Search Results (1,970)

Mental fatigue is a psychobiological state induced by sustained effortful cognitive efforts during daily life activities. Yet research efforts in exercise science have focused primarily on performance implications for athletes to the point of exclusion of vulnerable populations for which mental fatigue may be a health risk. This narrative review aims to clarify the role of mental fatigue on population health. Evidence suggest mental fatigue predisposes people to acute events related to temporary performance impairments (e.g., falls), and chronic diseases related to sedentarism (e.g., stroke, diabetes), as mental fatigue de-motivates people to engage in physical activity. Major risks are experienced by people with higher fatigability (i.e., people for whom mental fatigue is induced by less effortful tasks) and lower performance capacity. However, the few available information about moderators of fatigability and the lack of a normative protocol to assess mental fatigue are limiting the prevention of mental fatigue. Several strategies are used to counter mental fatigue acutely (e.g., caffeine ingestion); however, enduring countermeasures intended to alter psychobiological sequelae of mental fatigue, such as Brain Endurance and other trainings, are the only proved long-term countermeasures for mental fatigue. Yet the effectiveness of these interventions should be tested in populations with major risk for mental fatigue. We present a model identifying putative pathways through which mental fatigue may contribute to health risks to guide future investigations seeking to (a) evaluate the role of mental fatigue as a threat to health and well-being and (b) design interventions to mitigate the effects of mental fatigue in vulnerable populations. Full article

Kucha, a unique tea germplasm rich in theacrine, imparts its fresh leaves with a particularly bitter taste and multiple bioactivities. However, systematic studies on processed Kucha—especially white tea—remain limited. In this study, white teas were produced from two Yunnan Kucha accessions (YLKC1, YLKC2) and two conventional cultivars. Their quality characteristics and non-volatile metabolic profiles were systematically compared using sensory evaluation, targeted quantification and widely targeted metabolomics. Results indicated that Kucha white teas displayed pronounced bitterness, with YLKC1 presenting a richer, well-layered flavor, indicating promising quality potential. Targeted quantification demonstrated a remarkably high theacrine content (~30 mg/g) in Kucha white teas, whereas caffeine and several catechin monomers were significantly lower than those in conventional cultivars. Widely targeted metabolomic analysis identified 3376 non-volatile metabolites. PCA and OPLS-DA demonstrated a clear separation in metabolic profiles between Kucha and control groups. In total, 601 significantly differential metabolites were identified. Taste-driven annotation against ChemTastesDB revealed 17 known bitter compounds, 10 of which were significantly accumulated in Kucha white tea—including theacrine, theophylline, theobromine, L-arginine, neohesperidin, pinocembrin, kaempferol-3-O-(6”-malonyl)glucoside, fraxin, adenosine, and xanthine. Among these compounds, theacrine showed the highest upregulation (9.30-fold). In addition, several galloylated flavonoid glycosides also exhibited significant accumulation. KEGG enrichment analysis further indicated that flavonoid biosynthesis and caffeine metabolism were crucial pathways contributing to these metabolic differences. Collectively, these findings demonstrate that the characteristic bitterness of Kucha white tea arises from the coordinated accumulation of a specific set of bitter phytochemicals rather than a single compound and provide a prioritized panel of candidate compounds for flavor-oriented breeding and processing. Full article

Photocatalytic processes have been studied as promising solutions to mitigate the impact of pollutants on aquatic environments. Here, the enhancement of photocatalytic performance and stability of titanate nanostructures (TNS), a well-established photocatalyst, were investigated through Sr modification. Structural characterization confirmed Sr in-corporation in the crystalline structure, mainly in the interlayers. The sample Sr(5%)TNS, synthesized with 5% (wt.), exhibited fine lamellar morphology, different from the elongated nanowires of pristine TNS. The photocatalytic performance of the Sr-modified sample was studied for the removal of a model pollutant, caffeine, under UV-Vis and visible irradiation. A clear enhancement in the caffeine removal rate was observed using Sr(5%)TNS as a photocatalyst, when compared with the pristine material. Further improvement in the photocatalytic performance was obtained by combining Sr(5%)TNS with graphitic-like carbon nitride (g-C₃N₄) as a novel composite film. This proved to be a promising strategy for enhancing both the visible-light photocatalytic efficiency and the stability of the films, while also facilitating their reuse. Various configurations of the hybrid system were tested, and the best results for caffeine degradation and catalyst robustness were achieved with a 4:1 ratio of Sr(5%)TNS to g-C₃N₄. Mechanisms for charge transfer in irradiated Sr(5%)TNS particles, and in Sr(5%)TNS/g-C₃N₄ composite films are proposed and discussed. Full article

Background/Objectives: Lower urinary tract symptoms (LUTSs), particularly nocturia and urgency, often intensify during the menopause transition and may worsen with caffeine intake and cold exposure. This review aims to synthesize evidence relevant to a hypothesized caffeine–cold interaction in transitional menopause, focusing on water homeostasis and the estrogen–transient receptor potential melastatin 8 (TRPM8) cold-sensory axis, and to propose potentially actionable, nutrition-centered intervention candidates for future testing. Methods: Structured narrative review of PubMed, Embase, Web of Science, and citation tracking (inception–January 2026). Evidence was mapped into a mechanistic framework distinguishing established from hypothesis-generating links; no formal systematic-review study selection or meta-analysis was performed. Results: Caffeine can increase urine output via renal mechanisms (adenosine receptor antagonism and natriuresis) and may lower bladder sensory thresholds. Because half-life is long and variable, afternoon intake can extend into sleep, potentially increasing awakenings and nocturnal voids. Human studies link colder indoor environments to nocturia/overactive bladder, and passive pre-bedtime heating is associated with fewer nocturnal voids. We propose that repeated nighttime cold may amplify caffeine-related diuresis and may shift urine production toward the night, while estradiol decline may heighten TRPM8-mediated cold sensory gain, potentially contributing to urgency/frequency flares. A testable 2 × 2 cold × caffeine framework can operationalize dose, timing, and metabolism, pairing voiding diaries and bedroom temperature sensing with copeptin profiling. Conclusions: Transitional menopause may represent a susceptibility window in which endocrine instability and estradiol decline could plausibly increase sensitivity to indoor cold exposure and caffeine intake, potentially contributing to nocturia and urgency. The hypothesis label ‘dual hormone suppression’ (attenuated nocturnal AVP signal plus estradiol decline) may provide a mechanistic substrate for cold-exacerbated nocturnal polyuria, while an estrogen–TRPM8 axis may amplify cold-evoked urgency. Potentially actionable candidates include chronobiological caffeine timing/management and low-burden thermal strategies; nevertheless, menopause-stage-specific epidemiologic and clinical evidence for a caffeine × cold interaction remains limited and several mechanistic links are extrapolated, so prospective diary- and biomarker-enabled studies and controlled trials are needed to validate mechanisms and refine cold-sensitive endotypes. Full article

Background: Red/blue- light-emitting diode (LED)-assisted withering provides a controllable spectral input to steer tea quality, yet metabolite-level evidence linking spectrum composition to quantitative taste phenotypes in white tea remains insufficient. Methods: Fresh leaves were withered under supplemental red/blue LEDs—S0, S1, S2, S3, S4, and S5—and the resulting white teas were evaluated by quantitative descriptive analysis (QDA), untargeted metabolomics, weighted gene co-expression network analysis (WGCNA), and high-performance liquid chromatography (HPLC) quantification of caffeine, gallic acid, and eight catechin monomers. Results: Red/blue-mixed spectrum enhanced the overall sensory quality relative to the incandescent lamp; S3 maximized sweetness and freshness, whereas S4 minimized bitterness and astringency and achieved the highest overall score. Untargeted metabolomics showed the largest deviation for S0 vs. S4. A total of 18 common metabolites were identified between the S0 and light-supplemented withering treatments, dominated by saccharides and related derivatives. WGCNA linked a saccharide-centered module to higher sweetness/freshness/smoothness and a lipid-oxylipin-centered module to stronger bitterness/astringency. HPLC independently confirmed that S4 contained the lowest catechins and caffeine, supporting its reduced bitter/astringent attributes. Conclusions: Overall, the application of mixed red-blue spectra offered a promising approach to enhancing the palatability of white tea by coordinately intensifying saccharide metabolism while simultaneously suppressing key bitter and astringent components. Our study provided a scientific basis for standardizing white tea processing to enhance sensory quality. Full article

Background: Long-haul travel and jet lag can disrupt athletes’ circadian, physiological, and performance systems, potentially impairing competition outcomes. This review aimed to study the effects of long-haul travel on athletes’ health and performance, differentiate travel fatigue from jet lag, and review mitigation strategies. Methods: A systematic narrative review was conducted following PRISMA 2020 guidelines. PubMed, Scopus, and Web of Science were searched for studies on jet lag, travel fatigue, and long-haul travel in athletes. Eligibility included studies reporting physiological, hemodynamic, or performance outcomes in athletes of any level and sex. Data were extracted on travel characteristics, interventions, physiological and performance markers, and risk of bias. Results: Overall, 284 records were identified, with 89 studies included. Travel directions were equally distributed between eastward and westward journeys, crossing 1–12 time zones. Interventions to mitigate travel effects were reported in 17 studies, primarily melatonin, caffeine, and light exposure. Common physiological changes included sleep disturbances (n = 36), body temperature alterations (n = 18), blood pressure changes, hormonal shifts (n = 9), heart rate variability (n = 4), and immune alterations (n = 4). Travel effects comprised fatigue (n = 25), sleep changes (n = 21), decreased physical performance (n = 18), mood changes (n = 15), and cognitive impairments (n = 9). Physical performance outcomes included anaerobic power (n = 18), strength (n = 14), velocity (n = 12), aerobic capacity (n = 10), coordination (n = 8), and reaction time (n = 7). Risk of bias was low in 49%, moderate in 17%, and high in 34% of studies. Conclusions: Long-haul travel negatively affects multiple physiological and performance domains in athletes, including sleep, hormonal balance, autonomic function, and physical performance. The magnitude of these effects seems to be influenced by travel direction, number of time zones crossed, and individual susceptibility. Eastward travel is generally associated with stronger circadian disruption and impaired aerobic capacity, coordination, and technical performance, whereas westward travel often induces greater fatigue and adversely affects team-sport outcomes. Monitoring key markers such as heart rate variability, sleep, and cortisol, combined with personalized strategies including circadian management, sleep hygiene, nutrition, recovery interventions, and training load adjustments, is essential to mitigate travel-related impairments and optimize performance. Full article

(1) Background: Medication-related problems (MRPs) are a significant burden on health care systems. Pharmacists play an important role in preventing and reducing MRPs through clinical review, education, and policy governance. This study analyzed pharmacist interventions within a 92-bed neonatal clinical care unit to better understand MRPs and guide targeted medication safety initiatives. (2) Methods: All pharmacist interventions documented in REDCap^® between 1 July 2022 and 30 June 2025 were analyzed identifying MRP incidence, types, and acceptability following interventions. (3) Results: A total of 873 pharmacist interventions were recorded during the study period. The most common MRPs were related to dosing errors (320/873, 36.7%), compliance with hospital policy (152/873, 17.4%), no indication apparent (106/873, 12.1%), drug interactions (66/873, 7.6%), and inadequate laboratory monitoring (40/873, 4.6%). Of these, 545/873, 62.4% were accepted by prescribers, while 228/873, 26.1% had unknown outcomes at the time of data entry. 343/873, 39.3% of interventions documented were from the Neonatal Intensive Care Unit, involving medications such as gentamicin (n = 46/343, 13.4%), benzylpenicillin (n = 37/343, 10.8%), caffeine (n = 34/343, 9.9%), parenteral nutrition (n = 23/343, 6.7%), and morphine (n = 16/343, 4.7%) and meropenem (n = 16/343, 4.7%)). (4) Conclusions: Regular analysis of pharmacist interventions provides valuable insights into local MRP trends and highlights opportunities for quality improvement and education. Full article

Background: Caffeine is widely used as an ergogenic aid to enhance strength performance; however, its effects on perceptual accuracy during submaximal force regulation remain unclear, particularly in multi-joint isometric tasks. This study examined whether caffeine ingestion influences maximal isometric force production and the accuracy of voluntary submaximal force estimation during complex isometric exercises. Methods: Seventeen recreationally trained participants completed a randomized, double-blind, placebo-controlled crossover study. Participants ingested either caffeine (4 mg·kg⁻¹ body mass) or a placebo before performing an isometric squat test (ISqT) and an isometric mid-thigh pull test (IMTP). Maximal voluntary contractions were assessed, followed by freely estimated submaximal efforts at 50% and 75% of perceived maximal force. Relative peak force and discrepancies between prescribed and exerted force (estimation error) were analyzed, with discrepancies calculated as the difference between exerted force and the prescribed target intensity. Results: Caffeine ingestion did not significantly affect relative peak force during maximal isometric efforts nor improve the accuracy of voluntary submaximal force estimation. Regardless of supplementation conditions, participants consistently misestimated submaximal efforts, tending to overproduce force, particularly at lower intensities. The IMTP showed a closer approximation to prescribed submaximal targets than the ISqT. Conclusions: Ingesting 4 mg·kg⁻¹ of caffeine does not enhance maximal isometric force output or perceptual accuracy during voluntary submaximal force regulation in multi-joint isometric tasks. Prescribing isometric intensity based solely on perceived effort may therefore be unreliable under these specific testing conditions, particularly at lower intensities. Full article

Objectives: To determine whether caffeine supplementation and its expectancy influence muscle strength (ST) and muscle endurance (ME) using a balanced-placebo design. Methods: Using a randomized, double-blind, balanced-placebo design, resistance-trained men (18–30 years; n = 16) participated in two assessment/familiarization visits (demographics; one repetition maximum (1RM) followed by four counterbalanced sessions: C/C (informed caffeine/used caffeine), P/C (informed placebo/used caffeine), C/P (informed caffeine/used placebo), P/P (informed placebo/used placebo). Caffeine dose was 5 mg/kg. Peak torque (PT) and maximum work (MW) were measured in the knee extensors at 0, 60, 180, and 300°/s, which was followed by ME testing (three sets of maximal repetitions using 60%1RM). Capillary blood lactate was measured after ME testing. Results: Caffeine increased PT only during static and 60°/s contractions (4%; p ≤ 0.003; d = 0.3 for both speeds), while MW increased across all speeds (4%; p < 0.001; d = 0.2). Caffeine did not increase ME (3%; p = 0.184; d = 0.1), but it did increase blood lactate levels (1.2 mmol/L; p < 0.001; d = 0.7). Caffeine expectation did not improve ST or ME, but increased blood lactate levels (0.7 mmol/L; p = 0.003; d = 0.4). Across ST and ME, responses to caffeine were markedly heterogeneous, with 50–88% of individuals considered responders (∆ > 0), and improvements in responders ranged from 1–16%. Conclusions: Caffeine significantly increased ST, despite ME increasing in 50% of participants, this was not significant. No placebo effect was observed in ST or ME, but it significantly increased lactate. Further research is necessary to elucidate the mechanisms behind this variability in the ME response, especially the role of fiber-type predominance. Full article

Background: Caffeine is an ergogenic aid shown to delay fatigue, increase arousal, and improve performance. Recommended doses are 3–6 mg/kg BM, although evidence supports lower doses (<3 mg/kg). Some conflicting results have highlighted that lower doses may still be ergogenic, and with new pouch and gum products, further research is warranted. Method: This study investigated the effects of novel low-dose caffeine products on muscular endurance, strength, and power. A repeated-measure, crossover design (pouch 80 mg, gum 80 mg, control gum 0 mg) was employed, recruiting nineteen participants (age 22.4 + 4.8 yrs; weight 72.8 + 16.9 kg; relative caffeine dose 1.1 mg/kg). Participants completed a battery of tests, including 60% 1 RM single leg press (LP) and shoulder press (SP) to exhaustion, counter-movement jump, and isometric mid-thigh pull, in addition to providing ratings of perceived exertion (RPE) during endurance tests. One-way repeated measures ANOVA was conducted on all measures associated with physical tasks, with a two-way repeated measures ANOVA conducted for RPE. Results: No significance was observed among conditions for physical tests. However, effect sizes, employing Cohen’s D classification, identified a moderate (d = 0.55) and small (d = 0.45) effect for the caffeine pouch compared to the placebo and caffeine gum for the LP respectively. Further, small effects for the pouch compared to the placebo were observed (d = 0.33) for the SP. Significant differences were produced for RPE during the LP (p = 0.022), with post hoc analysis identifying significant differences between the placebo vs. caffeine pouch (p = 0.032). Conclusion: Low-dose caffeine has the potential to produce meaningful effects on strength endurance, likely linked to caffeine mechanisms reducing RPE. Full article

This study focuses on the storage process of coffee beans, employing electron beam irradiation (EBI) to investigate the comprehensive effects of different irradiation doses on coffee beans and their storage process, including physicochemical indicators, microbial abundance, and flavor compounds. The results showed that a 2 kGy dose of EBI could effectively reduce the total number of bacteria, molds, and yeasts in green coffee beans (GCBs), while a dose of 4 kGy can completely inactivate the bacteria and maintain this effect for one month. Compared with the control sample that has not undergone processing by EBI (CK), the crude fat content of the irradiated samples decreased, accompanied by a significant increase in acid value. After 30 days of storage, compared with the CK-30 sample, EBI treatment significantly reduced both the moisture content and overall brightness value of GCB. The analysis of aroma compounds in roasted coffee beans (RCBs) revealed that substances related to Maillard reaction, caramelization reaction and sugar degradation, such as 2-Furanmethanol and acetic acid, changed in the irradiated samples, but had no significant effect on the characteristic components like caffeine and the aroma detected by the electronic nose. The obtained results provide a scientific basis for applying irradiation technology to the preservation of coffee beans. Full article

The development of sustainable vitrimers from bio-based sources addresses the need for high-performance recyclable materials. This research describes eugenol-derived epoxy vitrimers cross-linked with adipic acid as a curing agent, focusing on comparative effects of caffeine and zinc acetate as transesterification catalysts at 5 and 10% concentrations versus a non-catalyzed control. Both catalysts acted as curing accelerators, confirmed by FTIR and DSC analyses, revealing polyhydroxyester network formation through associative ester exchange enabling topological reorganization. Zinc acetate at 10% proved most efficient, achieving the lowest apparent activation energy (116.0 kJ/mol), highest crosslinking density (ν_e = 3.42 × 10⁻³ mol/cm³), improved thermal stability with unimodal degradation profile, and substantially reduced topology freezing transition temperature (T_v = 132 °C), confirming enhanced dynamic properties. Caffeine demonstrated catalytic activity, reducing apparent activation energy to 124.4 kJ/mol at 10% and promoting rapid epoxide conversion during initial curing at moderate temperatures. Although its catalytic efficiency is moderate compared to zinc acetate, its bio-based origin and non-toxic nature make it a promising green alternative for sustainable vitrimer applications. Results demonstrate that catalyst selection is crucial for tailoring curing kinetics, network structure, and final vitrimeric properties, providing key guidelines for designing advanced circular materials from bio-based precursors. Full article

Objective: This study assessed the ability of capsule formulations to improve the oral delivery and retain activity of an acid-sensitive enzyme during gastrointestinal transit. Methods: The dissolution characteristics of five capsule formulations—single DRcaps^® [DR], single Vcaps^® Plus [VCP], and three DUOCAP^® capsule-in-capsule combinations, DRcaps^® inside DRcaps^® (DR-in-DR), DRcaps^® inside Vcaps^® Plus (DR-in-VCP), and Vcaps^® Plus inside DRcaps^® (VCP-in-DR)—were evaluated in an in vitro simulation of a healthy human upper gastrointestinal tract under fasting and fed conditions using the Simulator of the Human Intestinal Microbial Ecosystem (SHIME)^® platform. Capsules contained caffeine as a marker of capsule dissolution, and pancreatin as an active ingredient for which activity was determined by the conversion of tributyrin. Readouts included visual capsule scoring, the analysis of caffeine release, and the quantification of tributyrin-to-butyrate conversion at the end of each gastrointestinal tract segment. Results: The single VCP capsules had a high level of caffeine release at the end of the stomach incubation with low butyrate recovery (16–21%), suggesting the rapid release and gastric degradation of the unprotected enzyme. The single DR, DR-in-VCP, and VCP-in-DR formulations showed caffeine release at the end of the duodenum and/or jejunum and had high butyrate recovery, ranging from 53% to 87%. The DR-in-DR formulation had the most delayed release, with incomplete caffeine release and low-to-moderate butyrate recovery (10–36%). Conclusions: Fast capsule dissolution led to the reduced enzymatic activity of the active ingredient, while delayed dissolution resulted in inadequate time for the enzymatic conversion of tributyrin to butyrate. These results highlight that capsule selection should align with the intended use and targeted nutrient delivery, with DUOCAP^® formulations being best suited for small intestinal (VCP-in-DR and DR-in-VCP) and colonic (DR-in-DR) delivery. Full article

Hypertension (HTN) remains a leading modifiable risk factor for cardiovascular disease, and non-pharmacological strategies combining exercise training with plant-derived bioactive supplementation are increasingly recognized as promising adjuncts for blood pressure (BP) management. This evidence-based review synthesizes findings from 31 clinical studies investigating selected plant-based supplements with the strongest available clinical evidence, namely beetroot juice (BRJ), green tea (GT), curcumin (CN), resveratrol (RSV), and garlic, administered alone or in combination with different exercise modalities across acute, short-term, and long-term interventions. Collectively, the evidence indicates that BRJ exerts the most consistent BP-lowering effects, particularly during aerobic training performed at ~50% heart rate reserve (HRR), or ~60% peak oxygen consumption (VO_2peak) in individuals with early-stage vascular dysfunction. CN and garlic also enhance exercise-induced BP reductions, especially in older or metabolically compromised populations. GT shows variable outcomes depending on caffeine content, exercise modality, and participant health status, while RSV provides modest vascular support, often contingent on concurrent training. Mechanistically, these botanicals and exercise converge on key vascular-regulatory pathways, including enhanced nitric oxide (NO) bioavailability, reduced oxidative stress and inflammation, attenuated renin–angiotensin–aldosterone system (RAAS) and sympathetic activity, and improved mitochondrial function through Sirtuin 1 (SIRT1)/AMP-activated protein kinase (AMPK) signaling. Together, these integrated mechanisms improve endothelial function, lower vascular resistance, and ultimately reduce BP. From a translational standpoint, combining exercise with targeted plant-based supplementation offers a safe, accessible, and physiologically synergistic strategy for BP control in clinical populations. Future research should define optimal dosing, timing relative to exercise, and population-specific efficacy to inform precision-based, integrative interventions for HTN management. Full article

Caffeine is one of the most well-known biologically active compounds in coffee beans, and its content largely determines the taste and stimulating properties of the drink. However, the amount of caffeine in beans can vary significantly depending on growing conditions, even within the same coffee variety. The growing global demand for coffee and the current market dynamics emphasize the necessity to investigate how the origin of coffee beans influences beverage quality. Arabica beans, particularly the Red Bourbon variety, are known to exhibit variations in chemical composition, sensory characteristics, and technological behavior depending on their cultivation environment. The study aimed to evaluate the physicochemical and sensory properties of Arabica Red Bourbon beans sourced from distinct geographic regions, considering factors such as altitude and local environmental conditions. The sensory characteristics of the resulting beverages were evaluated using the capping method, and water activity, density, moisture content, color, pH, extractivity and caffeine content were determined. Roasted bean color ranged from 61.4 to 62.5, while ground coffee color was 72.5–75.4. Moisture content was highest in Col and R (3.4%) and lowest in Con (3.1%). The greatest moisture loss during roasting occurred in S and R (13.4%). Water activity decreased from 0.50–0.56 in green beans to 0.18–0.30 post-roasting. Extraction yield ranged from 20.03 to 21.21%, and total dissolved solids (TDS) varied at 1.23–1.30%. The least acidic sample was S (pH 5.04). Colombian beans contained unusually high caffeine. The conducted research confirmed that the geographical origin of Arabica Red Bourbon beans significantly impacts their physicochemical and sensory attributes. Variations in moisture, acidity, and caffeine content were observed among the samples, despite a consistent roasting profile. Full article