The research team, led by Erfan Berjisian of Edith Cowan University and colleagues from institutions in Australia, the United Arab Emirates and beyond, followed Joanna Briggs Institute guidelines and searched eight databases, including Web of Science, Scopus, SPORTDiscus, CINAHL, the Cochrane Library, Embase, MEDLINE and PubMed. Methodological quality was appraised with the AMSTAR 2 checklist, and the certainty of evidence was graded using the GRADE framework. The review was prospectively registered with PROSPERO, and the authors calculated the degree of overlap between the included reviews using the corrected covered area formula, which came out at 10.4 percent, indicating moderate overlap overall, although the reviews examining strength and hypertrophy adaptations shared a striking 64 percent of their primary studies.

The headline finding is that cold-water immersion is neither a universal elixir nor a useless fad; its effects are sharply dependent on the outcome being measured and the timing of the next performance demand. For muscular strength recovery, the evidence was consistently underwhelming. Across four meta-analyses, immersion produced no significant improvement in maximal strength compared with passive rest or alternative recovery modalities at any timepoint up to 168 hours after exercise, with standardised mean differences hovering near zero. Athletes hoping that a cold plunge will restore their deadlift or squat strength faster appear to be hoping in vain.

By contrast, explosive and power-based performance told a far more interesting, time-dependent story. Jump performance was actually impaired in the first hours after immersion, with one meta-analysis reporting a large and significant drop in jump height of 2.71 centimetres when tested immediately after cooling, a finding consistent with well-established physics: colder muscle contracts more slowly and produces less power. But the picture reversed dramatically with time. The same review found a large improvement of 4.77 centimetres at 24 hours, and other analyses confirmed small-to-large gains in jump performance between 24 and 96 hours. Muscular power followed a similar pattern, improving significantly at 24 to 72 hours after both eccentric and high-intensity exercise, with pooled effect sizes reaching 0.65 in some analyses.

Endurance performance showed yet another temporal signature. A meta-analysis of fourteen studies found a significant improvement in endurance performance when testing occurred within roughly one hour of immersion, with a standardised mean difference of 0.50, but the benefit vanished at six, 24 and 48 hours. This pattern makes physiological sense: cold-water immersion rapidly lowers tissue temperature and cardiovascular strain, which is precisely what a fatigued athlete needs before a second bout in hot conditions or during tournament play with matches on consecutive days. Beyond that acute window, however, the review found no support for cold-water immersion as a strategy to blunt cumulative endurance fatigue across multiple days of training or competition.

Perhaps the most consequential finding concerns chronic adaptation. When cold-water immersion was applied repeatedly after resistance training over several weeks, it attenuated gains in one-repetition maximum, maximal isometric strength, strength endurance and ballistic performance, with effect sizes ranging from negative 0.50 to negative 0.73 in one meta-analysis. A Bayesian meta-analysis concluded that regular post-exercise immersion likely reduces resistance training-induced hypertrophy, albeit modestly, with a corrected standardised mean difference of negative 0.22. Intriguingly, the mode of immersion mattered: subgroup analyses showed that immersing only the exercised limbs significantly blunted strength gains, whereas whole-body immersion showed no meaningful detrimental effect compared with control. Endurance adaptations, meanwhile, appeared largely unaffected, with trivial pooled effects on time-trial performance and maximal aerobic power.

The mechanistic explanation for these blunted gains lies in molecular biology rather than in the tub itself. Experimental work has shown that cold-water immersion after resistance exercise dampens anabolic signalling, reduces ribosome biogenesis and satellite cell activity, and directly impairs muscle protein synthesis rates. Cooling, in effect, suppresses the very inflammatory and signalling processes that drive muscle to grow stronger and larger after heavy training. For athletes in a strength- or hypertrophy-focused training block, the practical implication is stark: the ice bath should be kept well away from the key lifting sessions, even if it is deployed strategically after technical or aerobic work elsewhere in the week.

Not every effect was negative or neutral. Cold-water immersion consistently reduced muscle soreness from one hour up to 96 hours after exercise, with small-to-moderate effects that were largest following high-intensity exercise. It also lowered circulating creatine kinase, a marker of muscle damage, significantly between 24 and 72 hours post-exercise, with pooled effects reaching negative 1.30, although no effect was seen in the first six hours or at 96 hours. Inflammatory markers told a different story: C-reactive protein and interleukin-6 were essentially unchanged up to 72 hours, suggesting that the soreness and damage-marker benefits do not require broad suppression of systemic inflammation. On the autonomic front, a single meta-analysis of fifteen studies reported a moderate-to-large improvement in vagally mediated heart rate variability, indicating faster parasympathetic reactivation, with colder water around 9 to 15 degrees Celsius outperforming thermoneutral immersion at 28 to 35 degrees.

The review also offered practical dosing guidance. Immersions of 10 to 15 minutes at water temperatures of 10 to 15 degrees Celsius appeared most effective for reducing muscle soreness, while 10 to 15 minutes at 5 to 10 degrees Celsius had the highest probability of being optimal for lowering creatine kinase and improving jump performance at 24 to 48 hours. Intermittent and continuous protocols performed similarly, and longer immersions of 16 to 20 minutes were not consistently beneficial, with experimental work cautioning that prolonged or aggressive cooling may impair glycogen restoration and delay recovery from muscle damage.

The authors are candid about the limitations of the evidence base. All fifteen included reviews were rated as low or critically low methodological quality, and most outcomes carried low to very low certainty of evidence, driven mainly by inconsistency, imprecision and the near-impossibility of blinding participants to frigid water. Roughly 90 percent of participants were male, leaving sex-specific responses to cold exposure largely unexplored. Still, the overarching message is clear and actionable: cold-water immersion should be periodised and individualised rather than applied routinely after every session. It is most defensible when recovery time is short, thermal strain is high, and the next bout is imminent, and it should be avoided immediately before explosive performance and during phases where strength and muscle growth are the priority. The ice bath, it turns out, is a precision tool, not a daily ritual.

Subject of Research: Effects of post-exercise cold-water immersion on athletic performance recovery and training adaptation

Article Title: Strategic Application of Post-exercise Cold-Water Immersion to Enhance Performance Recovery and Adaptation: An Umbrella Review of 15 Published Systematic Reviews with Meta-analysis

Article References: Berjisian, E., Miraftabi, H., Ihsan, M., Homer, K. A., Kendall, K., Roberts, L., & Abbiss, C. (2026). Strategic Application of Post-exercise Cold-Water Immersion to Enhance Performance Recovery and Adaptation: An Umbrella Review of 15 Published Systematic Reviews with Meta-analysis. Sports Medicine – Open, 12(1), Article 145. https://doi.org/10.1186/s40798-026-01116-8

Image Credits: AI Generated

DOI: 10.1186/s40798-026-01116-8

Keywords: cold-water immersion, exercise recovery, athletic performance, muscle soreness, creatine kinase, strength training, hypertrophy, endurance performance, heart rate variability, meta-analysis, sports medicine, recovery protocols

The logic behind CoQ10 supplementation is seductively straightforward. The molecule is an essential cofactor in the mitochondrial electron transport chain, shuttling electrons between complexes I and III during oxidative phosphorylation, the process that generates the bulk of cellular ATP. It also functions as a powerful lipid-phase antioxidant, quenching the free radicals that attack cell membranes. Because strenuous exercise dramatically increases oxygen flux through working muscles, it simultaneously increases the production of reactive oxygen species. Exercise-induced oxidative stress has been proposed as a mechanistic link between heavy training loads, membrane injury, impaired recovery, and inconsistent performance responses. Supplementing with the antioxidant cofactor that sits at the crossroads of energy production and radical defense therefore seemed like an obvious win for athletes, even as individual randomized trials kept returning contradictory results.

To resolve that contradiction, the Chinese research team conducted a prospectively registered systematic review, searching PubMed, Web of Science, Embase, and EBSCOhost from database inception to April 2026, with the protocol registered in PROSPERO under identifier CRD420261370320. They included randomized parallel-group and crossover trials evaluating oral CoQ10 in athletes or athlete-relevant trained individuals. The final tally was twenty-four studies encompassing 613 participants for the systematic review, with fifteen studies and 330 participants contributing to at least one quantitative synthesis. Because several studies contributed more than one eligible estimate, the unit of quantitative reporting was the effect size or comparison, and random-effects models were used throughout the meta-analysis.

The headline result concerns malondialdehyde, or MDA, a widely used biomarker of lipid peroxidation that serves as a chemical fingerprint of oxidative damage to cell membranes. The primary pooled analysis for MDA included seven effect sizes drawn from five studies and was not statistically significant, with a standardized mean difference of negative 0.96 and a 95 percent confidence interval spanning from negative 2.07 to positive 0.15. In other words, the point estimate suggested a substantial reduction in oxidative damage, but the uncertainty was so wide that the result could not be distinguished from chance. A sensitivity analysis tightened the interval to negative 0.93 with a confidence interval of negative 1.65 to negative 0.22, favoring CoQ10, yet the authors emphasize that this signal remained fragile, burdened by residual heterogeneity with an I-squared statistic of 73 percent, small sample sizes, and methodological limitations in the underlying trials.

The physiological picture was even more definitive. The representative pooled performance outcome, maximal oxygen uptake or VO2max, included eight effect sizes from seven studies and was essentially neutral, with a standardized mean difference of 0.03 and a confidence interval of negative 0.32 to positive 0.39. The I-squared statistic of 0.0 percent indicates remarkable consistency across trials, but the consistency points to a null effect rather than a benefit. Supplementary pooled analyses were likewise neutral for blood pressure, creatine kinase, interleukin-6, total antioxidant capacity, tumor necrosis factor-alpha, and anaerobic threshold. For a supplement whose promotional materials promise everything from faster recovery to enhanced endurance capacity, the absence of any measurable effect on inflammation, muscle damage, cardiovascular parameters, or aerobic fitness represents a comprehensive null result.

Perhaps the most damning statistic in the entire analysis concerns the quality of the evidence itself. Using the revised Cochrane risk-of-bias tool, the authors judged overall risk of bias as raising some concerns in twenty-three of the twenty-four included studies, or 95.8 percent, with one study judged at high risk, or 4.2 percent. Not a single trial emerged unscathed. This matters because biased trials tend to inflate effect estimates, which means the modest signals that did emerge may themselves be overestimates. The finding echoes a persistent problem in sports nutrition research, where small samples, short durations, and commercial entanglements frequently undermine the reliability of individual studies, leaving meta-analysts to extract signal from noise.

There is, however, a nuanced thread running through the narrative synthesis. The authors observed more coherent, context-dependent signals in studies conducted under conditions of marked oxidative or recovery stress, such as elite swimmers combining supplementation with pre-cooling strategies, or athletes undergoing intensive training camps. This pattern fits with a broader understanding of exercise physiology: reactive oxygen species are not simply damaging byproducts but also serve as signaling molecules that trigger adaptive responses, including endogenous antioxidant enzyme upregulation and mitochondrial biogenesis. Blunting oxidative stress indiscriminately during moderate training might even interfere with adaptation, whereas athletes under extreme oxidative loads could plausibly benefit from additional antioxidant capacity. The review cannot confirm this hypothesis, but it offers a framework for designing better-targeted future trials.

The biochemistry of CoQ10 also helps explain why results have been so inconsistent. The molecule is highly lipophilic and poorly absorbed, and plasma response to oral ingestion varies substantially between formulations, with ubiquinol, the reduced form, generally achieving higher circulating concentrations than ubiquinone. Studies have shown that supplementation does reliably enrich plasma and blood cells, yet raising blood levels does not guarantee that the coenzyme reaches the mitochondria of working muscle in sufficient quantities to alter electron transport flux or membrane protection. A recent companion study cited in the review found that CoQ10 supplementation raised plasma levels without improving mitochondrial function in older adults, underscoring the gap between what blood tests measure and what muscle cells actually experience.

For the global supplement market, where CoQ10 products are frequently marketed to endurance athletes and fitness enthusiasts, the implications are uncomfortable. The new analysis aligns with earlier systematic reviews, including a 2024 GRADE-assessed dose-response meta-analysis and a 2025 review in the British Journal of Nutrition that found limited and inconsistent effects on exercise performance despite reliable increases in blood concentrations. The consistent pattern across independent teams, databases, and decades of trials, stretching back to studies of trained cyclists and cross-country skiers in the 1990s, suggests that the null findings are not an artifact of any single analysis but a genuine property of the intervention in healthy, well-trained populations.

The authors stop short of declaring CoQ10 useless, and their caution is warranted. The potentially favorable MDA signal in the sensitivity analysis, the hints of benefit under extreme oxidative stress, and the heterogeneity of study designs all leave room for refined hypotheses, perhaps involving specific populations, dosing regimens, or combinations with other interventions. But for the average athlete contemplating a daily capsule in pursuit of a competitive edge, the message from this comprehensive synthesis is clear: the best available evidence shows no meaningful improvement in aerobic capacity, muscle damage markers, inflammation, blood pressure, or antioxidant status. Until higher-quality trials demonstrate otherwise, the molecule that powers mitochondria appears unable to power personal bests.

Subject of Research: Effects of coenzyme Q10 supplementation on exercise-induced oxidative stress and physiological outcomes in athletes

Article Title: The effects of coenzyme Q10 supplementation on exercise-induced oxidative stress and related physiological outcomes in athletes: a systematic review and meta-analysis

Article References: Lu, S., Zhong, W., & Wang, H. (2026). The effects of coenzyme Q10 supplementation on exercise-induced oxidative stress and related physiological outcomes in athletes: a systematic review and meta-analysis. 3 Biotech, 16(10), Article 445. https://doi.org/10.1007/s13205-026-05076-4

Image Credits: AI Generated

DOI: 10.1007/s13205-026-05076-4

Keywords: coenzyme Q10, athletes, oxidative stress, malondialdehyde, VO2max, meta-analysis, systematic review, sports nutrition, mitochondria, exercise physiology, dietary supplements, recovery