Primum non nocere; It’s time to consider altitude training as the medical intervention it actually is!

Sleep is one of the most important aspects of recovery, and is known to be severely affected by hypoxia. The present position paper focuses on sleep as a strong moderator of the altitude training-response. Indeed, the response to altitude training is highly variable, it is not a fixed and classifiable trait, rather it is a state that is determined by multiple factors (e.g., iron status, altitude dose, pre-intervention hemoglobin mass, training load, and recovery). We present an overview of evidence showing that sleep, and more specifically the prolonged negative impact of altitude on the nocturnal breathing pattern, affecting mainly deep sleep and thus the core of physiological recovery during sleep, could play an important role in intra- and interindividual variability in the altitude training-associated responses in professional and recreational athletes. We conclude our paper with a set of suggested recommendations to customize the application of altitude training to the specific needs and vulnerabilities of each athlete (i.e., primum non nocere). Several factors have been identified (e.g., sex, polymorphisms in the TASK2/KCNK5, NOTCH4 and CAT genes and pre-term birth) to predict individual vulnerabilities to hypoxia-related sleep-disordered breathing. Currently, polysomnography should be the first choice to evaluate an individual’s predisposition to a decrease in deep sleep related to hypoxia. Further interventions, both pharmacological and non-pharmacological, might alleviate the effects of nocturnal hypoxia in those athletes that show most vulnerable

Cycling on a bike desk positively influences cognitive performance

Purpose: cycling desks as a means to reduce sedentary time in the office has gained interest as excessive sitting has been associated with several health risks. However, the question rises if people will still be as efficient in performing their desk-based office work when combining this with stationary cycling. Therefore, the effect of cycling at 30% Wmax on typing, cognitive performance and brain activity was investigated. Methods: After two familiarisation sessions, 23 participants performed a test battery [typing test, Rey auditory verbal learning test (RAVLT), Stroop test and Rosvold continuous performance test (RCPT)] with electroencephalography recording while cycling and sitting on a conventional chair. Results: Typing performance, performance on the RAVLT and accuracy on the Stroop test and the RCPT did not differ between conditions. Reaction times on the Stroop test and the RCPT were shorter while cycling relative to sitting (p < 0.05). N200, P300, N450 and conflict SP latency and amplitude on the Stroop test and N200 and P300 on the RCPT did not differ between conditions. Conclusions: This study showed that typing performance and short-term memory are not deteriorated when people cycle at 30% Wmax. Furthermore, cycling had a positive effect on response speed across tasks requiring variable amounts of attention and inhibition

A caffeine-maltodextrin mouth rinse counters mental fatigue

Introduction: Mental fatigue is a psychobiological state caused by prolonged periods of demanding cognitive activity that has negative implications on many aspects in daily life. Caffeine and carbohydrate ingestion have been shown to be able to reduce these negative effects of mental fatigue. Intake of these substances might however be less desirable in some situations (e.g., restricted caloric intake, Ramadan). Rinsing caffeine or glucose within the mouth has already been shown to improve exercise performance. Therefore, we sought to evaluate the effect of frequent caffeine-maltodextrin (CAF-MALT) mouth rinsing on mental fatigue induced by a prolonged cognitive task. Methods: Ten males (age 23?±?2 years, physical activity 7.3?±?4.3 h/week, low CAF users) performed two trials. Participants first completed a Flanker task (3 min), then performed a 90-min mentally fatiguing task (Stroop task), followed by another Flanker task. Before the start and after each 12.5% of the Stroop task (eight blocks), subjects received a CAF-MALT mouth rinse (MR: 0.3 g/25 ml CAF: 1.6g/25 ml MALT) or placebo (PLAC: 25 ml artificial saliva). Results: Self-reported mental fatigue was lower in MR (p?=?0.017) compared to PLAC. Normalized accuracy (accuracy first block?=?100%) was higher in the last block of the Stroop in MR (p?=?0.032) compared to PLAC. P2 amplitude in the dorsolateral prefrontal cortex (DLPFC) decreased over time only in PLAC (p?=?0.017). Conclusion: Frequent mouth rinsing during a prolonged and demanding cognitive task reduces mental fatigue compared to mouth rinsing with artificial saliva

Impact of a carbohydrate mouth rinse on corticomotor excitability after mental fatigue in healthy college-aged subjects

Mental Fatigue (MF) has been associated with reduced physical performance but the mechanisms underlying this result are unclear. A reduction in excitability of the corticomotor system is a way mental fatigue could negatively impact physical performance. Carbohydrate (CHO) mouth rinse (MR) has been shown to increase corticomotor excitability. The purpose of this study was to determine if CHO MR impacts corticomotor excitability after MF. Fifteen subjects (nine females, six males; age = 23 ± 1 years; height = 171 ± 2 cm; body mass = 69 ± 3 kg; BMI = 23.8 ± 0.7) completed two sessions under different MR conditions (Placebo (PLAC), 6.4% glucose (CHO)) separated by at least 48 h and applied in a double-blinded randomized fashion. Motor-evoked potential (MEP) of the left first dorsal interosseous (FDI) was determined by transcranial magnetic stimulation (TMS) before and after MF. Perceived MF was recorded before and after the MF task using a 100 mm visual analog scale (VAS). MF was greater following PLAC (+30.4 ± 4.0 mm) than CHO (+19.4 ± 3.9 mm) ( = 0.005). MEP was reduced more following PLAC (-16.6 ± 4.4%) than CHO (-3.7 ± 4.7%) ( < 0.001). CHO MR was successful at attenuating the reduction in corticomotor excitability after MF. Carbohydrate mouth rinse may be a valuable tool at combating the negative consequences of mental fatigue

Effects of Mental Fatigue on Endurance Performance in the Heat

PURPOSE: Mental fatigue is a psychobiological state caused by prolonged periods of demanding cognitive activity and has been observed to decrease time-trial (TT) endurance performance by ~3,5% in normal ambient temperatures. Recently it has been suggested that heat may augment the negative effect of mental fatigue on cognitive performance, raising the question whether it may also amplify the effect of mental fatigue on TT-performance. METHODS: In 30 °C and 30% relative humidity, ten endurance-trained male athletes (Age: 22 ± 3 y; Wmax: 332 ± 41 W) completed two experimental conditions: intervention (I; 45-min Stroop task) and control (C; 45-min documentary). Pre and post intervention/control, cognitive performance was followed up with a 5-min Flanker task. Thereafter subjects cycled for 45 min at a fixed pace equal to 60%-Wmax, immediately followed by a self-paced TT in which they had to produce a fixed amount of work (equal to cycling 15 min at 80%-Wmax) as fast as possible. RESULTS: Self-reported mental fatigue was significantly higher after I compared to C (P<0.05). Moreover electroencephalographic measures also indicated the occurrence of mental fatigue during the Stroop (P<0.05). TT-time did not differ between conditions (I: 906 ± 30 s, C: 916 ± 29 s). Throughout exercise, physiological (heart rate, blood lactate, core and skin temperature) and perceptual measures (perception of effort and thermal sensation) were not affected by mental fatigue. CONCLUSION: No negative effects of mild mental fatigue were observed on performance and the physiological and perceptual responses to endurance exercise in the heat. Most plausibly mild mental fatigue does not reduce endurance performance when the brain is already stressed by a hot environment

The impact of the COVID-19 lockdown on human psychology and physical activity; a space analogue research perspective

Introduction Astronauts will encounter isolated, confined and extreme (ICE) conditions during future missions, and will have to be able to adapt. Until recently, however, few places on Earth could serve as acceptable space analogues (i.e., submarine and polar regions). The coronavirus disease-2019 (COVID-19)-related lockdowns around the globe provided a good opportunity to obtain more comprehensive datasets on the impact of prolonged isolation on human functioning in a very large sample. Methods Seven hundred forty-eight individuals (Belgium 442, Spain 183, Germany 50, Italy 50, US 23; Mean age +/- SD: 41 +/- 14 years, with an age range of 18-83 years; 66% women) filled out an online survey assessing the impact of the COVID-lockdown on psychological, exercise and general health variables a first time near the beginning of the initial lockdown (hereafter 'T1'; 24 +/- 13 days after the start of the first lockdown; i.e., 3 weeks after the start of the first lockdown) and a second time a couple of weeks thereafter (hereafter 'T2'; 17 +/- 5 days after the first online survey; i.e., 6 weeks after the start of the first lockdown). Results From T1 to T2 an improvement of subjective sleep quality was observed (P = 0.003), that was related to an increase in subjective sleep efficiency and a decrease in sleep latency and disturbance (P <= 0.013). Weekly sitting time decreased, and the weekly amount of moderate and vigorous physical activity increased from T1 to T2 (P <= 0.049). No differences from T1 to T2 were observed in terms of mood, loneliness and state anxiety. A lower amount of sitting time was significantly correlated with improved subjective sleep quality (r = 0.096, P = 0.035) and with an increased amount of moderate (r = -0.126, P = 0.005) and vigorous (r = -0.110, P = 0.015) physical activity. Conclusion Compared to 3 weeks into the first COVID-imposed lockdown, 6-weeks after the start of the first COVID-imposed lockdown, physical activity and subjective sleep scores were positively impacted. The present, large sample size study further confirms exercise as a worthwhile countermeasure to psycho-physiological deconditioning during confinement

The Effects of Mental Fatigue on Physical Performance: A Systematic Review.

Background: Mental fatigue is a psychobiological state caused by prolonged periods of demanding cognitive activity. It has recently been suggested that mental fatigue can affect physical performance. Objective: Our objective was to evaluate the literature on impairment of physical performance due to mental fatigue and to create an overview of the potential factors underlying this effect. \ud Methods: Two electronic databases, PubMed and Web of Science (until 28 April 2016), were searched for studies designed to test whether mental fatigue influenced performance of a physical task or influenced physiological and/or perceptual responses during the physical task. Studies using short (<30 min) self-regulatory depletion tasks were excluded from the review. Results: A total of 11 articles were included, of which six were of strong and five of moderate quality. The general finding was a decline in endurance performance (decreased time to exhaustion and self-selected power output/velocity or increased completion time) associated with a higher than normal perceived exertion. Physiological variables traditionally associated with endurance performance (heart rate, blood lactate, oxygen uptake, cardiac output, maximal aerobic capacity) were unaffected by mental fatigue. Maximal strength, power, and anaerobic work were not affected by mental fatigue. Conclusion: The duration and intensity of the physical task appear to be important factors in the decrease in physical performance due to mental fatigue. The most important factor responsible for the negative impact of mental fatigue on endurance performance is a higher perceived exertion

Bridging exercise science, cognitive psychology, and medical practice: Is "cognitive fatigue" a remake of "the emperor's new clothes"?

Fatigue is such a multifaceted construct it has sprouted specific research fields and experts in domains as different as exercise physiology, cognitive psychology, human factors and engineering, and medical practice. It lacks a consensus definition: it is an experimental concept, a symptom, a risk, a cause (e.g. of performance decrement) and a consequence (e.g. of sleep deprivation). This fragmentation of knowledge leads to slower dissemination of novel insights, and thus to a poorer research. Indeed, what may seem as a novel result in one field, may very well be old news in another, hence leading to this "innovation" being a scientific equivalent to the emperor's new clothes. The current paper aims to describe the common denominator in the different areas of expertise where fatigue is investigated. Indeed, rather than focusing on the differences in semantics and conceptualization, we hope that identifying common concepts may be inductive of easier multidisciplinary research. Considering the vastness of fatigue research in all areas identified as relevant-cognitive science, exercise physiology, and medical practice, this analysis has not the ambition to be an exhaustive review in all domains. We have reviewed the fatigue concepts and research in these areas and report the ones that are used to describe the proposed common model to be further investigated. The most promising common feature to cognitive science, exercise physiology and clinical practice is the notion of "perceived effort." This allows to account for interindividual differences, as well as for the situational variations in fatigue. It is applicable to both mental and physical constructs. It integrates motivational and emotional dimensions. It overcomes current polemics in various research fields, and it does not draw on any semantic ambiguity. We thus suggest a new model of fatigue and performance, whether this performance is mental or physical; and whether it is in a clinical range or relates to optimal functioning.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Prefrontal cortex oxygenation during endurance performance: A systematic review of functional near-infrared spectroscopy studies.

A myriad of factors underlie pacing-/exhaustion-decisions that are made during whole-body endurance performance. The prefrontal cortex (PFC) is a brain region that is crucial for decision-making, planning, and attention. PFC oxygenation seems to be a mediating factor of performance decisions during endurance performance. Nowadays, there is no general overview summarizing the current knowledge on how PFC oxygenation evolves during whole-body endurance performance and whether this is a determining factor. Three electronic databases were searched for studies related to the assessment of PFC oxygenation, through near-IR spectroscopy (NIRS), during endurance exercise. To express PFC oxygenation, oxygenated (HbO ) and deoxygenated hemoglobin (HHb) concentrations were the primary outcome measures. Twenty-eight articles were included. Ten articles focused on assessing prefrontal oxygenation through a maximal incremental test (MIT) and 18 focused on using endurance tasks at workloads ranging from low intensity to supramaximal intensity. In four MIT studies measuring HbO , an increase of HbO was noticed at the respiratory compensation point (RCP), after which it decreased. HbO reached a steady state in the four studies and increased in one study until exhaustion. All studies found a decrease or steady state in HHb from the start until RCP and an increase to exhaustion. In regard to (non-incremental) endurance tasks, a general increase in PFC oxygenation was found while achieving a steady state at vigorous intensities. PCF deoxygenation was evident for near-to-maximal intensities at which an increase in oxygenation and the maintenance of a steady state could not be retained. : MIT studies show the presence of a cerebral oxygenation threshold (ThCox) at RCP. PFC oxygenation increases until the RCP threshold, thereafter, a steady state is reached and HbO declines. This study shows that the results obtained from MIT are transferable to non-incremental endurance exercise. HbO increases during low-intensity and moderate-intensity until vigorous-intensity exercise, and it reaches a steady state in vigorous-intensity exercise. Furthermore, ThCox can be found between vigorous and near-maximal intensities. During endurance exercise at near-maximal intensities, PFC oxygenation increases until the value exceeding this threshold, resulting in a decrease in PFC oxygenation. Future research should aim at maintaining and improving PFC oxygenation to help in improving endurance performance and to examine whether PFC oxygenation has a role in other performance-limiting factors. [Abstract copyright: Copyright © 2021 De Wachter, Proost, Habay, Verstraelen, Díaz-García, Hurst, Meeusen, Van Cutsem and Roelands.