-
1.
Nutrition and Endurance Sport - NED Infobite
BANT's scientific NED InfoBites are designed to provide key elements of the latest research using plain language. They provide quick overviews on particular health issues and nutrition topics for a speedy introduction to the science. Visually attractive and easily shareable with clients and social media followers.
2024
Abstract
Adequate nutrition is important for elite athletes, as nutrient availability influences energy expenditure, body composition, performance and exercise-induced immune responses. This NED Infobite includes science on the use of dietary nitrates, caffeine and probiotics as well as the impacts of time-restricted feeding.
-
2.
Urolithin A improves muscle strength, exercise performance, and biomarkers of mitochondrial health in a randomized trial in middle-aged adults.
Singh, A, D'Amico, D, Andreux, PA, Fouassier, AM, Blanco-Bose, W, Evans, M, Aebischer, P, Auwerx, J, Rinsch, C
Cell reports. Medicine. 2022;3(5):100633
-
-
-
-
Free full text
Plain language summary
A gradual decline in muscle mass and strength with aging is natural, however, environmental factors such as diet and exercise dictate the trajectory of the decline. Exercise and healthy nutrition are the primary interventions to prevent and manage age-associated decline in muscle health and metabolic diseases. This study was designed as a proof-of-concept investigation of the efficacy of long-term oral supplementation with urolithin A (UA) on physiological endpoints in middle-aged adults. This study is a randomised, double-blind, placebo-controlled study. An overweight middle-aged population with a high body mass index and average physical endurance was selected for the study. Results showed improved lower-body muscle strength in the hamstring skeletal muscle at both doses of UA. Furthermore, it positively impacted aerobic endurance and physical-performance measures such as walking distance. Authors conclude that supplementation with UA is safe and increases circulating levels of UA.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Mitochondrial dysfunction is associated with ageing and linked to deterioration of skeletal muscle and sarcopenia. Improving mitochondrial health may therefore help to improve muscle health as we age.
- Previous studies have demonstrated improvements in muscle endurance with long term UA intake in older adults (1) and the study by Singh et al. supports these findings in middle-aged adults.
- For middle-aged clients who are noticing a decline in muscle strength, exercise performance, or a general increase in fatigue, taking 500-1,000 mg UA daily for two to four months could lead to noticeable improvements in symptoms.
- The compounds from which UA is derived are also found in polyphenol-rich plant foods including pomegranates, berries and walnuts, therefore consuming these foods may be useful dietary additions for the same purpose.
- These findings are likely to be relevant for younger populations too, as mitophagy, which is part of the action of UA, contributes to the removal and recycling of dysfunctional mitochondria, allowing healthier intact mitochondria to take their place.
Evidence Category:
-
X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
-
B: Systematic reviews including RCTs of limited number
-
C: Non-randomized trials, observational studies, narrative reviews
-
D: Case-reports, evidence-based clinical findings
-
E: Opinion piece, other
Summary Review:
- Urolithin A (UA) is a microbiome metabolite – known as a postbiotic - of elligitannins and polyphenolic compounds found in some plant foods including pomegratate, berries and walnuts.
- In animal models, UA has previously been shown to have a range of potential health benefits involving induction of mitophagy and on mitochondrial function, as well as on disease states including osteoarthritis, inflammatory bowel disease, cardiovascular disease, and neurodegenerative disorders.
- The current study sought to establish proof-of-concept of the efficacy and safety of long-term UA supplementation on physiological endpoints in middle-aged adults.
- The primary outcome was peak power output and secondary outcomes included a range of clinical and physiological parameters linked to muscle strength, exercise tolerance and physical performance.
- The study tested UA in 500mg and 1000 mg doses against placebo in a 3-arm randomized-controlled trial in n= 88 subjects aged 40-64y who were healthy, overweight (BMI 25.0-34.9 kg/m2), sedentary, and who had a low VO2max at study inclusion. 79 subjects completed the study.
- Subjects were assessed at baseline, midpoint (2 months) and endpoint (4 months). In addition to the UA intervention, subjects were asked to maintain low physical activity status for the duration of the trial, and avoid pomegranates and supplements known to influence muscle performance (high protein, CoQ10m vitamin B3 or L-carnitine).
- Though a difference in peak power output (primary outcome) was not observed, muscle strength improved by up to c. 12% with 500 mg daily UA (p=0.027). With 1000 mg UA daily, aerobic endurance improved by up to 15% (p=0.03), gait speed increased by 7% (p=0.004), and in the 6-minute walk test subjects improved by 7% (p=0.008) and walked on average more than 30 additional meters, indicating a clinically meaningful difference in mobility.
- In addition, subjects in the UA groups had improved biomarkers of cellular health. With 1000 mg UA daily, inflammation was reduced (CRP, p<0.05; IFN-γ and TNF-α, both p<0.05). In addition, biomarkers of mitochondrial efficiency were also improved with 500 mg UA daily, Iing increased protein levels related to improved mitophagy, and expression of genes belonging to mitochondria.
- UA was deemed as safe and well tolerated at both 500 mg and 1000 mg doses for 4 months’ administration.
- A strength of the study was that the groups were balanced for all physiological parameters at baseline. However, the ratio of females was 2:1, and ethnicity was mainly western European. This may limit interpretation of the findings.
- All authors except one are either employees, board members or members of the scientific advisory board of Amazentis SA, who both manufacture Mitopure, the UA supplement used, and who funded this trial.
Clinical practice applications:
- Mitophagy is an important step in improving mitochondrial health. This study demonstrates the potential of UA to activate this pathway.
- In healthy middle-aged adults who are overweight or obese, sedentary and with low physical performance, oral UA supplementation at a sufficient dose and duration may:
- increase muscle strength
- increase mitophagy proteins in human skeletal muscle, as well as various other mitochondrial markers
- increase exercise performance and aerobic exercise
- be a valuable intervention to consider in clients who are suffering from mitochondrial dysfunction
Considerations for future research:
- This study was exploratory and the sample size for some of the outcomes was very small and inadequate to demonstrate true statistical significance. Future studies of similar design are needed to confirm the findings
- Nevertheless, the study was well-structured with carefully elaborated markers. It could be used as a template for future studies.
Abstract
Targeting mitophagy to activate the recycling of faulty mitochondria during aging is a strategy to mitigate muscle decline. We present results from a randomized, placebo-controlled trial in middle-aged adults where we administer a postbiotic compound Urolithin A (Mitopure), a known mitophagy activator, at two doses for 4 months (NCT03464500). The data show significant improvements in muscle strength (∼12%) with intake of Urolithin A. We observe clinically meaningful improvements with Urolithin A on aerobic endurance (peak oxygen oxygen consumption [VO2]) and physical performance (6 min walk test) but do not notice a significant improvement on peak power output (primary endpoint). Levels of plasma acylcarnitines and C-reactive proteins are significantly lower with Urolithin A, indicating higher mitochondrial efficiency and reduced inflammation. We also examine expression of proteins linked to mitophagy and mitochondrial metabolism in skeletal muscle and find a significant increase with Urolithin A administration. This study highlights the benefit of Urolithin A to improve muscle performance.
-
3.
The Effects of Menstrual Cycle Phase on Elite Athlete Performance: A Critical and Systematic Review.
Meignié, A, Duclos, M, Carling, C, Orhant, E, Provost, P, Toussaint, JF, Antero, J
Frontiers in physiology. 2021;12:654585
-
-
-
Free full text
Plain language summary
A one size fits all approach is impossible as athletes often respond differently to a given training stimulus, and the training load required for adaptation may differ significantly between sexes. Ideally, any individualized approach to preparation necessitates methods suited to each athlete’s needs in addition to technical and scientific expertise and resources. In fact, there is substantial interindividual variability leading to menstrual disturbance and it seems to be more frequent among elite athletes. This study is a review which focuses on research studies in elite athletes directly investigating the effects of menstrual cycle (MC) phases on performance parameters such as endurance or power resistance, symptoms linked to MC, ligament stiffness, decision making skills, and/or competitiveness (desire to compete and training motivation). Seven studies were included in the review with a total of 314 females. Results show that links between exercise performance and MC cannot be consistently identified from the present findings. The limited number of studies (including their study design) make these available studies challenging to transpose to the elite field. Authors conclude that there is a clear lack of evidence-based recommendations on training individualisation according to the menstrual cycle. Thus, solid conclusions regarding the impact of the MC for elite athletes cannot be formulated.
Abstract
Background: In elite athletes, training individualization is widely recommended to optimize competitive performance. Previous studies have evidenced the impact of hormonal fluctuations on different performance parameters among female athletes. While consideration of menstrual cycle (MC) phases as a parameter in training individualization strategies is necessary, systematic evidence identifying such impacts in elite athletes should be evaluated. Objective: Systematically review publications that have investigated the link between MC phases and performance in elite female athletes. The overarching aim is to identify whether a consensus across studies exists enabling evidence-based recommendations for training individualization depending on menstrual cycle phases. Methods: This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Three major scientific publication databases were searched from inception until November 3, 2020. Studies included focused on the influence of physiological or psychological parameters throughout at least one phase of the menstrual cycle of elite athletes. Results: A total of 780 search results were yielded and 26 references from a past bibliography were added manually. About 662 papers were reviewed of which 218 studies were assessed for eligibility. Of these, only seven (1%) precisely investigated the influence of a performance or physical parameter during at least one menstrual cycle phase. These seven studies included a total of 314 elite female participants (20.58 ± 1.91 years). Three used interviews, questionnaires or prospective analyses of reports. Four conducted several performance tests or included physical measures although only two performed tests during training or before/during competition. Among the seven studies, five performed hormonal testing through sampling of blood, saliva, or urine. The remaining relied on athletes' menstruation diaries. The current evidence suggests a variable association between menstrual cycle and a few performance-related outcomes, such as endurance or power resistance, ligament stiffness, decision making skills, psychology, or competitiveness. Conclusion: Different sports performance-related parameters are affected during the menstrual cycle among elite athletes, but the parameters themselves and the magnitude and the direction of the effects are inconclusive. Additional longitudinal and prospective studies to systematically monitor on-field performance parameters are urgently required in order to enable recommendations and training individualization in female elite athletes.
-
4.
Development of Maximal Dynamic Strength During Concurrent Resistance and Endurance Training in Untrained, Moderately Trained, and Trained Individuals: A Systematic Review and Meta-analysis.
Petré, H, Hemmingsson, E, Rosdahl, H, Psilander, N
Sports medicine (Auckland, N.Z.). 2021;51(5):991-1010
-
-
-
Free full text
-
Plain language summary
Athletes often require a combination of both strength and endurance in their chosen sport. As a result, a training programme which has both endurance and strength exercises within the same training period has become popular and is known as concurrent training. However, there are conflicting studies on the effectiveness of this way of training for athletic performance. This systematic review of 27 studies aimed to determine the overall effect of concurrent training on athletic performance based on the results of several studies and whether the time between training types could influence the effect. The results showed that leg press and squat exercises were negatively affected in trained individuals, but only if they were performed within the same training session. This was not evident in untrained and moderately trained individuals. It was concluded that in trained athletes, the performance of endurance and strength training within the same session can have a detrimental effect on lower body strength development. This study could be used by professionals to recommend that trained individuals separate endurance and strength training when increased strength is the goal.
Abstract
BACKGROUND The effect of concurrent training on the development of maximal strength is unclear, especially in individuals with different training statuses. OBJECTIVE The aim of this systematic review and meta-analysis study was to compare the effect of concurrent resistance and endurance training with that of resistance training only on the development of maximal dynamic strength in untrained, moderately trained, and trained individuals. METHODS On the basis of the predetermined criteria, 27 studies that compared effects between concurrent and resistance training only on lower-body 1-repetition maximum (1RM) strength were included. The effect size (ES), calculated as the standardised difference in mean, was extracted from each study, pooled, and analysed with a random-effects model. RESULTS The 1RM for leg press and squat exercises was negatively affected by concurrent training in trained individuals (ES = - 0.35, p < 0.01), but not in moderately trained ( - 0.20, p = 0.08) or untrained individuals (ES = 0.03, p = 0.87) as compared to resistance training only. A subgroup analysis revealed that the negative effect observed in trained individuals occurred only when resistance and endurance training were conducted within the same training session (ES same session = - 0.66, p < 0.01 vs. ES different sessions = - 0.10, p = 0.55). CONCLUSION This study demonstrated the novel and quantifiable effects of training status on lower-body strength development and shows that the addition of endurance training to a resistance training programme may have a negative impact on lower-body strength development in trained, but not in moderately trained or untrained individuals. This impairment seems to be more pronounced when training is performed within the same session than in different sessions. Trained individuals should therefore consider separating endurance from resistance training during periods where the development of dynamic maximal strength is prioritised.
-
5.
Effect of High-Intensity Interval Training, Moderate Continuous Training, or Guideline-Based Physical Activity Advice on Peak Oxygen Consumption in Patients With Heart Failure With Preserved Ejection Fraction: A Randomized Clinical Trial.
Mueller, S, Winzer, EB, Duvinage, A, Gevaert, AB, Edelmann, F, Haller, B, Pieske-Kraigher, E, Beckers, P, Bobenko, A, Hommel, J, et al
JAMA. 2021;325(6):542-551
-
-
-
Free full text
-
Plain language summary
Heart failure with preserved ejection fraction (HFpEF) is a condition in which the heart's lower left chamber is less able to pump blood due to stiffness. The prevalence of HFpEF is high among the elderly. Endurance exercise is known to increase peak oxygen consumption (Vo2). This prospective, randomised, controlled, three-armed, multi-centre trial aimed to understand the effects of endurance training in older people with HFpEF at 3 and 12 months. In this study, 180 sedentary patients with HFpEF were randomly assigned to high-intensity interval training, moderate continuous training, or control of home-based tele-guideline physical activity advice. The study found no statistically significant difference in changes in V̇o2 between high-intensity interval and moderate continuous training, and neither group met the clinically significant difference of 2.5 mL/kg/min compared with the guideline control. Diastolic function or natriuretic peptides did not change significantly in any group. Adherence level was lower among elderly patients, and there were serious adverse effects in patients with HFpEE. Healthcare professionals can use the findings of this study to understand the impact and adverse effects of endurance training at different intensities in patients with HFpEE.
Abstract
Importance: Endurance exercise is effective in improving peak oxygen consumption (peak V̇o2) in patients with heart failure with preserved ejection fraction (HFpEF). However, it remains unknown whether differing modes of exercise have different effects. Objective: To determine whether high-intensity interval training, moderate continuous training, and guideline-based advice on physical activity have different effects on change in peak V̇o2 in patients with HFpEF. Design, Setting, and Participants: Randomized clinical trial at 5 sites (Berlin, Leipzig, and Munich, Germany; Antwerp, Belgium; and Trondheim, Norway) from July 2014 to September 2018. From 532 screened patients, 180 sedentary patients with chronic, stable HFpEF were enrolled. Outcomes were analyzed by core laboratories blinded to treatment groups; however, the patients and staff conducting the evaluations were not blinded. Interventions: Patients were randomly assigned (1:1:1; n = 60 per group) to high-intensity interval training (3 × 38 minutes/week), moderate continuous training (5 × 40 minutes/week), or guideline control (1-time advice on physical activity according to guidelines) for 12 months (3 months in clinic followed by 9 months telemedically supervised home-based exercise). Main Outcomes and Measures: Primary end point was change in peak V̇o2 after 3 months, with the minimal clinically important difference set at 2.5 mL/kg/min. Secondary end points included changes in metrics of cardiorespiratory fitness, diastolic function, and natriuretic peptides after 3 and 12 months. Results: Among 180 patients who were randomized (mean age, 70 years; 120 women [67%]), 166 (92%) and 154 (86%) completed evaluation at 3 and 12 months, respectively. Change in peak V̇o2 over 3 months for high-intensity interval training vs guideline control was 1.1 vs -0.6 mL/kg/min (difference, 1.5 [95% CI, 0.4 to 2.7]); for moderate continuous training vs guideline control, 1.6 vs -0.6 mL/kg/min (difference, 2.0 [95% CI, 0.9 to 3.1]); and for high-intensity interval training vs moderate continuous training, 1.1 vs 1.6 mL/kg/min (difference, -0.4 [95% CI, -1.4 to 0.6]). No comparisons were statistically significant after 12 months. There were no significant changes in diastolic function or natriuretic peptides. Acute coronary syndrome was recorded in 4 high-intensity interval training patients (7%), 3 moderate continuous training patients (5%), and 5 guideline control patients (8%). Conclusions and Relevance: Among patients with HFpEF, there was no statistically significant difference in change in peak V̇o2 at 3 months between those assigned to high-intensity interval vs moderate continuous training, and neither group met the prespecified minimal clinically important difference compared with the guideline control. These findings do not support either high-intensity interval training or moderate continuous training compared with guideline-based physical activity for patients with HFpEF. Trial Registration: ClinicalTrials.gov Identifier: NCT02078947.
-
6.
Combined Effects of Citrulline Plus Nitrate-Rich Beetroot Extract Co-Supplementation on Maximal and Endurance-Strength and Aerobic Power in Trained Male Triathletes: A Randomized Double-Blind, Placebo-Controlled Trial.
Burgos, J, Viribay, A, Fernández-Lázaro, D, Calleja-González, J, González-Santos, J, Mielgo-Ayuso, J
Nutrients. 2021;14(1)
-
-
-
Free full text
Plain language summary
Triathletes often resort to taking ergogenic supplements to boost their performance as diet alone may not be sufficient to meet their physical demands. Previous studies have shown the ergogenic effects of L-citrulline (CIT) and beetroot extract (BR) in improving aerobic and anaerobic metabolism and boosting sports performance. In addition, both BR and CIT contain nitric oxide, which is known to enhance athletic performance, neuromuscular strength and endurance. This randomised, double-blinded, placebo-controlled trial for nine weeks on thirty-two male trained triathletes evaluated the effect of oral co-supplementation of 3g/day of CIT with 2.1g/day of BR on sports performance. The researchers found that oral co-supplementation of CIT plus BR for nine weeks improved maximal strength, endurance strength and performance among amateur trained male triathletes. Long-term, extensive, robust studies are required to further explore the effects of co-supplementation. Nevertheless, Healthcare and nutrition practitioners can use the findings of this study to understand the ergogenic effects of CIT and BR co-supplementation and consider co-supplementation during phases of intensive practice to boost athletic performance.
Abstract
Citrulline (CIT) and nitrate-rich beetroot extract (BR) are ergogenic aids and nitric oxide (NO) precursors. In addition, both supplements seem to have other actions at the level of muscle metabolism that can benefit strength and aerobic power performance. Both supplements have been studied in numerous investigations in isolation. However, scientific evidence combining both supplements is scarce, and to the best of the authors' knowledge, there is no current study of endurance athletes. Therefore, the main purpose of this study was to determine the effect of 9 weeks of CIT plus BR supplementation on maximal and endurance-strength performance and aerobic power in male triathletes. This study was a randomized double-blind, placebo-controlled trial where participants (n = 32) were randomized into four different groups: placebo group (PLG; n = 8), CIT plus BR group (CIT- BRG; 3 g/kg/day of CIT plus 3 mg/kg/day of nitrates (NO3-); n = 8), CIT group (CITG; 3 g/kg/day; n = 8) and BR group (BRG; 3 mg/kg/day of NO3-; n = 8). Before (T1) and after 9 weeks (T2), four physical condition tests were carried out in order to assess sport performance: the horizontal jump test (HJUMP), handgrip dynamometer test, 1-min abdominal tests (1-MAT) and finally, the Cooper test. Although, no significant interactions (time × supplementation groups) were found for the strength tests (p > 0.05), the CIT- BRG supplementation presented a trend on HJUMP and 1-MAT tests confirmed by significant increase between two study moments in CIT-BRG. Likewise, CIT-BRG presented significant interactions in the aerobic power test confirmed by this group's improve estimated VO2max during the study with respect to the other study groups (p = 0.002; η2p = 0.418). In summary, supplementing with 3 g/day of CIT and 2.1 g/day of BR (300 mg/day of NO3-) for 9 weeks could increase maximal and endurance strength. Furthermore, when compared to CIT or BR supplementation alone, this combination improved performance in tests related to aerobic power.
-
7.
Effects of Attentional Focus on Muscular Endurance: A Meta-Analysis.
Grgic, J, Mikulic, P
International journal of environmental research and public health. 2021;19(1)
-
-
-
Free full text
Plain language summary
For over 20 years, the effects of attentional focus on motor learning have been explored. Several muscular qualities are important when discussing resistance exercise, including muscular endurance. The aim of this study was to perform a meta-analysis examining the effects of external focus vs. internal focus vs. control on muscular endurance. This study is a meta-analysis of five studies. The pooled number of participants among the included studies was 141 (24 females and 117 males). Results indicate that adopting an external focus of attention enhances muscular endurance. These performance-enhancing effects of external focus were found when comparing both with an internal focus and control condition. However, there was no significant difference between the internal focus and control conditions. Authors conclude that individuals should use an external focus of attention for acute enhancement of muscular endurance.
Abstract
Several studies explored the effects of attentional focus on resistance exercise, but their analysed outcomes most commonly involved surface electromyography variables. Therefore, the effects of attentional focus on resistance exercise performance remain unclear. The aim of this review was to perform a meta-analysis examining the acute effects of external focus vs. internal focus vs. control on muscular endurance. Five databases were searched to find relevant studies. The data were pooled in a random-effects meta-analysis. In the analysis for external vs. internal focus of attention, there were seven comparisons with 14 study groups. In the analyses for external focus vs. control and internal focus vs. control, there were six comparisons with 12 study groups. An external focus of attention enhanced muscular endurance when compared with an internal focus (Cohen's d: 0.58; 95% confidence interval (CI): 0.34 and 0.82) and control (Cohen's d: 0.42; 95% CI: 0.08 and 0.76). In the analysis for internal focus vs. control, there was no significant difference between the conditions (Cohen's d: -0.19; 95% CI: -0.45 and 0.07). Generally, these results remained consistent in the subgroup analyses for upper-body vs. lower-body exercises. From a practical perspective, the results presented in this review suggest that individuals should use an external focus of attention for acute enhancement of muscular endurance.
-
8.
Effects of a 6 Week Low-Dose Combined Resistance and Endurance Training on T Cells and Systemic Inflammation in the Elderly.
Despeghel, M, Reichel, T, Zander, J, Krüger, K, Weyh, C
Cells. 2021;10(4)
-
-
-
Free full text
Plain language summary
As age advances, a gradual deterioration of immune function happens termed Immunosenescence, where different components of the immune system make a behavioural shift towards gradual decline. Immune ageing is characterized by changes in the ratio of naive memory T cells and CD4:CD8 and is associated with inflammatory cytokine production, which accelerates inflammatory ageing. This randomised controlled trial aimed to examine the effect of low-dose combined resistance and endurance training on the ageing immune system and inflammation in elderly subjects. Thirty participants (between the ages of 65 and 75) took part in a controlled low-threshold and care-oriented combined resistance and endurance training program for six weeks. This study showed an increase in CD4:CD8 ratio, decrease in low-grade inflammation and an improvement in strength capacity denoting improved immunosenescence and inflammaging among elderly participants. However, the study was conducted on a small sample for a short period. Therefore, robust long-term studies are required to elucidate further positive effects of different levels of physical activities in the elderly. Healthcare professionals can use these findings to understand how exercise influences immunosenescence and inflammation in the ageing body.
Abstract
With increasing age, the immune system undergoes a remodeling process, affecting the shift of T cell subpopulations and the development of chronic low-grade inflammation. Clinically, this is characterized by increased susceptibility to infections or development of several diseases. Since lifestyle factors can play a significant role in reducing the hallmarks of immune aging and inflammation, we investigated the effect of a 6 week low-dose combined resistance and endurance training program. Forty participants (70.3 ± 5.0 years) were randomly assigned to either a training (TG) or control group (CG) and performed a controlled low-threshold and care-oriented 6-week-long combined resistance and endurance training program. Changes in anthropometrics as well as strength capacity were measured. In subgroups of TG and CG, T cells and their subpopulations (CD4+, CD8+, naïve, central, effector memory, T-EMRA) were analyzed by flow cytometry. The changes of various plasma cytokines, chemokines, growth factors and adipokines were analyzed by luminex assays. The exercise program was followed by an increase in strength capacities. Participants of TG showed an increase of the CD4+/CD8+ T cell ratio over time (p < 0.05). Significant decreases in systemic levels of interleukin (IL-) 6, IL-8, IL-10 and vascular endothelial growth factor (VEGF) (p < 0.05) were observed for participants of TG over time. Even short-term and low-threshold training can reduce some of the hallmarks of immune aging in elderly and thus could be beneficial to stimulate immunity. The specific characteristics of the program make it easily accessible to older people, who may benefit in the longer term in terms of their immunocompetence.
-
9.
Monitoring and adapting endurance training on the basis of heart rate variability monitored by wearable technologies: A systematic review with meta-analysis.
Düking, P, Zinner, C, Trabelsi, K, Reed, JL, Holmberg, HC, Kunz, P, Sperlich, B
Journal of science and medicine in sport. 2021;24(11):1180-1192
-
-
-
Free full text
Plain language summary
Changes in cardiorespiratory fitness and endurance performance in response to different predefined training programmes of a specific duration (e.g., 4 weeks) vary widely – from positive, none or even negative adaptations. The aim of this study was to identify relevant scientific literature to compare the various effects of predefined training, with training guided by variations in heart-rate variability (HRV) regarding performance or physiological parameters. This study is a systematic review and meta-analysis of eight studies with a total of nine interventions. Results indicate that training that was adapted in response to changes in HRV, in comparison to predefined endurance training, resulted in a significantly greater medium improvement in submaximal physiological parameters. Furthermore, HRV-based training is more associated with fewer negative and a larger proportion of positive responders. Authors conclude that factors other than training, including psychological stress related to work or academic studies, exert an impact on HRV and, thus, definitive conclusions cannot be drawn on what caused the changes in HRV.
Abstract
OBJECTIVES To systematically perform a meta-analysis of the scientific literature to determine whether the outcomes of endurance training based on heart rate variability (HRV) are more favorable than those of predefined training. DESIGN Systematic review and meta-analysis. METHODS PubMed and Web of Science were searched systematically in March of 2020 using keywords related to endurance, the ANS, and training. To compare the outcomes of HRV-guided and predefined training, Hedges' g effect size and associated 95% confidence intervals were calculated. RESULTS A total of 8 studies (198 participants) were identified comprising 9 interventions involving a variety of approaches. Compared to predefined training, most HRV-guided interventions included fewer moderate- and/or high-intensity training sessions. Fixed effects meta-analysis revealed a significant medium-sized positive effect of HRV-guided training on submaximal physiological parameters (g = 0.296, 95% CI 0.031 to 0.562, p = 0.028), but its effects on performance (g = 0.079, 95% CI -0.050 to 0.393, p = 0.597) and V̇O2peak (g = 0.171, 95% CI -0.213 to 0.371, p = 0.130) were small and not statistically significant. Moreover, with regards to performance, HRV-guided training was associated with fewer non-responders and more positive responders. CONCLUSIONS In comparison to predefined training, HRV-guided endurance training had a medium-sized effect on submaximal physiological parameters, but only a small and non-significant influence on performance and V̇O2peak. There were fewer non-responders regarding performance with HRV-based training.
-
10.
The Effect of Dietary Supplements on Endurance Exercise Performance and Core Temperature in Hot Environments: A Meta-analysis and Meta-regression.
Peel, JS, McNarry, MA, Heffernan, SM, Nevola, VR, Kilduff, LP, Waldron, M
Sports medicine (Auckland, N.Z.). 2021;51(11):2351-2371
-
-
-
Free full text
-
Plain language summary
Physical capacity is markedly impaired with increasing ambient temperature and humidity, leading to thermoregulatory strain and early onset fatigue, for a variety of physiological reasons. The aim of this study was to investigate the effects of selected dietary supplements on endurance performance in the heat, as well as the associated core temperature responses. This study is a meta-analysis of 25 studies of which 25, 24 and 20 papers were included in the exercise performance, end core temperature and submaximal core temperature analyses, respectively. Results indicate that dietary supplementation has a trivial, significant overall positive effect on endurance exercise performance in the heat. Namely: - Amino acids appear to provide a greater performance benefit during exercise in the heat, but the effects were often statistically insignificant. - Branched-chain amino acids offered the most consistent, yet small, performance effect. - Taurine has both the greatest performance and thermoregulatory effect sizes of any of the supplements. Authors conclude that current dietary supplementation guidelines for exercise in hot environments must be adapted and require further detail for sports and tactical personnel.
Abstract
BACKGROUND The ergogenic effects of dietary supplements on endurance exercise performance are well-established; however, their efficacy in hot environmental conditions has not been systematically evaluated. OBJECTIVES (1) To meta-analyse studies investigating the effects of selected dietary supplements on endurance performance and core temperature responses in the heat. Supplements were included if they were deemed to: (a) have a strong evidence base for 'directly' improving thermoneutral endurance performance, based on current position statements, or (b) have a proposed mechanism of action that related to modifiable factors associated with thermal balance. (2) To conduct meta-regressions to evaluate the moderating effect of selected variables on endurance performance and core temperature responses in the heat following dietary supplementation. METHODS A search was performed using various databases in May 2020. After screening, 25 peer-reviewed articles were identified for inclusion, across three separate meta-analyses: (1) exercise performance; (2) end core temperature; (3) submaximal core temperature. The moderating effect of several variables were assessed via sub-analysis and meta-regression. RESULTS Overall, dietary supplementation had a trivial significant positive effect on exercise performance (Hedges' g = 0.18, 95% CI 0.007-0.352, P = 0.042), a trivial non-significant positive effect on submaximal core temperature (Hedges' g = 0.18, 95% CI - 0.021 to 0.379, P = 0.080) and a small non-significant positive effect on end core temperature (Hedges' g = 0.20, 95% CI - 0.041 to 0.439, P = 0.104) in the heat. There was a non-significant effect of individual supplements on exercise performance (P = 0.973) and submaximal core temperature (P = 0.599). However, end core temperature was significantly affected by supplement type (P = 0.003), which was attributable to caffeine's large significant positive effect (n = 8; Hedges' g = 0.82, 95% CI 0.433-1.202, P < 0.001) and taurine's medium significant negative effect (n = 1; Hedges' g = - 0.96, 95% CI - 1.855 to - 0.069, P = 0.035). CONCLUSION Supplements such as caffeine and nitrates do not enhance endurance performance in the heat, with caffeine also increasing core temperature responses. Some amino acids might offer the greatest performance benefits in the heat. Exercising in the heat negatively affected the efficacy of many dietary supplements, indicating that further research is needed and current guidelines for performance in hot environments likely require revision.