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PubMed2026

Proteomic characterization of the acquired enamel pellicle under acidic challenges at early and mature formation stages.

OBJECTIVES: This study aimed to characterize acquired enamel pellicle (AEP) proteomic changes after exposure to citric acid (CA) and hydrochloric acid (HCl) under different pellicle formation times (3 and 120 min) in the same volunteers. DESIGN: Nine healthy volunteers participated in this randomized crossover in vivo study. The AEP was allowed to form for 3 or 120 min and subsequently exposed for 10 s to deionized water (control), 1% CA (pH 2.5), or 0.01 M HCl (pH 2.0). Pellicle samples were collected, followed by protein extraction, tryptic digestion, and analysis by nanoliquid chromatography (nanoLC) coupled to mass spectrometry (MS) with MSE (data-independent acquisition; nanoLC-MSᴱ). Label-free quantitative proteomics were performed for relative quantification using t-test (p < 0.05). RESULTS: At 120 min, CA exposure markedly reduced several typical AEP proteins, especially acidic proline-rich proteins (PRPs). Conversely, basic PRPs were upregulated, suggesting acid-resistance protein signature. At 3 min, basal-layer proteins (PRPs, cystatins, histatins and mucins) were more abundant. Hemoglobins increased 6-8-fold (up to 150-fold in 3 min control), suggesting association with early pellicle formation and an acid-resistant protein signature. CA exposures for 120 min also upregulated typical AEP proteins (PRPs, mucins, cystatins, immunoglobulins), while HCl exposure depleted albumins and lactotransferrin. CONCLUSION: Intrinsic and extrinsic acids induce distinct proteomic signatures in the AEP. Hemoglobin and PRPs appear consistently enriched in the early pellicle layer, reflecting an initial acid-resistant protein signature. These findings provide new insights into the molecular remodeling of the AEP following intrinsic and extrinsic acid exposure, highlighting proteins potentially involved in early-stage pellicle formation.

Humans↗

PubMed2026

Comfort and Usability of Digital Versus Conventional Custom-Fit Mouthguards: A Randomized Clinical Trial.

BACKGROUND/OBJECTIVES: The use of mouthguards protects teeth and the supporting tissues against impacts. Digital impressions and 3D-printed models can reduce manufacturing steps and minimize discomfort. This study evaluated the fit, comfort, and usability of custom-made mouthguards, obtained by conventional and digital workflow, in amateur athletes. MATERIALS AND METHODS: Amateur athletes were recruited for this randomized, double-blind, crossover clinical study. Each participant received two 4-mm-thick custom-fit mouthguards made of ethylene vinyl acetate (EVA) sheets using two protocols: conventional impression using alginate to produce dental stone cast (CMP) and intraoral digital scanning to produce 3D-printed resin models (DMP). Each mouthguard was worn during all training and matches over 3 months. The order of mouthguard use was randomly assigned. Patient satisfaction with the impression protocol and mouthguard use, model accuracy, and mouthguard fit were assessed. RESULTS: Overall, 46 participants completed the study. The DMP protocol required less execution time (p = 0.023), caused less discomfort (p = 0.018), anxiety (p = 0.008), nausea (p = 0.027), difficulty breathing (p < 0.001), and unpleasant taste (p = 0.006) compared to the CMP protocol. The pain (p = 0.971) perceived by the participants was similar in both impression protocols. The CMP-mouthguards were considered to be better fitting by the majority of participants (p = 0.027). Between-group comparisons revealed that DMP-mouthguard caused less discomfort immediately postadaptation (p = 0.034), with no significant differences observed at 30 or 90 days. CONCLUSIONS: The digital workflow demonstrated to be efficient in the fabrication of mouthguards. Digital impression was more comfortable, requiring less execution time, with more accurate printed models and produced mouthguards with reported comfort and fit levels similar to those manufactured conventionally.

Humans↗

PubMed2026

Effects of a programmed reflexology therapy on sleep quality, insomnia, and fatigue among individuals with poor sleep quality: evidence for autonomic nervous system modulation.

Poor sleep quality is closely associated with autonomic dysregulation and increased risks of cardiovascular, metabolic, and mental disorders. Foot reflexology is a widely used complementary therapy; however, its physiological mechanisms and comparative efficacy remain insufficiently explored. This study aimed to compare the effects of manual reflexology treatment (MRT) and foot massage equipment (FEM) on autonomic nervous system function, sleep quality, insomnia severity, and fatigue in adults with poor sleep quality. Using a randomized crossover design, 32 participants with poor sleep quality received MRT and FEM interventions for 6 weeks each (once weekly, 30-40 min/session). Heart rate (HR), blood pressure, and heart rate variability (HRV; time- and frequency-domain indices) were assessed at weeks 1 and 6 before and after each intervention. Subjective outcomes included the Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), and Fatigue Assessment Scale (FAS). Following MRT, participants demonstrated significantly greater reductions in global PSQI scores and all PSQI components compared with FEM. MRT also resulted in larger improvements in insomnia severity and both mental and physical fatigue. In contrast, FEM primarily improved physical fatigue. Physiologically, MRT induced an immediate decrease in HR and significant increases in HRV time-domain indices (SDNN, RMSSD, pNN50), which were sustained after 6 weeks. Frequency-domain analysis further revealed reduced LF, increased HF, and a lower LF/HF ratio, indicating enhanced parasympathetic activity and cumulative autonomic modulation. In conclusion, programmed manual reflexology, delivered according to the TIDieR framework, is more effective than mechanical foot massage in improving autonomic balance, sleep quality, insomnia severity, and fatigue in individuals with poor sleep quality. These findings support MRT as a feasible and evidence-based non-pharmacological complementary intervention for sleep health promotion. TRIAL REGISTRATION: clinicaltrials.gov; NCT Number: NCT07402460; Registered 3 February 2026.

Adult↗

PubMed2026

Effect of Food on Balcinrenone/Dapagliflozin Pharmacokinetics and the Pharmacokinetics of Balcinrenone When Dosed with a P-gp Inhibitor.

Balcinrenone (AZD9977) is a novel selective non-steroidal mineralocorticoid receptor antagonist with a distinct mode of action being developed as a fixed-dose combination with the sodium-glucose cotransporter-2 inhibitor dapagliflozin for the treatment of heart failure with impaired kidney function, and chronic kidney disease. In this Phase 1 randomized open-label three-way crossover study we investigated the effect of food on balcinrenone/dapagliflozin pharmacokinetics, and the pharmacokinetics of balcinrenone when dosed with a P-glycoprotein (P-gp) inhibitor. Fourteen healthy participants were administered an oral capsule of balcinrenone/dapagliflozin 40 mg/10 mg in three dosing periods: fasted (reference), fed (high-fat, high-calorie meal) and with a P-gp inhibitor (quinidine 300 mg × 2). Balcinrenone exposure was comparable in the fed and fasted states (geometric mean ratios [GMRs] [90% CI]: maximum plasma concentration [Cmax] 1.05 [0.88, 1.25]; area under the plasma concentration-time curve from time 0 to infinity [AUCinf] 1.12 [1.06, 1.19]). In the fed state, dapagliflozin AUCinf was comparable to the fasted state (GMR [90% CI] 1.05 [1.01, 1.09]), whereas Cmax was decreased (GMR [90% CI] 0.59 [0.51, 0.69]), in line with previous dapagliflozin food interaction studies. Co-administration with quinidine increased balcinrenone exposure: GMRs (90% CI) 1.48 (1.24, 1.76) and 1.24 (1.17, 1.31) for Cmax and AUCinf, respectively, but AUC fold increase was <2, the level used for classification of sensitive P-gp substrates. All interventions were well tolerated. In conclusion, this study supports dosing of balcinrenone/dapagliflozin without regard to food. Balcinrenone is not considered a sensitive P-gp substrate. No P-gp based dosing precautions are warranted based on this study.

Adult↗

PubMed2026

Pulmonary artery catheters or central venous catheters for cardiac surgery: the PUMA Pilot randomised clinical trial.

INTRODUCTION: Pulmonary artery catheters are used widely in cardiac surgery despite observed associations with worse outcomes and guidelines that recommend against their routine use. No adequately powered randomised trials are available. METHODS: The PUMA Pilot was a multicentre, randomised, parallel assignment, open-label, pilot and feasibility trial conducted at three tertiary cardiac surgery centres. Eligible patients were adults undergoing coronary artery bypass grafting, aortic valve replacement or surgery on the aortic root or ascending aorta with or without aortic valve replacement, with a predicted surgical mortality of < 2%. Patients were allocated randomly to receive a pulmonary artery catheter or a central venous catheter inserted immediately before surgery. The primary feasibility outcome was protocol compliance, defined as receiving the assigned intervention without crossover. Secondary feasibility outcomes were eligibility rate; recruitment proportion and rate; data completeness; and rate of clinician refusal. RESULTS: We screened 480 patients and 206 (43%) were eligible; 150/203 (74%) approached provided informed consent. Three of 206 (1%) eligible patients were not included due to clinician refusal. Of 149 patients who were randomised, 76 were assigned to the pulmonary artery catheter group and 73 to the central venous catheter group. For the primary feasibility outcome, 147 patients (99%) received the allocated intervention. Data were complete for 144 (97%) patients. Median (IQR [range]) days alive and at home at 30 days was 23.7 (21.9-24.7 [7.0-26.0]) in the pulmonary artery catheter group and 22.9 (20.8-23.9 [8.6-25.8]) in the central venous catheter group. Acute kidney injury occurred in 26/76 (34%) patients in the pulmonary artery catheter group and 14/73 (19%) in the central venous catheter group. DISCUSSION: A randomised trial of pulmonary artery catheters compared with central venous catheters in low-risk cardiac surgery is feasible. Such a trial would address significant practice variability and inform international guidelines.

Humans↗

PubMed2026

Characterizing Submental Neuromuscular Activity of Swallowing Rehabilitation: An Electromyographic Evaluation of Rehabilitative Maneuvers in Healthy Adults.

PURPOSE: The effortful swallow (ES), the Mendelsohn maneuver (MM), and isometric tongue presses (TPs) are widely used swallowing maneuvers/exercises to improve elements of swallowing, such as muscle strength and biomechanics. However, the underlying neuromuscular mechanisms of these exercises remain unclear, potentially limiting our ability to specify treatment targets and improve treatment efficacy. This study aimed to compare submental neuromuscular activation patterns during the ES, MM, TPs, and typical swallows in healthy young and older adults. METHOD: As part of a larger randomized crossover validation study, 60 healthy adults (30 young and 30 older) completed typical swallows and three maneuvers using a wearable submental surface electromyographic (sEMG) system (i-Phagia). Outcome variables included (a) normalized mean sEMG amplitude and (b) time to peak sEMG amplitude. Linear mixed models were used to examine effects of task, age, and sex on both outcomes. RESULTS: Normalized mean amplitude was significantly different across tasks. Post hoc pairwise comparisons confirmed that all three maneuvers produced higher normalized mean sEMG amplitude than typical swallows, with the ES eliciting the highest amplitude across age groups. Time to peak amplitude differed significantly across tasks, with typical swallows requiring the shortest time to reach peak amplitude, followed by the ES, MM, and TP. CONCLUSIONS: The ES required the highest neuromuscular effort with the shortest time to reach peak amplitude, suggesting its potential for targeting submental muscle power. Typical swallows required the least neuromuscular effort with the shortest time to reach peak amplitude, suggesting their potential for training submental muscle speed. The MM and TP may also improve submental muscle strength; however, given their temporal requirements (longer durations), they may be more beneficial for targeting coordination and endurance, though more research in this area is warranted. These findings underscore the importance of task-specific neuromuscular profiling to inform mechanism-based swallowing rehabilitation. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.32948549.

Humans↗

PubMed2026

Effects of antidepressant administration on physical performance and perceived exertion in athletes: systematic review and meta-analysis.

INTRODUCTION: Antidepressants are commonly prescribed in athletes with depressive disorders, yet their potential effects on physical performance and perceived exertion remain unclear, and existing evidence is limited and inconsistent. AIM: This systematic review and meta-analysis aimed to evaluate the effects of antidepressant use on objective physical performance and perceived exertion in athletes. METHOD: A systematic literature search was conducted in PubMed, the Cochrane Library, Web of Science, and SPORTDiscus through March 2025. Eligible studies were randomised controlled trials (RCTs) published in English that enrolled elite, competitive, or recreational athletes; compared antidepressant administration with placebo or no treatment; and reported at least one objective or subjective performance-related outcome. Meta-analyses were performed using random-effects models, and pooled mean differences with 95% confidence intervals (CI) were calculated. This systematic review and meta-analysis was registered in PROSPERO (CRD420251123740). RESULTS: Ten crossover RCTs involving 99 male athletes were included. Interventions included a norepinephrine reuptake inhibitor (reboxetine), a norepinephrine-dopamine reuptake inhibitor (bupropion), and selective serotonin reuptake inhibitors (fluoxetine or paroxetine). Acute antidepressant administration was associated with a small increase in rating of perceived exertion (RPE; mean difference 0.52 points on the Borg 6-20 scale, 95% CI 0.01-1.04; p < 0.05). No significant overall effects were observed for time-trial performance, mean power output, heart rate or blood lactate. However, subgroup analyses showed that reboxetine significantly impaired time-trial performance (mean difference 3.62 min, 95% CI 0.18-7.06; p < 0.05) and reduced mean power output (mean difference - 19.97 W, 95% CI - 36.87 to - 3.06; p < 0.05). CONCLUSION: Short-term antidepressant administration in athletes was associated with a small increase in perceived exertion, without consistent impairment in objective physical performance. As the current evidence derives exclusively from male athletes and acute exposure, further research should clarify its relevance to female athletes and to longer-term antidepressant treatment in athletes with depressive disorders.

Humans↗

PubMed2026

Acute Performance, Mechanical and Thermal Effects of Isometric Conditioning Versus Standardized Volleyball Pre-Training Activation in Highly Trained Male Players.

This study compared acute performance, neuromuscular, and thermal responses to a maximal isometric conditioning activity (ICA) versus a standardized volleyball pre-training activation (VPA) in highly trained male volleyball players, and to explore putative mechanisms underpinning post-activation performance enhancement (PAPE) considering training load. In a randomized crossover, 14 men (27 ± 3 y) completed two sessions: VPA (mobility/plyometric drills; 9 min), and ICA comprising 3×5×3-s maximal isometric back-squat contractions (knee angle 120°; 3-min inter-set rest). Countermovement jump (CMJ) height (primary), relative peak power (PP), RSImod, and contraction time (CT) were recorded pre and 3, 6, 9, and 12 min post. Rectus femoris muscle viscoelastic properties and skin surface temperature (SST) were assessed at matched time points. Analyses used repeated-measures ANOVA, responder analysis, correlations, and regression. Period×Sequence interactions favored ICA for CMJ and PP when delivered in Period 2 (lower training volume): ∆CMJ was higher under ICA versus VPA (p = 0.005, d = 1.20); PP likewise greater (p = 0.026, ηp2 = 0.35). ICA yielded more beneficial responders than VPA (9/14 vs 1/14; McNemar exact p = 0.021). In Period 2, reductions in rectus femoris muscle stiffness independently predicted CMJ gains (β_std = -0.495, p = 0.005), whereas SST changes did not (p = 0.974). RSImod and CT showed no differences. A brief, high-effort isometric squat protocol was associated with superior acute improvements in jump performance compared with a standard volleyball warm-up, but this advantage emerged specifically when the preceding training volume was reduced (Period 2), suggesting that residual fatigue from training may reduce the effects of PAPE. Gains align with neuro-mechanical rather than thermal mechanisms, supporting ICA as a practical, equipment-minimal priming strategy for elite volleyball.

Humans↗

PubMed2026

The effect of drysuit diving in warm water on body temperature and post immersion orthostatic hypotension.

INTRODUCTION: Warm-water diving can limit heat dissipation, particularly when performed in fully encapsulating protective gear, leading to substantial thermal and cardiovascular strain that may impair diver safety. Following immersion, removal of hydrostatic support combined with heat-induced vasodilation may reduce central blood volume and increase susceptibility to orthostatic intolerance during egress and recovery. The extent to which this thermal strain impairs post-immersion orthostatic tolerance remains unknown. METHODS: Four randomised, crossover immersion trials were conducted at 28°C, 33°C, 38°C without precooling (38°C), and 38°C with precooling (38°C + Cool), with subjects wearing fully encapsulating dive gear. Subjects walked for up to 60 minutes at approximately 50% of O2max heart rate (HR) or until core temperature (Tc) reached 38.5°C, or they voluntarily stopped. Tc, HR, and perceptual measures were recorded every 10 minutes. Orthostatic tolerance was assessed after immersion via a 70° head-up tilt test. RESULTS: Eight healthy adults completed all aspects of the study. Tc and HR were higher during both 38°C conditions compared with 28°C and 33°C (all P < 0.01) with no differences between 38°C and 38°C + Cool. Sweat loss exceeded 1.2 (SD 0.67) L⋅h-1 in both 38°C conditions compared with ≤ 0.3 (0.32) L⋅h-1 at 28°C and 33°C (P < 0.01). Survival analysis showed orthostatic tolerance decreased with increasing thermal stress (log-rank P = 0.027; trend P = 0.003). Precooling did not reduce peak Tc or HR, nor did it improve tolerance time in 38°C water. CONCLUSIONS: Encapsulated warm-water diving causes heat stress and cardiovascular strain that persists after immersion, impairing orthostatic tolerance. Precooling does not significantly reduce these outcomes.

Humans↗

PubMed2026

Effects of carbohydrate mouth rinse on psychophysiological responses, kinematic variables and technical actions during small-sided soccer games.

BACKGROUND: This study investigated the effects of carbohydrate mouth rinsing (CHOMR) on various psychophysiological, kinematic, and technical actions during 4-a-side small-sided soccer games (SSGs). METHODS: In a randomized, crossover, double-blind design, 16 young male soccer players (age: 15 ± 1 years; height: 172.6 ± 7.0 cm; body mass: 57.8 ± 7.9 kg) participated in two 4-a-side SSGs separated by one week following either CHOMR or placebo (PLA). During each SSGs, heart rate (HRmean, %HR, and HRmax), rating of perceived exertion (RPE), enjoyment, visual analogue scale (VAS) to perceived mental fatigue, mood states, total distance (TD), high-speed running distance (HSRD), average metabolic power (AMP), high metabolic load distance (HMLD), sprint distance (SD), acceleration (ACC), deceleration (DEC), and technical actions (e.g. passing, tackling, shooting, and interceptions) were assessed. RESULTS: Compared with PLA, CHOMR resulted in significantly higher RPE (p = 0.025, g = 0.86) and significantly lower VAS scores (p = 0.010, g = -0.71). In addition, the CHOMR condition showed significantly higher values for interceptions, successful tackles, unsuccessful tackles, unsuccessful shots, and goals (p < 0.05, g = 0.96-2.02), whereas block values were significantly higher in the PLA condition. There were no statistically significant differences in HRmean, %HR, HRmax, enjoyment, TD, HSRD, AMP, HMLD, SD, ACC, DEC, successful passes, unsuccessful passes, successful shots, or mood states between the conditions (p > 0.05). CONCLUSION: The current study findings suggest that CHOMR may enhance selected technical actions and lower VAS scores during 4-a-side SSGs, although it was also associated with higher RPE and did not alter the kinematic responses. In conclusion, CHOMR was associated with higher RPE, lower mental fatigue, and selective improvements in technical actions, with no significant effects on kinematic variables or HR.

Humans↗

PubMed2026

The impact of acute sleep fragmentation on muscle blood flow responses to handgrip exercise.

Sleep fragmentation is reported to impair resting vascular function. The aim of this study was to test the hypothesis that acute sleep fragmentation would impair muscle blood flow during exercise. Twenty adults (10 females and 10 males) participated in a randomized crossover study that included one night of habitual sleep and one night of fragmented sleep. Sleep was assessed at home using wrist actigraphy. Arousals from sleep were increased by an audio alarm sounding every 30 min. The morning following each sleep condition, participants performed single handgrip contractions and rhythmic handgrip exercise at 15%, 30%, and 45% MVC. Forearm blood flow (FBF) was measured using Doppler ultrasound. Nightly awakenings and wake after sleep onset significantly increased by 18% and 43%, respectively, after fragmented sleep, leading to lower sleep duration (P < 0.001). Peak FBF and total hyperemic responses following single contractions were similar between sleep conditions (all P > 0.05). During rhythmic handgrip exercise, brachial artery dilation was reduced after fragmented sleep (main effect: 5.5 ± 4.8 vs. 3.3 ± 3.7%; P = 0.01), leading to a lower FBF response to rhythmic exercise (main effect: 122 ± 58 vs. 110 ± 56 mL/min; P = 0.04). Endothelial sensitivity to shear rate was similar between sleep conditions (habitual vs. fragmented: 0.039 ± 0.024 vs. 0.042 ± 0.031%/s-1; P = 0.77). In summary, acute sleep fragmentation decreases skeletal muscle blood flow during exercise. This finding suggests that blunted oxygen delivery may be a contributing factor for exercise performance deficits after disturbed sleep.NEW & NOTEWORTHY We demonstrate that one night of fragmented sleep decreases steady-state blood flow and vascular conductance during low- to moderate-intensity handgrip exercise. This impairment was not due to an impaired rapid vasodilation to single contractions nor altered endothelial sensitivity to shear rate as these variables were unchanged after acute sleep fragmentation. These results reveal a negative impact of disrupted sleep on the steady-state muscle vasodilatory response to rhythmic contractions.

Humans↗

PubMed2026

A study on the differences in recovery effects of different types of nutritional supplements on competitive performance of esports athletes under mental fatigue.

BACKGROUND: To compare the effects of different nutritional supplements on the recovery of core competitive performance abilities in esports athletes following mental fatigue and to observe changes in the autonomic nervous system during recovery after nutritional supplementation by monitoring heart rate variability (HRV). METHODS: A randomized crossover within-subject controlled experimental design was adopted, including nutritional supplement type (caffeine, nitrate, Ginkgo biloba extract, catechins, placebo) × mental fatigue state (initial, fatigued, post-supplementation). Twenty high-level first-person shooter (FPS) esports athletes were recruited. Mental fatigue was induced using a Stroop task. After ingesting the different supplements and resting for 60 minutes, the participants completed assessments of shooting accuracy, shooting stability, spatial localization, and multitasking ability using the KovaaK's simulation trainer. HRV indices were also recorded to evaluate changes in autonomic regulation. RESULTS: For shooting accuracy, compared with the placebo condition, all four supplements significantly improved shooting accuracy scores following mental fatigue (all p < 0.05); however, no significant differences were observed among the effects of the different supplements. For shooting stability, caffeine, nitrate, and catechins produced significant recovery effects on shooting stability (all p  < 0.05); however, no significant differences were observed among the effects of these three supplements. For spatial localization and multitasking ability, the improvements in these two abilities in the post-supplementation state may have resulted from natural recovery, and none of the four nutritional supplements demonstrated a significant recovery effect. The HRV results showed that indices including RMSSD and SDNN changed under some supplement conditions. CONCLUSIONS: Mental fatigue significantly reduced the competitive performance of esports athletes. Four types of nutritional supplements all promoted the recovery of shooting accuracy, while caffeine, nitrate, and catechins promoted the recovery of shooting stability. However, no additional recovery advantages of the nutritional supplements over placebo were identified for spatial localization or multitasking ability. Changes in HRV may reflect changes in autonomic regulation during recovery, but further research is still warranted.

Humans↗

PubMed2026

Application of 13C MRS demonstrates carbohydrate feeding spares muscle but not liver glycogen utilization during high-intensity interval exercise.

We examined liver and muscle glycogen utilization during high-intensity interval cycling, and the impact of carbohydrate (CHO) feeding, using noninvasive 13C magnetic resonance spectroscopy (MRS). Following 24 h of standardized dietary intake, nine male cyclists completed 8 × 5-min intervals (1-min recovery), ingesting either placebo (PLA), 60 g maltodextrin (CHO), or 60 g maltodextrin plus caffeine, taurine, l-theanine, l-citrulline, and citicoline (CHO+) in a randomized crossover design. 13C MRS and 1H imaging were performed pre- and postexercise to determine liver and muscle glycogen and liver volume, respectively. Liver glycogen utilization was not significantly different between trials (P = 0.101) despite lower postexercise plasma glucagon concentrations in CHO and CHO+ (P = 0.001). In contrast, muscle glycogen utilization was significantly lower (∼40%) with CHO feeding compared with PLA (P = 0.006), yet this sparing effect was not evident with CHO+ (P = 0.073) in accordance with a higher mean power output during the late intervals (+2.8%, P = 0.046). Plasma glucose was comparable between trials (P = 0.175), whereas plasma lactate was higher in CHO+ versus CHO (P = 0.003), alongside lower blood bicarbonate (P = 0.005), base excess (P < 0.001), and total CO2 (P = 0.004). These findings demonstrate preferential use of skeletal muscle glycogen during high-intensity interval training (HIIT), which is attenuated under conditions of CHO feeding. This sparing effect is, however, not evident with the coingestion of a caffeine-containing multi-ingredient blend, potentially due to an increased capacity to sustain higher power outputs resulting in greater glycogen utilization.NEW & NOTEWORTHY Using 13C MRS, we provide data demonstrating preferential use of skeletal muscle glycogen during HIIT. Furthermore, data show muscle glycogen utilization is attenuated with CHO feeding, yet sparing is not evident when coingesting a caffeine-containing formulation, potentially reflecting increased capacity to perform more total work rather than a direct metabolic effect of caffeine. In contrast, liver glycogen utilization was not significantly different with CHO feeding despite a modest reduction of ∼5 g versus placebo.

Male↗

PubMed2026

Does co-administration of cannabidiol (CBD) influence the plasma availability of delta-9-tetrahydrocannabinol (THC) and its active metabolite in humans? A systematic review and meta-analysis.

BACKGROUND: Research on the pharmacokinetic influence of cannabidiol (CBD) on delta-9-tetrahydrocannabinol (THC) has produced equivocal results. METHODS: We conducted a systematic search following PRISMA guidelines (last search: 24th November 2025, PROSPERO: CRD42023480695). Included studies were acute dosing trials that administered a) a single, fixed dose of THC and b) a matched dose of THC co-administered with CBD. Our objective was to investigate between-group differences in the Cmax, AUCt and AUCinf of circulating THC and its active metabolite, 11-hydroxy-THC (11-OH-THC). Hedges' g and ratio of means (RoM) were pooled from random-effects meta-analyses. The dose-effects of CBD and THC on Hedges' g were explored using meta-regression. Risk of bias was assessed using the Cochrane Collaboration tool RoB 2. RESULTS: 14 studies were included (12 crossover, two parallel group; seven oral administration, five inhalation, one IV, one mixed IV and oral; total participants: 341). In meta-analyses, average AUCt of THC was significantly higher in CBD co-administration study arms versus THC-only (Hedges' g= 0.526, 95%CI= 0.222-0.830), with very low certainty evidence. Both Cmax and AUCt of 11-OH-THC were significantly higher in CBD co-administration study arms (Cmax: g= 0.428, 0.115-0.741; AUCt: g= 0.692, 0.284-1.099), both with medium certainty evidence. In meta-regression analyses, CBD demonstrated dose effects on the Hedges' g of the Cmax and AUCt of 11-OH-THC (P < 0.05), but not THC levels. CONCLUSIONS: Cannabis users and prescribers of cannabinoid-based products should be made aware of the potential for drug-drug pharmacokinetic interactions between CBD and THC.

Humans↗

PubMed2026

Characteristics of post-exercise responders versus non-responders following aerobic or isometric exercise in physically inactive adults of African and South Asian descent with high-normal blood pressure or grade I hypertension.

OBJECTIVE: To investigate interindividual variability in post-exercise hypotension (PEH) and to characterise cardiovascular and autonomic differences between responders and non-responders following aerobic and isometric exercise in adults of African and South Asian descent with elevated blood pressure (BP). METHODS: Physically inactive adults of African and South Asian descent living in Suriname (18-65 years) with high-normal BP or grade I hypertension participated in a randomised controlled crossover trial. In this randomised cross-over trial, 47 adults (50.1 ± 10.8 years; 38% male) with high-normal blood pressure or grade I hypertension completed three conditions: aerobic exercise (30 min at 40-60% heart rate reserve), isometric handgrip exercise, and a non-exercise control. Ambulatory BP was assessed over 24 h. PEH was defined as the net effect: (post-exercise - pre-exercise) - (post-control - pre-control). Participants were classified as responders if daytime BP decreased ≥5 mmHg. Arterial stiffness, cardiac, and autonomic parameters were assessed. RESULTS: Following aerobic exercise, 46% of participants were classified as systolic responders compared with 28% after isometric exercise. No baseline differences were observed in demographic or clinical characteristics between responders and non-responders, suggesting that PEH variability may reflect underlying physiological rather than clinical differences. Aerobic responders demonstrated greater reductions in aortic augmentation index (-19.4% vs. -10.9%, p = 0.05), larger increases in stroke volume (+8.1 vs. -5.3 mL, p = 0.05) and cardiac output (+1.54 ± 1.89 vs. +0.58 ± 1.60 L/min, p = 0.009), and more favourable autonomic recovery. Among all variables, only the change in cardiac output was associated with PEH magnitude (r = -0.46, p = 0.006). No consistent physiological differences were observed following isometric exercise. CONCLUSION: PEH following aerobic exercise is characterised by a distinct responder phenotype associated with greater reductions in aortic augmentation index and favourable cardiac adaptations. These findings highlight substantial interindividual variability in BP responses and support the need for individualised exercise strategies in hypertension management.

Adolescent↗

PubMed2026

Effects of an actuated ankle exoskeleton on walking stability in healthy adults: a controlled laboratory study.

BACKGROUND: Ankle exoskeletons are widely used to reduce the metabolic cost of walking, yet their effects on walking stability during unperturbed gait remain insufficiently understood. Walking stability can be characterized using complementary measures that capture stride-to-stride variability, global temporal organization, and local dynamic stability. Understanding how walking with an actuated ankle exoskeleton system influences these different aspects of gait stability is essential for the safe design and control of wearable robotic devices. METHODS: Eighteen healthy adults walked on a treadmill at a constant speed (1.1 m/s) with and without an actuated bilateral ankle exoskeleton in a randomized crossover design. Spatiotemporal variability was quantified using coefficients of variation (CoV) of stride length, step width, and stance ratio. Global gait stability was assessed using detrended fluctuation analysis of stride time. Local dynamic stability was evaluated using maximum Lyapunov exponent calculated for the trunk, hip, upper leg, lower leg, and foot. Paired-samples two-sided t-tests were used to compare conditions. RESULTS: Walking with the ankle exoskeleton resulted in increased stride-to-stride spatiotemporal variability, reflected by higher CoV values for stride length (p < 0.001) and stance ratio (p = 0.005), while mean stride length and step width remained unchanged. Mean stance ratio was reduced in the exoskeleton condition (p < 0.001). Global gait stability did not differ between conditions, indicating preserved long-range temporal gait organization. Local dynamic stability increased at the lower leg (p < 0.001) and foot (p = 0.019) when walking with the exoskeleton. CONCLUSIONS: Walking with the actuated ankle exoskeleton alters gait control across multiple levels during steady walking. While stride-to-stride variability in stride length and stance ratio increased, global gait stability remained unchanged. Local dynamic stability was increased at the lower leg and foot, suggesting segment-specific effects of ankle-level assistance close to the assisted joint. However, these findings should be interpreted as the combined effect of wearing the exoskeleton and receiving active assistance, rather than the isolated effect of plantarflexion assistance. These results provide insight for the design and control of ankle exoskeletons with respect to stability-related effects during walking.

Humans↗

PubMed2026

Effects of short-bout accumulated exercise on postprandial metabolism in adults: A systematic review and meta-analysis.

OBJECTIVE: To systematically evaluate the acute effects of short-bout accumulated exercise (SBAE) interrupting prolonged sedentary behaviour on postprandial glucose, insulin, and triglycerides in adults. METHODS: Systematic searches in PubMed, Web of Science, Embase, Cochrane Library, CINAHL, SPORTDiscus, and CNKI (inception to 10 December 2025) identified randomised crossover trials comparing SBAE (≤10 min/bout, inter-bout interval ≥30 min or adequate recovery) with continuous sedentary behaviour. Outcomes included postprandial glucose, insulin, and triglyceride AUCs. Standardised mean differences (SMD) were pooled using random-effects models. RESULTS: Thirty-one publications reporting data from 29 independent cohorts involving 573 unique participants (mean age 47.8 ± 20.3 years; 47.5% female; mean BMI 29.0 ± 5.1 kg/m²) were included. Compared with continuous sedentary behaviour, SBAE significantly reduced glucose AUC (SMD = -0.53, 95% CI: -0.71 to -0.34, P < 0.001) and insulin AUC (SMD = -0.58, 95% CI: -0.85 to -0.31, P < 0.001), but not triglyceride AUC (SMD = -0.17, 95% CI: -0.48 to 0.15, P = 0.306).Exploratory subgroup analyses showed statistically significant reductions in glucose and insulin for walking and for inter-bout intervals < 60 min, but not for standing alone or intervals ≥ 60 min. A statistically significant insulin-lowering effect was observed in obese individuals. CONCLUSION: SBAE acutely improves postprandial glucose and insulin control. Exploratory subgroup analyses showed statistically significant effects for walking and for inter-bout intervals < 60 min, but these comparisons are observational and no formal interaction test was conducted. These findings provide preliminary evidence for acute SBAE in sedentary populations, though long-term health effects and real-world generalisability require further investigation.

Adult↗

PubMed2026

Increasing gut short-chain fatty acids protects intestinal barrier function but does not spare muscle glycogen or impact aerobic performance.

Animal studies suggest gut microbiota-derived short-chain fatty acids (SCFA) provide an intestinal barrier-protecting, glycogen-sparing energy source that increases aerobic endurance performance, but confirmation in humans is needed. This study aimed to determine whether increasing colonic SCFA availability impacts intestinal barrier function, substrate metabolism, muscle glycogen and aerobic performance in healthy adults. Using a randomized, double-blind, crossover design 12 active men (age 18-30 years;40.0 ± 7.1 mL/kg/min) performed prescribed exercise and consumed a provided diet supplemented with acetylated and butyrylated high-amylose maize starch engineered to deliver SCFA to the colon (HAMS-A/B) or low-amylose maize starch (LAMS) for 7 days, separated by a 2 week washout. Indirect calorimetry, stable isotopes and blood, muscle and urine biomarkers were measured on intervention day 8 while participants completed 90 min of steady-state cycle ergometry (ExSS; 60 ± 5%) followed by a 5 km treadmill time trial. HAMS-A/B, relative to LAMS, increased faecal and serum SCFA. Multiple markers of intestinal barrier damage and permeability were lower, and the respiratory exchange ratio during ExSS was higher (0.02 [95% confidence interval (CI): 0.01, 0.03], Ptreatment < 0.001) following HAMS-A/B versus LAMS. However no between-treatment difference in glucose turnover, muscle glycogen depletion (14 µmol/kg/g dry wt. [95% CI: -116, 143], Pinteractio n = 0.613) or TT performance (5 s [95%CI: -44, 54], Ptreatment = 0.816) was observed. Increasing colonic and circulating SCFA modestly altered substrate oxidation and preserved intestinal barrier function during endurance exercise. However effects were not sufficient to spare muscle glycogen or increase aerobic endurance performance, leaving the practical relevance unclear and underscoring challenges inherent in translating promising preclinical findings to humans. KEY POINTS: Animal studies suggest gut microbiota-derived short-chain fatty acids (SCFA) provide an intestinal barrier-protecting, glycogen-sparing energy source that increases aerobic endurance performance, but confirmation in humans is lacking. A gut microbiota-targeted dietary supplementation strategy was used to deliver SCFA to the colon and successfully increased colonic and systemic SCFA concentrations in healthy, physically active adults before and during an endurance exercise bout and aerobic performance test. Increasing colonic and systemic SCFA availability preserved intestinal barrier function but did not impact glucose turnover, alter protein expression in muscle or spare muscle glycogen during endurance exercise. Increasing colonic and systemic SCFA availability did not impact aerobic endurance performance.

Humans↗