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    Acute Caffeine Ingestion, Calendar-Based Menstrual-Cycle Window, Time of Day, and Match-Induced Fatigue Independently and Interactively Influence Psychophysiological, Cognitive, and Physical Performance in Elite Female Volleyball Players: A Randomized Double-Blind Placebo-Controlled Crossover Design Study
    (MDPI, 2026) Seddik, Meher; Dhahbi, Wissem; Bessifi, Manel; Moussa-Chamari, Imen; Ceylan, Halil Ibrahim; Ceylan, Nagihan Burcak; Souissi, Nizar
    Aim: Female athletic performance is shaped by the convergence of menstrual-cycle timing, circadian rhythms, fatigue, and ergogenic supplementation; yet no prior study has examined these factors simultaneously in a sport-specific setting. This study investigated the independent and combined effects of acute caffeine ingestion, calendar-based testing window, time of day, and match-induced fatigue on psychophysiological, cognitive, and physical performance in trained female volleyball players. Methods: Thirteen elite eumenorrheic female volleyball players (age: 24.23 +/- 4.06 years) completed a randomized, double-blind, placebo-controlled crossover protocol comprising 12 sessions corresponding to all combinations of testing window (menstrual, follicular, luteal), supplementation (caffeine 6 mg & centerdot;kg(-1) vs. placebo), and time of day (08:00 h vs. 18:00 h). Assessments included the Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Spiegel questionnaire, Profile of Mood States, Hooper Index, Stroop task, Countermovement Jump (CMJ), Modified Agility T-Test (MAT), and Reactive Agility Test (RAT), administered before and after a one-hour simulated match. Results: Significant main effects of testing window, caffeine, time of day, and fatigue state were observed across all outcome domains (all p < 0.05). Caffeine reduced daytime sleepiness (F(1,12) = 23.84, p < 0.001, eta p(2) = 0.665), enhanced vigor (F(1,12) = 114.10, p < 0.001, eta p(2) = 0.905), and improved MAT performance (F(1,12) = 33.27, p < 0.001, eta p(2) = 0.735). The follicular window was associated with superior cognitive, neuromuscular, and mood-related outcomes relative to the menstrual and luteal windows. Exploratory higher-order interactions suggested condition-specific caffeine benefits for MAT, RAT, and CMJ, particularly in afternoon post-fatigue conditions; these patterns require replication in larger samples. Conclusions: Acute caffeine ingestion improved several psychophysiological, cognitive, and neuromuscular outcomes in trained female volleyball players, with effects that varied across calendar-based testing windows, time of day, and fatigue state. Individualized supplementation strategies incorporating cycle timing and circadian context remain investigational; prescriptive recommendations require replication in larger, hormonally verified samples before clinical or applied adoption.
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    High Prevalence of Malnutrition and Sarcopenia with Inadequate Nutritional Support in Intensive Care Unit Patients: A Prospective Observational Study of Clinical Outcomes
    (MDPI, 2026) Ben Othman, Rym; Cherni, Asma; Dergaa, Ismail; Ceylan, Halil Ibrahim; Ceylan, Nagihan Burcak; Stefanica, Valentina; Jamoussi, Henda
    Background: Malnutrition and sarcopenia are highly prevalent in intensive care settings and are associated with adverse clinical outcomes. Aim: The study aimed to evaluate the association between nutritional care, nutritional status, and patient outcomes in intensive care units. Methods: This prospective observational study at a Tunisian tertiary hospital investigated nutritional status and management of 100 intensive care unit patients, each of whom was followed for seven days after ICU admission. Malnutrition Risk was assessed by NUTRIC and MNA scores. The severity of disease was assessed using the APACHE II and SOFA scores. Malnutrition was diagnosed using body mass index and weight loss. Sarcopenia was assessed through grip strength, calf circumference, and psoas muscle area. Nutritional management was evaluated using calculations of caloric and protein intake. Clinical outcomes included the need for intubation, difficulty with oxygen weaning, healthcare-associated infections, and the development of pressure ulcers. Results: The participants had a mean age of 54.85 +/- 17.25 years, with a slight male predominance (53 males, 47 females). Pre-existing metabolic conditions affected 80% of patients, including hypertension (40 patients), diabetes (36), and obesity (18). The primary reasons for admission were respiratory disorders (25%), infectious diseases (23%), and metabolic disorders (16%). The mean APACHE II score was 15.91 +/- 6.84, and the mean NUTRIC score was 3 +/- 1.66; 27% were classified as at high risk of malnutrition. The prevalence of malnutrition reached 50% (28% moderate, 22% severe). Only 31% received adequate caloric intake, while 84% had insufficient protein intake. Malnourished patients required intubation more frequently (50% versus 22.5%; p = 0.014), experienced greater difficulty with oxygen weaning (78.4% versus 48.6%; p = 0.008), and developed pressure ulcers more often (43.5% versus 6%; p < 0.001). Sarcopenic patients showed similar patterns for intubation (51.4% versus 18.9%, p = 0.003), oxygen weaning difficulty (77.5% versus 46.9%, p = 0.007), and pressure ulcers (39.2% versus 6.7%, p < 0.001). Conclusions: Malnutrition and sarcopenia are highly prevalent in intensive care patients and are associated with severe complications, including prolonged mechanical ventilation and pressure ulcer development. Inadequate nutritional support remains common despite known consequences. Early comprehensive nutritional assessment and appropriate management from admission are essential to improve outcomes in critically ill patients.
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    Progressive Smartphone Restriction Combined with Psychoeducational Guidance and Pre-Sleep Autonomic Regulation Improves Sleep Efficiency and Time-of-Day Cognitive Performance in Physically Active Students with Nomophobia: A Randomized Controlled Trial
    (MDPI, 2026) Ben Alaya, Wiem; Dhahbi, Wissem; Souissi, Mohamed Abdelkader; Jebabli, Nidhal; Ceylan, Halil Ibrahim; Ceylan, Nagihan Burcak; Souissi, Nizar
    Aim: This study compared the effects of standard evening smartphone restriction with an adapted intervention combining progressive restriction, psychoeducational guidance, and pre-sleep relaxation on sleep, psychological state, cognitive performance, and physical performance in physically active physical education students with moderate-to-high nomophobia. Methods: Thirty participants (age 21.9 +/- 1.2 years; intermediate chronotype) completed a randomized controlled trial consisting of a 7-day baseline period, a 14-day intervention phase, and post-intervention assessments. The standard group (n = 15) implemented a 2-h pre-bedtime smartphone restriction combined with general sleep hygiene guidance. The adapted group (n = 15) followed a progressive restriction protocol (30 -> 60 -> 120 min) supplemented with psychoeducational guidance targeting smartphone-related anxiety and a nightly slow-paced breathing routine. Objective sleep parameters were quantified using wrist-worn actigraphy. Subjective sleep quality, pre-sleep anxiety, and stress were assessed using visual analog scales. Cognitive performance (psychomotor vigilance task and choice reaction time) and physical performance (vertical jumps and agility) were evaluated at both morning and afternoon time points. Results: The adapted intervention produced significantly greater improvements in sleep efficiency (time & times; group: F(1,28) = 6.84, p = 0.014, eta p2 = 0.20; d = 0.78) and sleep onset latency (F(1,28) = 5.97, p = 0.021, eta p2 = 0.18; d = 0.72) compared with standard restriction. Significant reductions were also observed in pre-sleep anxiety (F(1,28) = 7.12, p = 0.012, eta p2 = 0.20; d = 0.81) and stress (F(1,28) = 6.45, p = 0.017, eta p2 = 0.19; d = 0.74). Cognitive performance showed significant time & times; group & times; time-of-day interactions, with improvements during afternoon assessments in psychomotor vigilance (F(1,28) = 7.48, p = 0.011; d = 0.83) and choice reaction time (F(1,28) = 6.89, p = 0.014; d = 0.79) exclusively in the adapted group. Physical performance outcomes remained stable across interventions. Conclusions: Progressive smartphone restriction combined with psychoeducational strategies and pre-sleep relaxation yields clinically meaningful improvements in sleep continuity, psychological arousal, and afternoon cognitive performance, exceeding the benefits achieved through behavioral restriction alone.
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    Ramadan intermittent fasting alters cardiac autonomic modulation, neuromuscular performance, and recovery in adolescent tennis players: a within-subject repeated-measures design
    (Taylor & Francis Ltd, 2026) Lakhdar, Nadia; Landolsi, Mounir; Ghouili, Hatem; Ceylan, Halil Ibrahim; Ceylan, Nagihan Burcak; Muntean, Raul Ioan; Dergaa, Ismail
    Background: Tennis requires repeated high-intensity efforts with brief recovery periods, placing significant demands on cardiac autonomic regulation and neuromuscular performance. Ramadan intermittent fasting alters sleep, nutrition, and hydration patterns, potentially affecting match responses, particularly in adolescents. Methods: Sixteen male International Tennis Federation (ITF) junior players completed a within-subject repeated-measures study during mid-Ramadan and 15 days post-Ramadan. Each performed a standardized two-set outdoor match under both conditions. Heart rate variability (HRV), countermovement jump (CMJ), blood glucose, hydration markers, and rating of perceived exertion were assessed at baseline (T0), between sets (T1), and post-match (T2). Sleepiness, chronotype, fatigue, and recovery were evaluated via validated questionnaires. Results: Match play reduced lnRMSSD (p < 0.001, eta p(2 )= 0.775) and increased LF/HF (p < 0.001, eta p(2)= 0.234), indicating sympathetic dominance. During Ramadan, parasympathetic activity was lower (p < 0.001, eta p(2)= 0.269), and CMJ performance was reduced (p = 0.010, eta p(2)= 0.085). Blood glucose showed a Period & times; Set interaction (p = 0.020,eta p(2) = 0.114). Sleepiness, fatigue, and perceived recovery were significantly impaired (p < 0.001). Conclusion: Ramadan intermittent fasting reduces vagal activity and impairs neuromuscular performance in adolescent tennis players. HRV-guided training, optimized nutrition, and sleep management may help mitigate these effects.