in SD rats and human subjects, encompassing individuals without prior exercise training experience and seasoned aerobic athletes. Male SD rats and healthy human volunteers were randomly divided into four groups: CAF, RHO, CAF + RHO, and a control group (CTR). Nutritional supplements were administered throughout the training period, and pre-and post-measurement data were collected. In both the rat model and human subjects, the RHO+CAF group demonstrated significantly greater effects compared to the use of RHO or CAF supplements individually. Rats in the RHO+CAF group demonstrated extended running and swimming times and an increase in erythropoietin (EPO) mRNA expression in comparison to the CTR. Blood parameters, such as serum EPO levels, were enhanced in the CAF + RHO group, while blood urea nitrogen (BUN) and lactate (LA) levels significantly decreased in both the RHO and CAF + RHO groups. Hepatic and muscle glycogen contents were also higher in these groups. The gene expression analysis in rats demonstrated an elevation in the mRNA levels of glucose transporter-4 (GLUT-4), peroxisome proliferator-activated receptor γ coactivator-1 alpha (PGC-1α), Monocarboxylate transporter 1 (MCT-1), and Heme Oxygenase-1 (HO-1) in both the RHO and RHO+CAF groups. For individuals without prior aerobic training experience, the RHO+CAF group showed significant improvements compared to the CTR group in maximal oxygen consumption (VO2max), 5 km run, countermovement jump (CMJ), standing long jump, and 30 m sprint. For individuals with years of aerobic training experience, the RHO+CAF group exhibited enhanced performance in the 5 km run, CMJ, and standing long jump compared to the CTR group. In conclusion, the continuous 30 days supplementation of RHO, combined with a single dose of CAF, demonstrated superior effects on muscle endurance and explosiveness in both animal and human studies when compared to the use of RHO or CAF individually.

High-intensity interval training improves respiratory and cardiovascular adjustments before and after initiation of exercise.

Purpose: High-intensity interval training (HIIT) may induce training-specific physiological adaptations such as improved respiratory and cardiovascular adjustments before and after the onset of high-intensity exercise, leading to improved exercise performance during high-intensity exercise. The present study investigated the effects of HIIT on time-dependent cardiorespiratory adjustment during maximal exercise and before and after initiation of high-intensity exercise, as well as on maximal exercise performance. Methods: 21 healthy male college students were randomly assigned to HIIT group (n = 11) or control group (n = 10). HIIT group performed training on a cycle ergometer once a week for 8 weeks. The training consisted of three bouts of exercise at 95% maximal work rate (WRmax) until exhaustion. Before and after the HIIT program, dynamic cardiorespiratory function was investigated by ramp and step exercise tests, and HIIT-induced cardiac morphological changes were assessed using echocardiography. Results: HIIT significantly improved not only maximal oxygen uptake and minute ventilation, but also maximal heart rate (HR), systolic blood pressure (SBP), and time to exhaustion in both exercise tests (p < 0.05). Time-dependent increases in minute ventilation (VE) and HR before and at the start of exercise were significantly enhanced after HIIT. During high-intensity exercise, there was a strong correlation between percent change (from before to after HIIT program) in time to exhaustion and percent change in HRmax (r = 0.932, p < 0.001). Furthermore, HIIT-induced cardiac morphological changes such as ventricular wall hypertrophy was observed (p < 0.001). Conclusion: We have demonstrated that HIIT at 95% WRmax induces training-specific adaptations such as improved cardiorespiratory adjustments, not only during maximal exercise but also before and after the onset of high-intensity exercise, improvement of exercise performance mainly associated with circulatory systems.

Assessment of the Relationship between Periodontitis and Cardiac Parameters in Patients with Early Chronic Heart Failure: A Cross-Sectional Study.

Periodontal disease (PD) is considered a risk factor for cardiovascular events. However, its relationship to chronic heart failure (CHF) is unclear. The aim was to compare cardiac and inflammatory parameters in CHF patients with (PG) versus without periodontitis (NPG). The following parameters were recorded in 58 patients: periodontal screening and recording (PSR), troponin T, NT-proBNP, C-reactive protein (CRP), interleukin-6 (IL-6), blood pressure, heart rate, ejection fraction (EF), ventricular systolic and diastolic function parameters, incremental test, and three questionnaires (Mediterranean Diet Adherence Screener, MEDAS; Oral Health Impact Profile, OHIP-14; Patient Health Questionnaire, PHQ). The serum levels of NT-proBNP and troponin T were significantly higher in the PG, and the left ventricular systolic and diastolic function parameters were significantly lower. The correlation analysis showed age as the only independent risk factor for periodontitis and cardiac biomarkers. No significant group differences were found in the MEDAS, OHIP-14, and PHQ scores, or in CRP, IL-6, and cardiocirculatory parameters. Overall, the BMI correlated significantly with the mean PSR and total cholesterol. The occurrence of increased PSR together with increased age and cardiac risk parameters does not exclude an association between periodontitis and CHF, though no positive correlation was calculated. Periodontitis may be a modifiable risk factor for CHF. Its treatment may help to control the inflammatory burden.