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Limited scientific evidence suggests that physical activity is directly related to cognitive performance in patients with chronic fatigue syndrome (CFS). To date, no other study has examined the direct relationship between cognitive performance and physical fitness in these patients. This study examined whether cognitive performance and physical fitness are associated in female patients with CFS and investigated the association between cognitive performance and physical activity level (PAL) in the same study sample. We hypothesized that patients who performed better on cognitive tasks would show increased PALs and better performance on physical tests. The study included 31 women with CFS and 13 healthy inactive women. Participants first completed three cognitive tests. Afterward, they undertook a test to determine their maximal handgrip strength, performed a bicycle ergometer test, and were provided with an activity monitor. In patients with CFS, lower peak oxygen uptake and peak heart rate were associated with slower psychomotor speed (p < 0.05). Maximal handgrip strength was correlated with working memory performance (p < 0.05). Both choice and simple reaction time were lower in patients with CFS relative to healthy controls (p < 0.05 and p < 0.001, respectively). In conclusion, physical fitness, but not PAL, is associated with cognitive performance in female patients with CFS.

INTRODUCTION: Cognitive performance is crucial during military operations. It is suggested that impaired cognitive performance accounts for most of the accidents during training courses and actual battle. There is a need to define when soldiers' operational readiness becomes impaired. The objective of this systematic review was to investigate the effects of sustained military operations (SUSOPS) on vigilance, reaction time, working memory, and reasoning in order to select good indicators for performance impairment. METHODS: A systematic literature search was performed using publicly accessible databases (IngentaConnect, PubMed, Science Direct, and Defense Technical Information Center online) that were screened until July 2015. Keywords were military, sustained operations, (cognitive) performance, soldier, and training. RESULTS: Only 7 out of 589 studies met the inclusion criteria. Selected studies were difficult to compare due to different method-ologies, cognitive tasks, and military courses. Vigilance, reaction time, and working memory were affected after only a few hours, showing severe impairment. They are linearly related to military stress up to 80 h of SUSOPS. These three indicators needed little recovery time to return to baseline levels. After more than 80 h of SUSOPS, no significant impairments of those indicators were observed. Reasoning becomes impaired after high stress levels of relatively short duration and can remain affected after more than 80 h of SUSOPS. DISCUSSION: Vigilance, reaction time, and working memory are affected after only a few hours while little recovery time is needed. For reasoning to return to baseline values, longer recovery is needed than the time available during SUSOPS. [ABSTRACT FROM AUTHOR]

Aim: To examine the isolated and combined effects of severe hypoxia and a mild thermal challenge on performance, physiological measures, cognition, and serum brain-derived neurotrophic factor (BDNF).Methods: Nine trained male athletes (age: 23 ± 3 years; W max: 333 ± 45 W) completed four experimental trials (CON: 15 °C/0 m, ALT: 15 °C/3800 m, TEMP: 25 °C/0 m, ALT + TEMP: 25 °C/3800 m) in a double blind, randomized, cross-over design. Subjects cycled for 30 min in a self-paced test starting at 75% W max, their goal was to 'perform as much work as possible in 30 min.' Power output, heart rate, blood lactate, pulse oximetry, core and skin temperature, thermal sensation, ratings of perceived exertion, reaction time (RT), and BDNF were assessed.Results: The amount of work produced in 30 min was reduced by temperature (F(1,8) = 7.1; p = 0.029; 360 ± 19 kJ in 15 °C; 344 ± 18 kJ in 25 °C) and altitude (F(1,8) = 94.2; p < 0.001; 427 ± 24 kJ at sea level; 277 ± 15 kJ at altitude), yet there was no interaction effect. Altitude increased mean RT (F(1,8) = 8.0; p = 0.022; 281.9 ± 9.4 ms at sea level; 289.3 ± 10.0 ms at altitude) and RT variability (F(1,8) = 8.5; p = 0.020; 44 ± 3 ms at sea level: 50 ± 4 ms at altitude). Exercise increased BDNF (F(1,8) = 15.2; p = 0.005; PRE: 21.8 ± 1.3 ng/mL; POST: 26.5 ± 2.1 ng/mL).Conclusion: Exercise capacity was significantly reduced due to an increase in altitude (3800 m; -34.3%) or a 10 °C increase in ambient temperature (-3.2%). The combination of both stressors showed to be additive (-38.0 %). Altitude induced an increase in RT and RT variability presenting a deterioration in cognitive functioning during acute hypoxia. Exercise significantly increased BDNF, but no effect of altitude on the BDNF concentration was observed. [ABSTRACT FROM AUTHOR]

Background. Both good physical and cognitive functioning have a positive influence on the execution of activities of daily living. Patients with chronic fatigue syndrome (CFS) as well as patients with fibromyalgia have marked cognitive deficits. Furthermore, a good physical and functional health status may have a positive impact on a variety of cognitive skills--a link that has been observed in young and old individuals who are healthy, although evidence is limited in patients with CFS. Objective. The purpose of this study was to examine whether recovery of upper limb muscle function could be a significant predictor of cognitive performance in patients with CFS and in patients with CFS and comorbid fibromyalgia. Furthermore, this study determined whether cognitive performance is different between these patient groups. Design. A case-control design was used. Methods. Seventy-eight participants were included in the study: 18 patients with CFS only (CFS group), 30 patients with CFS and comorbid fibromyalgia (CFS+FM group), and 30 individuals who were healthy and inactive (control group) were studied. Participants first completed 3 performance-based cognitive tests designed to assess selective and sustained attention, cognitive inhibition, and working memory capacity. Seven days later, they performed a fatiguing upper limb exercise test, with subsequent recovery measures. Results. Recovery of upper limb muscle function was found to be a significant predictor of cognitive performance in patients with CFS. Participants in the CFS+FM group but not those in the CFS group showed significantly decreased cognitive performance compared with the control group. Limitations. The cross-sectional nature of this study does not allow for inferences of causation. Conclusions. The results suggest that better physical health status could predict better mental health in patients with CFS. Furthermore, they underline disease heterogeneity, suggesting that reducing this factor in future research is important to better understand and uncover mechanisms regarding the nature of diverse impairments in these patients. INSET: The Bottom Line. [ABSTRACT FROM AUTHOR]

The article reports on research which was conducted to investigate the subclinical effects of aerobic training in an urban environment. Researchers evaluated two groups of untrained volunteers who completed an aerobic training program in an urban or rural environment. They found that aerobic training in an urban environment with high traffic-related air pollution increased inflammatory biomarkers, and that when compared to aerobic training in a rural environment, subjects who trained in an urban environment did not see improvements in cognitive performance on the Stroop task.