The relationship between sleep- and circadian rhythm-related parameters with dietary practices and food intake of sedentary adults: a cross-sectional study.

We aimed to explore the link between sleep-related parameters and dietary practices. This cross-sectional exploratory study includes sedentary individuals between 20 and 59 years of age. We applied exigent inclusion and exclusion criteria, such as weight stability and without humor- or sleep-related diseases. Also, shift workers were not included. We evaluated sleep quality (by Pittsburg Sleep Quality Index; PSQI), sleepiness (by Epworth Sleepiness Scale), chronotype (by Morningness Eveningness Questionnaire; MEQ), and social jetlag from sleep dairy. Moreover, Food Practices Measurement Scale was used to assess dietary practices. Food intake estimates (i. e., energy, eating window, and late-night dinner eating) were derived from two 24-h food recalls (R24h). For analysis, dietary practices and energy intake from R24h were considered dependent variables, while PSQI, ESS, MEQ, STJ, EW, and LNDE were considered independent variables. Our sample comprises 42 adults (21 women and 21 men; 35.4 (12.5) y; 25.6 (5.21) kg/m2 BMI; 26.5 (7.97) % body fat). We verified that persons with poor sleep quality showed lower dietary practice scores (MD - 6.68; p = 0.021). Besides, in regression analysis, chronotype (ß = 0.266; p = 0.039) was positively associated with dietary practices, and eating window was positively associated with energy intake (ß = 267 kcal; p = 0.023). In contrast to our hypothesis, other sleep- and circadian-related variables were not associated with dietary practices or energy intake. In summary, we conclude that morning chronotype appears to be related to better dietary practices from the Food Guide for the Brazilian Population guide and that higher eating window was positively associated with energy intake.

Household food insecurity among child and adolescent athletics practitioners: A cross-sectional, descriptive, and exploratory study.

OBJECTIVE: The aim of the study was to explore the prevalence of food insecurity among child and adolescent athletics practitioners and to investigate factors associated with exercise performance, dietary habits, body composition, sleep, and socioeconomic status based on food security status. METHODS: This was a cross-sectional, descriptive, and exploratory study conducted in Campinas, São Paulo, Brazil, between June and July 2023. The convenience sample included children and adolescents (7-17 y old) of both sexes. We evaluated exercise performance, household food insecurity (HFI), dietary-related parameters, and other body composition, lifestyle, and social-related variables. Exercise performance was assessed using the counter movement jump (CMJ), squat jump (SJ), horizontal long jump (HLJ), 50-m sprint test (50-m ST) and throwing strength test (TST). The assessment of HFI was conducted using the food insecurity experience scale (FIES). Comparisons and associations were investigated based on food security status. RESULTS: The total sample size was comprised of 138 children (n = 42; 30.4%) and adolescents (n = 96; 69.6%). We found an association between food security status and sex (X2(138,1) = 4.42; P = 0.036). SJ was higher in the food security group than in the HFI group (t(117) = 2.112; P = 0.037; ES = 0.39). Sleep- and dietary-related factors did not differ between the groups. CONCLUSIONS: In summary, the prevalence of HFI among child and adolescent athletics participants was approximately 40%. Regarding exercise performance, SJ was better in the food security group than in the HFI group. Concerning dietary-related data, the HFI group had a lower number of meals per day than the food security group, and other dietary data did not differ between the groups. Body composition and sleep-related parameters were similar between the groups.

Physical fitness, hormonal profile, nutritional and psychological aspects assessment of transgender women volleyball players submitted to physical tests: protocol paper of a prospective cohort.

To evaluate aerobic capacity, strength and other physiological, nutritional, and psychological variables which may influence the performance of transgender women (TW) athletes and compare them to cisgender women (CW) and cisgender men (CM) athletes, as well as changes in TW performance over the course of a year. Prospective cohort study including three groups: TW, CW and CM volleyball athletes. Subjects will be comprehensively assessed at two different moments: baseline and after 6-12 months of adequate hormonal therapy. Evaluation will comprise clinical, medical, nutritional and psychological interviews, incremental treadmill cardiopulmonary exercise testing, hand grip strength test, vertical jump test, analysis of sleep quality (Pittsburgh Sleep Quality Index), hormonal profile, echocardiogram, analysis of resting energy expenditure, assessment of bone mass and body composition through dual-energy X-ray absorptiometry scans, and untargeted metabolomic analysis. CW and CM matched by age, body mass index and level of physical activity will undergo a similar evaluation. The assessment of the strength, aerobic capacity, haematological, nutritional and psychological status of TW using gold-standard tests will contribute to understanding the impact of oestrogen therapy on the exercise performance of these athletes and how they compare with CW and CM.

Prevalence of dietary supplement consumption among CrossFit practitioners.

Purpose: We aimed to verify the prevalence of dietary supplements among CrossFit practitioners (CFPs), considering gender and training status. Still, we aimed to determine the type, reasons, and associated factors of dietary supplement utilization among CFPs. Methods: This is a cross-sectional, exploratory, and descriptive study with the snowball sampling method. Data were collected through online questionnaires using the Google Forms® tool. We included CFPs aged 18-64 years, from Aug 1, 2020, to Sept 31, 2020. The questionnaire contained questions to assess the prevalence, type, and reasons for supplement use; also, we assessed information about sociodemographic variables and the prevalence of the main chronic morbidities. To analyze aspects of eating behavior and sleep-related parameters, we applied the three-factor eating questionnaire (TFEQ)-R21 and the Pittsburgh Sleep Quality Index questionnaire (PSQI), respectively. Results: We assessed one hundred twelve (n = 112; 57 men; 55 women) CFPs (28.9 ± 7.64 years old; body mass index (BMI), 25.5 ± 4.83 kg/m2). Eighty-seven (50 men; 37 women; 28.2 ± 6.66 years old; BMI, 25.4 ± 4.55 kg/m2) reported using dietary supplements. Whey protein was the most used supplement (n = 70), followed by creatine (n = 54). Cognitive restraint (a dimension of eating behavior) score was higher in supplement users than in non-users (51.7 ± 18.6 vs. 42.6 ± 20.5; p = 0.040). Sleep-related parameters did not differ between supplement users and non-users. The most associated factors to supplement use were sex (being man; OR, 7.99; p = 0.007), sleep quality (poor; OR, 5.27; p = 0.045), CrossFit level (as prescribed (RX); OR, 4.51; p = 0.031), and cognitive restraint (OR, 1.03; p = 0.029). Conclusion: The CFPs, especially RX and Elite ones, showed a higher prevalence of supplement utilization. Anabolic-related supplements (i.e., whey protein and creatine) were the most used; moreover, several CFPs used supplements not supported by scientific evidence. Cognitive restraint score was higher in supplement users than in non-users. RX level, being men, and poor sleep quality were associated with supplement utilization. These data draw attention to the necessity of nutritional education for CrossFit coaches and athletes. Broader studies are necessary to confirm our findings.

Effect of oral contraceptive use on weight loss and body composition following low-calorie diet intervention.

BACKGROUND: Energy restriction promoted by hypocaloric diets is one of the most studied interventions to achieve weight loss. However, there are many factors which may influence the weight loss process. Hormonal contraception is an important factor to be investigated. PURPOSE: To evaluate the effect of oral contraceptive use on weight loss following 500-kcal reduction diet intervention for 1-month. METHODS: We conducted a single-blind controlled study in which 19 healthy women aged 18-25 years were divided into oral contraceptive use group (COC, n = 9) or no hormonal contraception use group (NHC, n = 10). Anthropometric measurements were assessed at baseline and after 4 weeks of intervention. RESULTS: Both COC and NHC groups achieved significant body weight, body fat, and lean body mass loss following 4 weeks of caloric restriction diet intervention. COC group lost more weight (2.87 kg) than NHC group (1.36 kg) (p < 0.001). CONCLUSION: In a month's time, daily reduction of 500-kcal resulted in reduction of body weight and body fat. COC group lost more weight than NHC group. Given the limitations of the study, these data should be interpreted with caution. More studies are necessary to verify the effects of oral contraceptive use on weight loss.

Does Modern Lifestyle Favor Neuroimmunometabolic Changes? A Path to Obesity.

Factors linked to modern lifestyles, such as physical inactivity, Western diet, and poor sleep quality have been identified as key contributors to the positive energy balance (PEB). PEB rises adipose tissue hypertrophy and dysfunction over the years, affecting cells and tissues that are metabolically critical for energy homeostasis regulation, especially skeletal muscle, hypothalamic-pituitary-adrenal axis, and gut microbiota. It is known that the interaction among lifestyle factors and tissue metabolic dysfunction increases low-grade chronic systemic inflammation, leading to insulin resistance and other adverse metabolic disorders. Although immunometabolic mechanisms are widely discussed in obesity, neuroimmunoendocrine pathways have gained notoriety, as a link to neuroinflammation and central nervous system disorders. Hypothalamic inflammation has been associated with food intake dysregulation, which comprises homeostatic and non-homeostatic mechanisms, promoting eating behavior changes related to the obesity prevalence. The purpose of this review is to provide an updated and integrated perspective on the effects of Western diet, sleep debt, and physical exercise on the regulation of energy homeostasis and low-grade chronic systemic inflammation. Subsequently, we discuss the intersection between systemic inflammation and neuroinflammation and how it can contribute to energy imbalance, favoring obesity. Finally, we propose a model of interactions between systemic inflammation and neuroinflammation, providing new insights into preventive and therapeutic targets for obesity.

Effects of diet interventions, dietary supplements, and performance-enhancing substances on the performance of CrossFit-trained individuals: A systematic review of clinical studies.

CrossFit (CF) is characterized as a constantly varied, high-intensity, functional movement training program, performed with little or no rest between bouts, combining strength and endurance exercises, such as running, cycling, rowing, Olympic weightlifting, power weightlifting, and gymnastic-type exercises. Several nutritional strategies are used to improve sports performance of CF practitioners; however, most of them are empirical and lack scientific evidence. Thus, the aim of this review was to determine the effects of diet intervention, dietary supplements, and performance-enhancing substances on exercise-performance parameters of CF practitioners. MEDLINE/PubMed, Web of Science, LILACS, SciELO, and Scopus databases were searched using specific Medical Subject Headings and keywords for clinical studies that enrolled CF athletes in an intervention using diet, dietary supplements, or performance-enhancing substances. Athletic performance was considered as the primary outcome. No other filters were applied. Including grey literature search, 219 studies were identified; however only 14 studies met the eligibility criteria. Two studies evaluated the effects of caffeine supplementation on exercise performance; five studies evaluated high- or low-carbohydrate effects on performance and other parameters. One study verified the effects of multi-ingredient supplementation on CF-specific performance and body composition. One study compared the intake of protein supplements on performance and body composition. Two studies assessed the effect of green tea and (-)-epicatechin on performance and other parameters. One study evaluated the effects of nitrate supplementation on exercise performance. One study investigated the effect of betaine supplementation on body composition and muscle performance. Finally, one study examined the effects of sodium bicarbonate (SB) ingestion on exercise performance and aerobic capacity. Only SB supplementation improved CF performance. These outcomes may have been obtained due to methodological limitations such as small sample size, lack of control over influencing variables, short period of exercise intervention. Despite the popularity and growing evidence about CF, little is known about the relationship between performance-enhancing substances or dietary interventions and CF performance. Given the lack of scientific evidence, new studies with potential ergogenic supplements, a better methodological model, and practical application are required.

The influence of acute hypoxic exposure on isokinetic muscle force production.

To investigated whether an acute hypoxic stimulus affects muscle strength development assessed by isokinetic dynamometry during maximal knee extension. A total of 15 healthy young men participated in this study (61.9 ± 6.1 kg; 1.72 ± 0.08 m; 20.9 ± 2.6 years). We evaluated knee extension and flexion isokinetic dynamometer performance in normoxic and hypoxic conditions. The analyzed parameters, for concentric contraction, were peak torque and total work measured at 1.05 and 5.23 rad/s; and fatigue index measured at 5.23 rad/s. During isokinetic testing, heart rate and oxygen saturation (SpO2) were monitored. Hypoxic conditions (3,600 m) were simulated, via a mixing chamber, with the dilution being constantly controlled by a PO2 probe. Test reproducibility results (test-retest) for all isokinetic knee parameters were classified as moderate to almost perfect (ICC = 0.694 to 0.932). SpO2 was 88.4 ± 3.4% in the hypoxic condition and 97.1 ± 0.7% in the normoxic condition (p = 0.000, effect size = 0.87). Heart rate was not significantly different between normoxic and hypoxic conditions at the end of the test. There were no significant differences in isokinetic variables evaluated for the extensor and flexor muscles at concentric contraction between the normoxic and hypoxic conditions. Our findings indicate that reduced arterial oxygenation per se has no effect on the muscular isokinetic strength of the knee extensors.

Assessment of functional impairment after knee anterior cruciate ligament reconstruction using cardiorespiratory parameters: a cross-sectional study.

BACKGROUND: A dynamic sub-maximum exercise with the same absolute intensity, performed with different muscle groups, may present exacerbated cardiorespiratory responses. Therefore, cardiorespiratory responses to unilateral exercise may identify bilateral differences. The purpose of this study was to verify whether the cardiorespiratory responses to lower limb exercise display counter-lateral differences, and if they could be used to assist athletes and health professionals involved in rehabilitation. METHODS: Nine individuals participated in this cross-sectional study. They had been treated in a private rehabilitation clinic and submitted to intra-articular reconstruction of the anterior cruciate ligament. The cycling exercise with the same sub-maximal intensity and with one lower limb was used to gather data. Cardiorespiratory responses to exercise were compared between exercises performed with the involved and uninvolved limb after five minutes of exercise. RESULTS: Cardiorespiratory responses to exercise performed with the involved limb presented higher values after five minutes of cycling: oxygen uptake (+7%), carbon dioxide production (+10%), minute ventilation (+20%), breathing frequency (+19%), ventilatory equivalent for oxygen (+14%), end-tidal pressure of O2 oxygen (+4%), end-tidal pressure of O2 carbon dioxide (-9%) and heart rate (+9%). CONCLUSIONS: The exacerbated responses, including increase of the ventilatory equivalent and decrease of end-tidal pressure of carbon dioxide, indicate that this exercise protocol may be useful in the characterization of the functional deficit of the surgical limb during rehabilitation.

Skeletal muscle ergoreflex overactivity is not related to exercise ventilatory inefficiency in non-hypoxaemic patients with COPD.

Increased ventilatory response to the metabolic demand ("ventilatory inefficiency") is commonly found during dynamic exercise in patients with chronic obstructive pulmonary disease (COPD). However, the role of enhanced muscle ergoreflex activity on this phenomenon is yet unknown. Ten non-hypoxaemic patients with varying degrees of disease severity (median and range of post-bronchodilator FEV(1) = 37.5 (27 to 70%) predicted) and 7 age- and gender-matched controls were studied. Subjects were submitted to wrist flexion tests to the limit of tolerance (Tlim) with and without post-exercise regional circulatory occlusion (PE-RCO) for 3 min. The muscle ergoreflex activity was quantified as the difference in ventilation between PE-RCO and control recovery periods corrected for the resting values (ergoreflex Delta). In addition, the area under the ventilatory curve in the recovery period was calculated in both conditions. We found that Tlim and the physiological stress associated with localized exercise did not differ between patients and controls. However, patients had increased ventilatory response to a given metabolic demand (VCO(2)), either at rest or during exercise (P < 0.05). There were no significant differences in ergoreflex Delta in patients and controls (-2.2 to 2.4 (0.2) vs. -0.6 to 1.8 (0.3) l/min, respectively). In addition, the area under the ventilatory curve in the recovery period did not differ between control and PE-RCO tests in patients and healthy subjects (P > 0.05). We conclude that increased muscle ergoreflex activity did not contribute to an excessive ventilatory response to exercise in patients with COPD-at least in non-hypoxaemic and non-cachetic subjects.