Ateş O, Ulupınar S, Kaya K
… +8 more, Tortu E, Türksoy Işım A, Kesler A, İnce İ, Gençoğlu C, Çabuk S, Demirli A, Özbay S
Int J Sport Nutr Exerc Metab
· 2026 Jul · PMID 41791370
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Ramadan-type diurnal fasting, which restricts both food and fluid intake from dawn to sunset, may influence physiological, metabolic, and perceptual responses during high-intensity exercise. However, its acute effects un...Ramadan-type diurnal fasting, which restricts both food and fluid intake from dawn to sunset, may influence physiological, metabolic, and perceptual responses during high-intensity exercise. However, its acute effects under matched external workload conditions in field-based soccer training remain unclear. This study examined the physiological, neuromuscular, metabolic, and perceptual responses to a matched high-intensity intermittent training session performed under fed and Ramadan-type fasting conditions. Twenty male university-level soccer players completed two counterbalanced sessions. External load was matched using 10-Hz GPS monitoring. Physiological variables, including oxygen uptake, carbon dioxide production, respiratory exchange ratio, minute ventilation, and heart rate, along with blood lactate concentration, session rating of perceived exertion, perceptual scales (thermal discomfort and thirst), neuromuscular performance assessed via countermovement jump height and power, and body mass were measured before and after exercise. External mechanical load did not differ between conditions. Ramadan-type fasting elicited significantly higher minute ventilation, mean and maximal heart rate, and session rating of perceived exertion, whereas carbon dioxide production, respiratory exchange ratio, and peak blood lactate concentration were significantly lower. Oxygen uptake did not differ between conditions. Thermal discomfort and thirst increased from pre- to postexercise in both trials (time effect), with perceived thirst showing a greater increase under fasting conditions (interaction effect). Countermovement jump height and power demonstrated significant pre-to-post reductions (time effect) without condition or interaction effects. Body mass decreased significantly from pre- to postexercise in both trials (time effect), with no condition or interaction effects. These findings indicate that Ramadan-type fasting increases internal physiological and perceptual load during high-intensity intermittent soccer training despite identical external workloads, while neuromuscular performance and exercise-induced body mass loss remain preserved. Practitioners should consider that athletes may experience higher internal strain during fasting-based sessions even when mechanical output is maintained.
Suen MW, Tsang JH, Wong PS
… +2 more, O'Reilly J, Poon ET
Int J Sport Nutr Exerc Metab
· 2026 Jul · PMID 41791366
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Carbohydrate (CHO), caffeine (CAF), and menthol (MEN) mouth rinses are emerging ergogenic aids that may enhance sports performance without the gastrointestinal risks of ingestion. However, there is limited evidence speci...Carbohydrate (CHO), caffeine (CAF), and menthol (MEN) mouth rinses are emerging ergogenic aids that may enhance sports performance without the gastrointestinal risks of ingestion. However, there is limited evidence specifically regarding their effects on high-intensity intermittent exercise (HIIE) performance. This systematic review and meta-analysis aimed to evaluate the effect of mouth rinsing on HIIE performance, specifically focusing on solutions containing CHO, CAF, and/or MEN. A comprehensive literature search was conducted using seven databases through June 2025, following the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Twenty randomized crossover studies were included. Overall, our meta-analysis revealed no significant improvement in overall HIIE performance following CHO mouth rinse (standardized mean difference = 0.18; 95% confidence interval [-0.10, 0.46]; p = .21), CAF mouth rinse (standardized mean difference = 0.37; 95% confidence interval [-0.02, 0.75]; p = .06), and CHO + CAF combined mouth rinse (standardized mean difference = -0.19; 95% confidence interval [-0.68, 0.30]; p = .44). Subgroup analysis based on HIIE performance outcomes, including power output, total distance covered, and sprint time, also showed no significant differences for any mouth rinse (p > .05). MEN mouth rinse reported no performance benefits in hot environments, despite an improved cooling sensation. While some individual studies suggested improvements-particularly with low glycogen availability or frequent rinsing-the overall evidence does not support mouth rinsing as an ergogenic strategy for HIIE. Further well-controlled research is needed to define optimal rinse type, timing, frequency, and dietary context for HIIE applications.
Cheng HC, Liu HW, Kuo YC
… +3 more, Yu PH, Yeh KT, Hsieh CH
Int J Sport Nutr Exerc Metab
· 2026 Jul · PMID 41791362
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This study examined how resistance exercise (RE) volume, a potential key factor in appetite regulation, influences subjective appetite, gut appetite hormones, and energy intake. Eighteen males (aged 21-27 years) complete...This study examined how resistance exercise (RE) volume, a potential key factor in appetite regulation, influences subjective appetite, gut appetite hormones, and energy intake. Eighteen males (aged 21-27 years) completed failure RE (FRE; three sets of failure reps at 70% (at 1 RM), non-FRE (NFRE; 3 × 7 reps at 70% 1 RM), and control (CON) trials. Appetite and acyl-ghrelin, peptide YY, lactate, and glucose were measured pre- and postexercise 0-90 min. Ad libitum meal was provided after exercise. Participants recorded energy intake for the day before, the day of, and the day after each session. The incremental area under the curve (iAUC) for acyl-ghrelin (AG) in the FRE and NFRE were significantly lower than in the CON (p < .001). Peptide YY iAUC and glucose iAUC in the FRE were significantly higher than in the CON (p < .001; p = .003). There was a dose-response for lactate iAUC (FRE > NFRE > CON; p < .001). Appetite iAUC was significantly lower in the FRE than in the CON (p = .012). There were no significant differences in postexercise ad libitum meal and self-reported free-living energy intake between the three sessions (p = .246, p = .226). Acyl-ghrelin was negatively correlated with lactate and positively correlated with overall appetite in both RE sessions. Lactate was negatively correlated with overall appetite in both RE sessions. Moderate-intensity RE with moderate volume-induced temporary appetite suppression, whereas FRE led to prolonged suppression and greater appetite-related hormonal responses, yet neither affected energy intake in young males.
Int J Sport Nutr Exerc Metab
· 2026 Feb · PMID 41764997
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Skeletal muscle glycogen depletion is considered one of the key contributing factors toward fatigue and associated performance decrements in soccer. Ensuring adequate carbohydrate availability before and during training...Skeletal muscle glycogen depletion is considered one of the key contributing factors toward fatigue and associated performance decrements in soccer. Ensuring adequate carbohydrate availability before and during training and matches is widely advised as a priority for players, and for that reason, carbohydrate-based fueling guidelines for soccer have been developed. However, the lack of female-specific research used to inform the development of these guidelines raises important questions regarding their applicability for female soccer players. This review critically appraises the likelihood of there being between-sex differences in carbohydrate requirements for soccer performance. Males and females exhibit differences in substrate utilization during exercise, substrate storage capacity, relative quantities of fat and fat-free mass, and running demands of soccer match-play, but the extent to which these differences translate into practically meaningful differences in carbohydrate requirements for soccer performance remains unclear. Based on current evidence, we consider it premature to suggest that female players will require sex-specific guidelines in relation to carbohydrate-based fueling strategies for performance in soccer. However, intervention studies in female players investigating carbohydrate-based fueling strategies before and during soccer match-play or simulated soccer protocols are warranted.
Engel H, Yilmaz C, Appelhans D
… +7 more, Staunton CA, Kock H, Mathieu J, Leitlauf T, Brandl R, Waibel K, Koehler K
Int J Sport Nutr Exerc Metab
· 2026 Mar · PMID 41666907
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Caffeine enhances endurance performance but may impair shooting accuracy, creating a potential trade-off for overall biathlon performance. In a randomized, placebo-controlled, crossover study, seven elite male biathletes...Caffeine enhances endurance performance but may impair shooting accuracy, creating a potential trade-off for overall biathlon performance. In a randomized, placebo-controlled, crossover study, seven elite male biathletes consumed caffeine (3 mg/kg) or taste-matched placebo 60 min before a simulated biathlon competition consisting of five "laps" of 6-min treadmill skiing interspersed by four five-shot bouts. Participants further performed precision shooting (20 prone and 20 standing) pre- and postcompetition. Caffeine increased distance covered in Laps 1 (1,824 ± 73 vs. 1,772 ± 66 m; p = .03, dz = 1.12) and 2 (1,801 ± 92 vs. 1,776 ± 84 m; p = .02, dz = 1.19) but did not improve total distance (p = .06). Blood lactate (p = .01, ηp2=.85) and ventilation (p < .001, ηp2=.90) increased with caffeine. Heart rate (p = .07) and perceived exertion (p = .69) did not differ between conditions. Caffeine impaired shooting accuracy in standing (72.9 ± 16.0% vs. 82.9 ± 7.6%; p = .03, dz = 0.87), but not prone. Integrated race times did not differ between conditions for individual (71.72 ± 5.27 vs. 71.58 ± 4.57 min), mass start (52.45 ± 3.67 vs. 52.57 ± 3.27 min), or pursuit (44.18 ± 3.18 vs. 44.23 ± 2.83 min; all p > .77) formats. Caffeine impaired postexercise precision shooting in prone position (88.9 ± 6.0% vs. 93.3 ± 7.5%; p = .04, dz = 0.65). Our findings highlight task-specific effects of caffeine, emphasizing the importance of tailoring supplementation to integrated performance demands.
McCubbin AJ, Leng SD, Young KJ
… +2 more, Demeo JL, Costa RJS
Int J Sport Nutr Exerc Metab
· 2026 Mar · PMID 41570812
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High-amylose maize starch (HAMS), containing fermentable resistant starch (RS), is suggested to improve fluid absorption/retention in athletes but lacks supporting evidence and may increase gastrointestinal symptom (GIS)...High-amylose maize starch (HAMS), containing fermentable resistant starch (RS), is suggested to improve fluid absorption/retention in athletes but lacks supporting evidence and may increase gastrointestinal symptom (GIS) risk. This study investigated the use of HAMS in pre- and postexercise hydration protocols on hydration status and GIS before, during, and after exertional heat stress (EHS), and thermophysiological strain and exhaustive exercise performance during EHS. Ten endurance-trained runners (eight men and two women) completed two trials in randomized order, consuming a HAMS beverage (12.7 g RS) or placebo 12 hr pre-EHS as part of a 25-ml/kg hyperhydration protocol. Participants then completed 2 hr of steady-state running (60% maximum oxygen uptake, ∼30 °C, 35% relative humidity) followed by a time-to-exhaustion performance test. Post-EHS, participants consumed a HAMS recovery beverage (6.2 g RS) or placebo while replacing 150% of their fluid deficit over 3 hr. HAMS did not influence net fluid balance pre-EHS (HAMS: +44 ± 642 ml, placebo: +210 ± 697 ml) or post-EHS (HAMS: +1,636 ± 687 ml, placebo: +1,662 ± 697 ml; p = .40). Changes in plasma volume and osmolality, and thermophysiological variables, did not differ between trials (all p > .05). Time-to-exhaustion performance test was unaffected by the intervention (HAMS: 1,190 ± 508 s, placebo: 1,343 ± 631 s; p = .10). GIS incidence and severity scores were similar in both trials (all p > .05). A beverage containing RS from HAMS 12 hr before EHS, or immediately following EHS, does not alter retention of water volumes recommended for preexercise hyperhydration or postexercise rehydration nor GIS pre-, during, or post-EHS. As a result, no changes in hydration status, thermophysiological strain, or performance were observed.
Int J Sport Nutr Exerc Metab
· 2026 May · PMID 41570809
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The use of sports foods and supplements has become ubiquitous among cyclists of all disciplines in order to meet energy and nutrient targets and to improve performance and recovery outcomes. This review will provide an o...The use of sports foods and supplements has become ubiquitous among cyclists of all disciplines in order to meet energy and nutrient targets and to improve performance and recovery outcomes. This review will provide an overview of the different types of products and the rationale for their use, while highlighting key considerations surrounding the safety and anti-doping risks that supplements pose among athletes. A summary of supplements with a strong evidence base (caffeine, creatine, sodium bicarbonate, beta-alanine, dietary nitrate, and glycerol) and emerging supplements popularized within cycling (exogenous ketones) is also provided, outlining accepted protocols for use, timing, and potential ergogenic effects or side effects.
Han TS, Keen KT, Selvanayagam VS
… +1 more, Yusof A
Int J Sport Nutr Exerc Metab
· 2026 Mar · PMID 41569832
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Mouth rinsing with carbohydrates or salt solutions has been shown to attenuate the reduction in maximum voluntary contraction (MVC) strength during fatigue. Although central mechanisms, such as changes in voluntary activ...Mouth rinsing with carbohydrates or salt solutions has been shown to attenuate the reduction in maximum voluntary contraction (MVC) strength during fatigue. Although central mechanisms, such as changes in voluntary activation (VA) and motor evoked potentials (MEP), have been proposed to explain this effect, direct evidence is limited. This study aimed to investigate the effects of carbohydrate or salt mouth rinses on central fatigue by examining whether central measures are affected. In a double-blind, randomized, crossover design, 19 male participants completed three experimental trials (carbohydrate, salt, or placebo mouth rinses), each involving a sustained knee isometric fatiguing protocol performed until volitional fatigue. MVC, VA, and MEP were assessed before and after the fatiguing protocol. Following the protocol, the torque output (MVC) and central measures (VA and MEP) showed significant reductions (p < .05). Although the reductions following carbohydrate and salt were less pronounced (MVC, VA, and MEP), both treatments showed better preservation than placebo (p < .001). In addition, the comparable reduction in resting twitch and maintenance of maximum compound muscle action potential (p > .05) suggest that the observed benefits were primarily central mediated. This is the first study to demonstrate that salt mouth rinsing is as effective as carbohydrate rinsing in attenuating neuromuscular fatigue via central mechanisms, preserving muscle activity, central drive, and corticospinal responsiveness following a localized fatiguing protocol.
Int J Sport Nutr Exerc Metab
· 2026 May · PMID 41569815
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Novel cycling disciplines, such as cycling Esports and gravel racing, have recently seen a surge in participation, media visibility, and the establishment of international competitions. However, there is limited peer-rev...Novel cycling disciplines, such as cycling Esports and gravel racing, have recently seen a surge in participation, media visibility, and the establishment of international competitions. However, there is limited peer-reviewed research into the specific physiological and nutritional demands required for success in these disciplines. As part of the larger UCI Sports Nutrition project, this review utilizes qualitative interviews to gain a deeper understanding of the nutrition practices of athletes currently competing in these events. We contextualize these responses by describing contemporary nutrition strategies and evidence-based practice adopted from other disciplines, along with practical application considering the distinct challenges presented by these new and emerging cycling disciplines. Key issues for these disciplines include in race nutrition targeting the specific needs of the event, noting that the logistics of consuming food and drinks in gravel racing and Esports are different to other modalities such as road cycling. Optimization of body mass is a shared concern particularly in Esports in which the requirement for a prerace "weigh-in" may lead to practices usually seen in weight division sports. Finally, a number of supplements including caffeine, creatine, buffering agents, and hyperhydrating agents such as glycerol may enhance performance when used according to evidence-based protocols.
Ferri-Marini C, Garcia Murillo OG, Corral-Castillo DA
… +3 more, Amaro-Gahete FJ, Peric R, Chavez Guevara IA
Int J Sport Nutr Exerc Metab
· 2026 Mar · PMID 41569814
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OBJECTIVE: To synthesize current evidence on sexual dimorphism in maximal fat oxidation (MFO) and its corresponding exercise intensity (FATmax), exploring key moderators influencing these parameters across populations. M...OBJECTIVE: To synthesize current evidence on sexual dimorphism in maximal fat oxidation (MFO) and its corresponding exercise intensity (FATmax), exploring key moderators influencing these parameters across populations. METHODS: We conducted a systematic review and meta-analysis, registered in PROSPERO (CRD42024563620), following Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. PubMed, Scopus, and EBSCOhost databases were searched from January 2001 to April 2024 for English- and Spanish-language studies examining MFO and FATmax during graded exercise tests. Studies were included if they reported sex-specific MFO and/or FATmax values derived from indirect calorimetry. Both cross-sectional and longitudinal designs were considered. Exclusion criteria included pooled-sex data, inaccessible full texts, and nonexercise-based MFO assessments. RESULTS: Thirty-six studies (n = 8,990; 5,133 females, 3,857 males) were included. Absolute MFO was significantly lower in females (MD: -0.06 g/min), but no significant differences were observed in relative MFO (standardized mean difference: 0.202, p = .096) or FATmax (mean difference: 1.29% VO2max, p = .254). Cardiorespiratory fitness, body mass index, and exercise modality were key moderators in both sexes. Treadmill exercise was associated with higher MFO, irrespective of sex. Notably, body mass index and age influenced sexual dimorphism in fat oxidation, with age showing a curvilinear (quadratic) relationship with FATmax, suggesting complex age-related adaptations (p = .008). CONCLUSIONS: This review questions the assumption that women consistently oxidize more fat than men during exercise. The influence of sex on fat metabolism appears context-dependent, emphasizing the need for individualized interpretation. Longitudinal studies are required to evaluate whether these differences confer cardiometabolic protection.
Bell M, Narciso PH, MacNeil AJ
… +4 more, Josse AR, Roy BD, Falk B, Klentrou P
Int J Sport Nutr Exerc Metab
· 2026 Mar · PMID 41493773
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The effects of Greek yogurt and whey protein supplementation on markers of bone turnover and inflammation were compared in university athletes over a competitive season. Participants (n = 32, 16 females) followed their h...The effects of Greek yogurt and whey protein supplementation on markers of bone turnover and inflammation were compared in university athletes over a competitive season. Participants (n = 32, 16 females) followed their habitual diets for an 8-week control period and were then randomly assigned to one of two trial arms: two servings per day of either 175 g of Greek yogurt (17 g protein) or isonitrogenous whey protein for a 16-week intervention period. Morning, fasting blood was collected at Weeks 0 (precontrol), 8 (postcontrol/preintervention), 16 (midintervention), and 24 (postintervention) and analyzed for osteocalcin, amino-terminal propeptide of Type I collagen, insulin-like growth factor 1, osteoprotegerin, C-telopeptides of Type I collagen, sclerostin, receptor activator of nuclear factor kappa-B ligand, tumor necrosis factor-alpha, interleukin 6, and interleukin 10. No main effects or interactions were found for markers of bone formation. In the Greek yogurt group, C-telopeptides of Type I collagen increased from pre- to postcontrol and returned to baseline concentrations postintervention while remaining stable throughout the study in whey protein (Time × Group interaction, p = .048). Receptor activator of nuclear factor kappa-B ligand increased from pre- to postcontrol (time effect, p = .014), returning to baseline by midintervention across groups. Males had higher sclerostin (sex effect, p = .021) and interleukin 10 (sex effect, p = .004) with no interactions. Interleukin 6 showed no main effects or interactions. Tumor necrosis factor-alpha increased pre- to postcontrol (time effect, p = .053) then decreased to baseline levels postintervention. Although protein supplementation, independent of source (wholefood or isolates), showed potential bone and inflammatory benefits during athletic training, it remains unclear whether these effects were solely attributable to the supplements.
Wardenaar FC, Burns SF, Campos M
… +17 more, Chan Y, Claassen-Smithers A, Dunshea-Mooij C, Haddou SE, Hoogervorst D, Jagim A, Garcia PR, Garthe I, Nugent AP, Aly MO, Saunders B, Schott KD, Sekiguchi Y, Slater G, Speers N, Stratton MT, Aussieker T
Int J Sport Nutr Exerc Metab
· 2026 Mar · PMID 41468235
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Nutritional supplement use is common among athletes aiming to enhance performance, recovery, and health. However, variable regulatory frameworks and limited safety oversight create risks for inadvertent doping violations...Nutritional supplement use is common among athletes aiming to enhance performance, recovery, and health. However, variable regulatory frameworks and limited safety oversight create risks for inadvertent doping violations. This article provides a global overview of supplement use, relevant authorities, legislation, and safety measures, with a focus on third-party testing (TPT) as a risk-mitigation strategy. Data from six global regions-Africa, Asia, Australia/New Zealand, Europe, Latin America, and North America-were synthesized from peer-reviewed studies, governmental sources, and regional expert contributions. Reported supplement use ranged from 7% to 100% among athletes (variability within regions), with protein powders, vitamins/minerals, creatine, caffeine, and sports drinks being most prevalent. High-risk products (potential anti-doping rule violations), including certain herbal blends, preworkouts, and weight-management supplements, were reported across all regions. While some countries have robust regulatory systems, most lack harmonized or enforceable safety frameworks. TPT programs, which independently verify products for prohibited substances, remain concentrated in the global northwest (Europe, North America, and Australia/New Zealand); awareness and use of TPT certification vary widely, and even in regions with established systems, athlete adherence is inconsistent. Barriers to low-risk supplement use are limited TPT availability, cost, differences in labeling (including language), and cultural factors. Firsthand experiences and perceptions highlight widespread misconceptions about supplement safety and certification. The authors recommend expanded athlete and team-around-the-athlete education, improved global access to TPT low-risk supplements, and policy initiatives to harmonize safety standards. This work emphasizes the need for coordinated international efforts to protect athlete health and integrity while allowing access to evidence-based supplementation.
Saffioti N, Takarabe LL, Perfeito LAM
… +4 more, Ribeiro WJD, Hilkens L, van Dijk JW, Dolan E
Int J Sport Nutr Exerc Metab
· 2026 May · PMID 41468224
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As a group, cyclists tend to have lower bone mass compared with other athletes, and nonathlete controls which may have negative consequences for fracture risk and longer term bone health. There are several cycling-specif...As a group, cyclists tend to have lower bone mass compared with other athletes, and nonathlete controls which may have negative consequences for fracture risk and longer term bone health. There are several cycling-specific factors that may contribute to this finding. These include, the low-impact, repetitive load nature of cycling which provides limited stimulus for bone metabolism; metabolic perturbations that occur following prolonged cycling that may lead to a transient increase in the rate of bone resorption; and nutritional factors, including low energy availability or nutrient inadequacy. Furthermore, many endurance cyclists are naturally lean and light, which may result from both genetic predisposition and long-term training adaptations. In turn, they may also have lower bone mass. None of these factors stand out as the primary cause of the low bone mass reported in cyclists but, instead, may combine to create a "perfect storm" to challenge cyclist bone health. Given these multiple potential challenges to bone health, a multifaceted approach may be required to combat them. On an individual level, nutritional strategies, including ensuring adequate energy, carbohydrate, protein, calcium, vitamin D, and other important micronutrients may be key to protecting cyclist bone health. Integrating brief bouts of high-impact loading within the training regimen and ensuring adequate sleep and recovery are also recommended. The onus should not remain solely on the individual, however, and cycling teams and organizational bodies have a key role to play in providing screening and educational strategies to support cyclists bone health.
Cheung S, Stellingwerff T, Stanley J
… +3 more, Mujika I, Nybo L, Girard O
Int J Sport Nutr Exerc Metab
· 2026 May · PMID 41468209
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Elite cyclists frequently train and compete in extreme environments, such as heat, and cold conditions that are becoming more common due to climate change. Altitude training, aimed at preparing athletes for high-altitude...Elite cyclists frequently train and compete in extreme environments, such as heat, and cold conditions that are becoming more common due to climate change. Altitude training, aimed at preparing athletes for high-altitude events, is widely employed to enhance subsequent sea-level performance. Similarly, heat training has proven to have a similar transfer effect, in addition to the essential acclimatization effects, relevant for performance in hot conditions. Exposure to these challenging environments increases physiological stress raising energy and carbohydrate oxidation rates, and affecting overall performance. This Union Cycliste Internationale (UCI) consensus on nutrition for cycling addresses the nutritional challenges associated with extreme environmental conditions and explores tailored nutrition and hydration strategies to mitigate their effects. The review examines how heat, cold, and altitude affect hydration, energy expenditure, and metabolism, with associated macro- and micronutrient considerations, in cyclists. It discusses practical strategies for managing fluid balance, carbohydrate intake, and micronutrient and electrolyte supplementation and the use of ergogenic aids in supporting adaptation to environmental stresses. This review provides evidence-based nutrition and fluid recommendations for optimizing cycling performance and fostering adaptation in extreme environments. It offers practical guidance on nutrition and hydration strategies before, during, and after training and competition, helping cyclists maintain peak performance while navigating the unique challenges posed by these conditions.
Int J Sport Nutr Exerc Metab
· 2026 Mar · PMID 41468185
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OBJECTIVE: This study examined the effects of different carbohydrate ingestion patterns on endurance cycling performance and gastrointestinal comfort. It was hypothesized that increasing carbohydrate availability in alig...OBJECTIVE: This study examined the effects of different carbohydrate ingestion patterns on endurance cycling performance and gastrointestinal comfort. It was hypothesized that increasing carbohydrate availability in alignment with decreasing endogenous stores would optimize performance while minimizing gastrointestinal discomfort. METHODS: Twelve trained male cyclists completed three randomized trials involving a 180-min intermittent cycling preload, a 15-min all-out performance test, and a maximal sprint to exhaustion. Participants ingested 90 g/hr of carbohydrates in an increasing (INC), decreasing (DEC), or constant (CON) pattern. Performance, substrate oxidation, rate of perceived exertion, and gastrointestinal comfort were assessed. RESULTS: Carbohydrate distribution during exercise had no effect on 15-min all-out performance test (mean [95% confidence limits]: INC-CON -0.1% [-9.9, 11]; INC-DEC 5.9% [-8.6, 23]; DEC-CON -5.4 [-17, 7.8]) or time to exhaustion (INC-CON -0.6 [-3.8, 2.7]; INC-DEC 0.1 [-4.0, 4.4]; DEC-CON -0.7 [-4.0, 2.6]) performance. Carbohydrate oxidation was higher in DEC versus CON (7.1%; 2.7, 11.7) and versus INC (5.8%; -4.1, 15). Conversely, fat oxidation was lower in DEC versus CON (13%; -23, -1.8), while other contrasts were unclear. RPE was lower, but increased more over time in INC than CON. Nausea (standardized difference 1.2; 0.04, 2.3), stomach fullness (0.55; -0.15, 1.27), and abdominal cramping (0.84; -0.03, 1.7) increased over time in INC versus DEC. CONCLUSION: Carbohydrate intake distribution had little clear effect on performance, though a decreasing pattern may support oxidation and gut comfort later in exercise. Even intake remains advisable, but uneven patterns may be acceptable when needed.