The running science nerd alert.
Learn to train smart, run fast, and be strong with Thomas Solomon PhD 
April 2024
The latest research studies on exercise science and sports nutrition are here.
You can use them to help level up your running performance or coaching practice.
The studies are divided into sub-topics:
training methods, sports nutrition and hydration, sports supplements, recovery (inc. sleep), athlete health (inc. mental health), injuries and rehab, and female athlete physiology. Plus, there’s my beer of the month to wash it all down.
I’ve provided a brief conclusion from each study but click on the study title to go deep and read the full paper.
My favourite paper this month.
A systematic review and meta-analysis that me and my good friend and collaborator Matt Laye have been working on for 2 years: The effect of post-exercise heat exposure (passive heat acclimation) on endurance exercise performance: A systematic review and meta-analysis. Thomas Solomon and Matthew Laye (2024) SportRxiv (a preprint); paper currently under peer review.
“The current evidence shows that heat acclimation using post-exercise heat exposure might improve physiological responses during submaximal exercise (causing increased sweat rate and decreased heart rate, core temperature, and thermal sensations). However, given the predominance of low to very low certainty evidence, the effect of this method of heat acclimation on endurance exercise performance is uncertain. Further high-quality trials are needed to bolster the evidence and to enable conclusions concerning the efficacy of post-exercise heat exposure for improving endurance exercise performance.”
Training methods.
Randomised controlled trial: Independent, additive and interactive effects of acute normobaric hypoxia and cold on submaximal and maximal endurance exercise. Callovini et al. (2024) Eur J Appl Physiol. “ The combination of cold (−20°C) and hypoxia (≈3500 m) exerted additive rather than synergistic effects on exercise performance, decreasing lactate threshold and maximal exercising workload to an extent that is equal to the sum of the two stimuli alone. Both exclusive effects of hypoxia (i.e., maximal and submaximal pulse oxygen saturation, submaximal respiratory frequency, and RPE at lactate threshold) and cold (i.e., submaximal tidal volume and thermal sensation) and different additive (i.e., maximal heart rate and heart rate at lactate threshold, maximal minute ventilation) and synergistic (i.e., maximal thermal sensation and minute ventilation at lactate threshold) effects of the two stressors were found on the investigated maximal and submaximal physiological and perceptual variables. Future studies should (i) better understand the magnitude of influence of cold-induced bronchoconstriction on exercise performance, especially when combined to acute hypoxic ventilatory response and (ii) consider combined cold and hypoxic effect on performance when also a significant reduction in core and muscle temperature is expected, accurately measuring these parameters. These results provide new insight into human responses to exercise in cold and hypoxic environments, highlighting the need for careful consideration of independent and combined stressor impact on considered variables for optimal exercise intensity prescription and training load monitoring in athletes training/competing in hypoxic and/or cold environments.” A systematic review and meta-analysis that me and my good friend and collaborator Matt Laye have been working on for 2 years: The effect of post-exercise heat exposure (passive heat acclimation) on endurance exercise performance: A systematic review and meta-analysis. Thomas Solomon and Matthew Laye (2024) SportRxiv (a preprint); paper currently under peer review. “The current evidence shows that heat acclimation using post-exercise heat exposure might improve physiological responses during submaximal exercise (increased sweat rate and decreased heart rate, core temperature, and thermal sensations). However, given the predominance of low to very low certainty evidence, the effect of this method of heat acclimation on endurance exercise performance is uncertain. Further high-quality trials are needed to bolster the evidence and to enable conclusions concerning the efficacy of post-exercise heat exposure for improving endurance exercise performance.”Sports supplements.
Randomised controlled trial: A Ketone Monoester with Carbohydrate Improves Cognitive Measures Postexercise, but Not Performance in Trained Females. Waldman et al. (2024) Med Sci Sports Exerc. “ In conclusion, the ingestion of a ketone monoester (KE4, KetoneAid: (R)-1,3-hydroxybutyl R-3-hydroxybutrate) + carbohydrate (Gatorade) beverage induced no ergogenic or ergolytic effects on markers of the 10-km time trial performance in comparison with carbohydrate alone within a trained female cohort. However, the ingestion of the ketone monoester + carbohydrate beverage did induce favourable effects on various tests of cognitive performance immediately after the time trial (and that being after ≈60 min of total exercise time). Together with similar findings from male participants in previous work, these data suggest a possible role for the (R)-1,3-hydroxybutyl R-3-hydroxybutrate ketone monoester for benefits on cognitive performance in an athletic context. Other work identifying possible roles for exogenous ketone supplements in recovery, traumatic brain injury, acute hypoxia, or anabolic signalling is required to be done with a greater emphasis on the female athlete.” Systematic review and meta-analysis: Does acute cannabidiol (CBD) use impair performance? A meta-analysis and comparison with placebo and delta-9-tetrahydrocannabinol (THC). Lo et al. (2024) Neuropsychopharmacology. “This meta-analysis suggests acute cannabidiol (CBD) consumption may be associated with a small increase in subjective sedation compared to placebo in infrequent cannabis users, but does not significantly impact performance across a range of cognitive domains. These results are consistent with previous evidence supporting that CBD consumption does not impact neurocognitive function. As such, acute use of CBD in the absence of tetrahydrocannabinol (THC) or other drugs is unlikely to lead to functional impairment. Further research is warranted to investigate the risk of impaired neurocognitive function with daily CBD consumption, in addition to assessing performance in alternative domains.” Systematic review and meta-analysis: The effect of curcumin supplementation on functional strength outcomes and markers of exercise-induced muscle damage: A systematic review and meta-analysis. Oxley and Peart (2024) Nutr Health. “ The aim of this systematic review and meta-analysis was to investigate the potential use of curcumin ingestion to improve functional strength, exercise-induced muscle damage, delayed-onset muscle soreness, and/or inflammation. In this regard, while individual research may have observed a beneficial effect, this research found no evidence of statistically significant changes upon analysis. Furthermore, this study highlights the need for methodological standardisation, as varying research methods may describe across-study heterogeneity, rather than the variable potential impact of curcumin supplementation. Lastly, this study highlights the need for more research into markers of functional strength. As the evidence base for functional strength may be limited, research investigating this outcome may be disproportionately open to bias. Consequently, to thoroughly examine if an effect exists, substantially more research is needed for all outcome variables.”Recovery (including sleep).
Observational study: The effects of sleep deprivation and extreme exertion on cognitive performance at the world-record breaking Suffolk Back Yard Ultra-marathon. Benchetrit et al. (2024) PLoS One. “This study indicates that cognitive performance is impaired when running an ultra-marathon which includes an element of sleep deprivation. In particular, reaction time and executive function deteriorated following race completion. The novel finding that good pre-race sleep quality was associated with a smaller decline in cognitive performance raises the possibility that improving sleep quality prior to a race could minimize these effects. Therefore, further research assessing the impact of a sleep quality intervention prior to a race could provide runners with an evidence-based strategy to improving race safety.” Observational study: Early morning sport scheduling is associated with poorer subjective sleep characteristics in British student-athletes. Wilson et al. (2024) Scand J Med Sci Sports. “ In summary, British student-athletes exhibit a high prevalence of poor sleep characteristics based on self-reported measures, aligning with previous findings in student-athletes from various nationalities. The sport and academic schedules occurring on weekdays, contributed to a pattern of social jetlag characterized by a phase advance in sleep timing and reduced sleep duration on weekdays compared to weekends. Logistic regression analyses revealed that the frequency of early morning training sessions (before 09:00) significantly predicted several sleep outcomes, even when controlling for participant characteristics. However, the frequency of late evening training sessions (after 21:00), as well as both academic-related and sport-related time demands, did not emerge as predictive factors for sleep outcomes. The key finding of this study was that an increased frequency of morning training sessions was predictive of poorer sleep outcomes. Therefore, it is important that sports coaches and administrators are aware of the impact of early morning sport on sleep, and the potentially harmful downstream effects of poor sleep on performance on the sports field and academic attainment in the classroom, in addition to general health and wellbeing. Where sporting activity in the morning before academic lessons cannot be avoided, it is important to design alternative interventions that are specific to the student-athlete population and help improve sleep outcomes within a challenging structure.”Athlete health (including mental health).
Scoping review: Inconsistencies in the perceived impact of the menstrual cycle on sport performance and in the prevalence of menstrual cycle symptoms: A scoping review of the literature. Oester et al. (2024) J Sci Med Sport. “The aim of this scoping review was to provide an overview of the findings related to the perceived impact of the menstrual cycle on athletic performance. However, similarly as to what has been reported in systematic reviews summarizing objective performance outcomes during different menstrual cycle phases, this review observed inconsistent findings between the different studies on perceived performance impacts, confirmed by the prediction interval calculated from a sample of the studies. Additionally, a large variability in the prevalence of menstrual cycle symptoms was reported in the different studies mainly due to the methodological differences. There is a general agreement in the research community that more research is needed, but this review supported the notion that higher-quality studies should be prioritized. To be able to compare research findings, future studies should adopt an approved terminology (e.g., PMS, heavy menstrual bleeding), provide a minimum level of education to participants to ensure they understand the questions correctly, and stratify the results according to contextual factors (e.g., hormonal contraceptive use, performance standard, sport category). Until further high-quality research is available, efforts should be put in place to provide education to athletes and coaches to increase the athletes' confidence to compete during every phase of their menstrual cycle.” Perspective: Athlete Mental Health and Wellbeing During the Transition into Elite Sport: Strategies to Prepare the System. Pilkington et al. (2024) Sports Med Open. “The transition into elite sport is associated with a range of stressors. If left unchecked or unaddressed, these may contribute to psychological distress or mental ill-health, which in turn may impact an athlete’s performance and ability to achieve their career goals. The youth athlete career phase is a particularly vulnerable period for mental ill-health, given the upheaval in many athletes’ physical environments, social relationships, training and lifestyle demands, and performance expectations. This paper seeks to address the balance in attention to transitions within elite sport, shining a light on the entry into elite sport settings, and the opportunities available via structured induction/onboarding programs. We argue that this career phase represents a key opportunity to provide athletes with the foundational components for supporting their mental health and building resilience to manage the demands and rigors of elite sport. We note that given the nascency of literature in this field, this framework will warrant revision when increased evidence is available about athletes’ mental health needs during the transition into elite sport, as well as evidence-based strategies for supporting mental health during this career transition.” Scoping study: Australian elite sport coaches' mental health literacy of eating disorders, orthorexia, and muscle dysmorphia in athletes: A qualitative study. Mitchell et al. (2024) Body Image. “This study aimed to qualitatively investigate Australian elite sport coaches’ mental health literacy of eating disorders and related conditions (orthorexia and muscle dysmorphia) in athletes. Coaches from weight-sensitive sports were sampled given these athletes have shown an increased risk of eating disorders. Four themes were generated in line with the research questions. These were coaches’ (1) knowledge of eating disorders and related conditions, (2) perceived facilitators to managing eating disorders, (3) perceived barriers to managing eating disorders, and (4) suggestions for future eating disorder education and training. Key findings suggested that coaches were aware of key eating disorder risk factors, however primarily identified eating disorders through observable weight loss and relied on nutrition-only education without considering the potential negative impacts (e.g., increased risk of developing orthorexia tendencies). Whilst coaches emphasised the helpfulness of referring to professionals and developing trusting relationships with their athletes, they described difficulties knowing how to communicate concerns to athletes and respond to denial. Given almost all coaches reported no prior eating disorder education, coaches displayed preference for interactive eating disorder training delivered by multidisciplinary experts. Future research may evaluate the effectiveness of these communication-based interventions. A longitudinal approach may investigate the long-term effects of training on coaches’ mental health literacy, including the need for and frequency of ‘refresher’ training as part of coaching accreditation.”Female athlete physiology and sex differences.
Case study: Low Energy Intake Leads to Body Composition and Performance Decrements in a Highly-Trained, Female Athlete: The WANDER (Woman's Activity and Nutrition during an Extensive Hiking Route) Case Study. Saenz et al. (2024) J Am Nutr Assoc. “In this case study, low energy intake led to decreased performance, body composition, and energy in a well-trained, Master class, female thru-hiker. This study underscores the critical need for adequate energy intake during thru-hiking, ultra-endurance athletic events, especially those with challenging environmental stressors. It also strongly supports the need for multidisciplinary approaches for optimising performance and reducing injury risks in ultra-endurance female athletes. There are several gaps in the literature remaining, particularly how low energy availability, and possibly Relative Energy Deficiency in Sport (RED-S), expresses itself in Master class athletes. Adequate energy intake is paramount to a successful thru-hike and more research, and robust assessments, on energy needs, sustainable and enjoyable dietary approaches, and optimal thru-hike-specific dietary counselling can provide much-needed insight into ways to reduce injury risks and support performance and recovery in thru-hiking athletes.”
And, to help you wash down the latest evidence, here's a snifter from my recent indulgence...
Thomas Solomon’s beer of the month.
Juicebag.
Bereta Brewing Co (Giarmata, Romania).
New England Hazy IPA.
6% ABV.
How would I describe this beer? 
“Cloudy and yellow to the eye. Piney and juicy to the nose. Mildly foamy but smooth on the tongue. Citrus and pine down the hatch with a mildly tangy and pleasant aftertaste. A pretty sessionable IPA.”
What is my Rating of Perceived beer Enjoyment? 
RP(be)E(r) = 7½ out of 10.
Access to education is a right, not a privilege:
Equality in education, health, and sustainability is important to me. I was lucky to be born into a social welfare system where higher education was free. Sadly, that is no longer true, so I want to provide access to running performance and sports nutrition education to folks from all walks of life. This nerd alert newsletter is just part of that offering. You can find more free educational resources from me, Thomas Solomon PhD, at veohtu.com.
Every day is a school day.
Empower yourself to train smart.
Think critically. Be informed. Stay educated.
Disclaimer: I occasionally mention brands and products but it is important to know that I am not affiliated with, sponsored by, an ambassador for, or receiving advertisement royalties from any brands. I have conducted biomedical research for which I have received research money from publicly-funded national research councils and medical charities, and also from private companies, including Novo Nordisk Foundation, AstraZeneca, Amylin, A.P. Møller Foundation, and Augustinus Foundation. I’ve also consulted for Boost Treadmills and Gu Energy on their research and innovation grant applications and I’ve provided research and science writing services for Examine — some of my articles contain links to information provided by Examine but I do not receive any royalties or bonuses from those links. These companies had no control over the research design, data analysis, or publication outcomes of my work. Any recommendations I make are, and always will be, based on my own views and opinions shaped by the evidence available. My recommendations have never and will never be influenced by affiliations, sponsorships, advertisement royalties, etc. The information I provide is not medical advice. Before making any changes to your habits of daily living based on any information I provide, always ensure it is safe for you to do so and consult your doctor if you are unsure.