Executive function after exhaustive exercise

PurposeFindings concerning the effects of exhaustive exercise on cognitive function are somewhat equivocal. The purpose of this study was to identify physiological factors that determine executive function after exhaustive exercise.MethodsThirty-two participants completed the cognitive tasks before and after an incremental exercise until exhaustion (exercise group: N = 18) or resting period (control group N = 14). The cognitive task was a combination of a Spatial Delayed-Response (Spatial DR) task and a Go/No-Go task, which requires executive function. Cerebral oxygenation and skin blood flow were monitored during the cognitive task over the prefrontal cortex. Venous blood samples were collected before and after the exercise or resting period, and blood catecholamines, serum brain-derived neurotrophic factor, insulin-like growth hormone factor 1, and blood lactate concentrations were analyzed.ResultsIn the exercise group, exhaustive exercise did not alter reaction time (RT) in the Go/No-Go task (pre: 861 ± 299 ms vs. post: 775 ± 168 ms) and the number of error trials in the Go/No-Go task (pre: 0.9 ± 0.7 vs. post: 1.8 ± 1.8) and the Spatial DR task (pre: 0.3 ± 0.5 vs. post: 0.8 ± 1.2). However, ΔRT was negatively correlated with Δcerebral oxygenation (r = −0.64, P = 0.004). Other physiological parameters were not correlated with cognitive performance. Venous blood samples were not directly associated with cognitive function after exhaustive exercise.ConclusionThe present results suggest that recovery of regional cerebral oxygenation affects executive function after exhaustive exercise

Slowed response to peripheral visual stimuli during strenuous exercise

Recently, we proposed that strenuous exercise impairs peripheral visual perception because visual responses to peripheral visual stimuli were slowed during strenuous exercise. However, this proposal was challenged because strenuous exercise is also likely to affect the brain network underlying motor responses. The purpose of the current study was to resolve this issue. Fourteen participants performed a visual reaction-time (RT) task at rest and while exercising at 50% (moderate) and 75% (strenuous) peak oxygen uptake. Visual stimuli were randomly presented at different distances from fixation in two task conditions: the Central condition (2° or 5° from fixation) and the Peripheral condition (30° or 50° from fixation). We defined premotor time as the time between stimulus onset and the motor response, as determined using electromyographic recordings. In the Central condition, premotor time did not change during moderate (167 ± 19 ms) and strenuous (168 ± 24 ms) exercise from that at rest (164 ± 17 ms). In the Peripheral condition, premotor time significantly increased during moderate (181 ± 18 ms, P < 0.05) and strenuous exercise (189 ± 23 ms, P < 0.001) from that at rest (173 ± 17 ms). These results suggest that increases in Premotor Time to the peripheral visual stimuli did not result from an impaired motor-response network, but rather from impaired peripheral visual perception. We conclude that slowed response to peripheral visual stimuli during strenuous exercise primarily results from impaired visual perception of the periphery

Cognitive function during exercise under severe hypoxia

Acute exercise has been demonstrated to improve cognitive function. In contrast, severe hypoxia can impair cognitive function. Hence, cognitive function during exercise under severe hypoxia may be determined by the balance between the beneficial effects of exercise and the detrimental effects of severe hypoxia. However, the physiological factors that determine cognitive function during exercise under hypoxia remain unclear. Here, we examined the combined effects of acute exercise and severe hypoxia on cognitive function and identified physiological factors that determine cognitive function during exercise under severe hypoxia. The participants completed cognitive tasks at rest and during moderate exercise under either normoxic or severe hypoxic conditions. Peripheral oxygen saturation, cerebral oxygenation, and middle cerebral artery velocity were continuously monitored. Cerebral oxygen delivery was calculated as the product of estimated arterial oxygen content and cerebral blood flow. On average, cognitive performance improved during exercise under both normoxia and hypoxia, without sacrificing accuracy. However, under hypoxia, cognitive improvements were attenuated for individuals exhibiting a greater decrease in peripheral oxygen saturation. Cognitive performance was not associated with other physiological parameters. Taken together, the present results suggest that arterial desaturation attenuates cognitive improvements during exercise under hypoxia

Acute bout of exercise downregulates thioredoxin-interacting protein expression in rat contracting skeletal muscles

We previously reported that in rat skeletal muscle, disuse (i.e., decreased muscle contractile activity) rapidly increases thioredoxin-interacting protein (TXNIP), which is implicated in the reduced glucose uptake. Accordingly, we sought herein to (a) determine the effect of exercise (i.e., increased muscle contractile activity) on muscle TXNIP protein expression, and (b) elucidate the mechanisms underlying the changes of TXNIP protein expression in response to exercise. Rat epitrochlearis and soleus muscles were dissected out after an acute bout of 3-hr swimming (without weight loading) or 3-hr treadmill running (15% grade at 9m/min). In a separate protocol, the isolated epitrochlearis and soleus muscles were incubated for 3 hr with AMP-dependent protein kinase activator AICAR. Immediately after the cessation of the 3-hr swimming, the TXNIP protein was decreased in epitrochlearis but not in soleus muscle. Conversely, 3-hr treadmill running decreased the TXNIP protein in soleus but not in epitrochlearis muscle. TXNIP protein was decreased concomitantly with reduced postexercise muscle glycogen, showing that a decrease in TXNIP protein expression occurs in muscles that are recruited during exercise. In addition, 3-hr incubation with AICAR decreased TXNIP protein in both isolated epitrochlearis and soleus muscles. Our results suggest that (a) an acute bout of exercise downregulates TXNIP protein expression in rat contracting skeletal muscles, and (b) the reduction in TXNIP protein expression in contracting muscles is probably mediated by AMPK activation, at least in part

Effect of the interaction between physical activity and estimated macronutrient intake on HbA1c : population-based cross-sectional and longitudinal studies

Introduction Healthy diet and physical activity (PA) are essential for preventing type 2 diabetes, particularly, a combination of diet and PA. However, reports on interaction between PA and diet, especially from large epidemiological studies, are limited. We investigated the effect of interaction between PA and macronutrient intake on hemoglobin A1c (HbA1c) levels in the general population. Research design and methods We conducted a cross-sectional study of 55 469 men and women without diabetes who participated in the baseline survey of the Japan Multi-Institutional Collaborative Cohort Study. A self-administered questionnaire ascertained PA and macronutrient intake (carbohydrate, fat, and protein). Multiple linear regression analyses were performed to adjust for confounding variables and examine the interactions. In addition, we conducted a longitudinal study during a 5-year period within a subcohort (n=6881) with accelerometer-assessed PA data. Results Overall, PA had a weak inverse association (β=−0.00033, p=0.049) and carbohydrate intake had a strong positive association (β=0.00393, p<0.001) with HbA1c. We observed a tendency of interactions between PA and carbohydrate or fat intake, but not protein intake, on HbA1c levels after adjusting for age, sex, study area, total energy intake, alcohol consumption, smoking, and medication for hypertension or hypercholesterolemia (Pinteraction=0.054, 0.006, and 0.156, respectively). The inverse associations between PA and HbA1c level were more evident in participants with high-carbohydrate (or low-fat) intake than in participants with low-carbohydrate (or high-fat) intake. Although further adjustment for body mass index slightly attenuated the above interactions (Pinteraction=0.098 for carbohydrate and 0.068 for fat), the associations between PA and HbA1c level in stratified analyses remained unchanged. Similar associations and interactions were reproduced in the longitudinal study. Conclusions The present results suggest that the effect of PA on HbA1c levels is modified by intake of macronutrient composition

クマモト ジシン 6カゲツ ニ オケル シュウロウシャ ノ スイミン ト シュカンテキ ケンコウ ジョウタイ ト ノ カンレン ヨウイン

Objective：This study aimed to clarify the relationship between sleep and subjective health condition by focusing on disaster-affected workers six months after the Kumamoto earthquake.Methods：The study population comprised 676 workers at small and medium-sized companies located in Kamimashikigun, Kumamoto Prefecture, where damage after the Kumamoto earthquake was severe. Participants were sent a questionnaire with items related to basic characteristics （sex, age, and family members）, damage to home after the earthquake, subjective symptoms after the earthquake, injury from the earthquakes, changes in income, subjective wellbeing, changes in workload after the earthquake, Athens Insomnia Scale（AIS）, Impact of Event Scale-Revised（IES-R）, General Health Questionnaire（GHQ 28）, and health related QOL Short-Form Health Survey（SF-8）. Responses were collected from 456 people at 13 companies（68.1% response rate）. Of these, 438 responses（96.1%） were valid. This study was approved by the ethical review committee of Fukuoka University School of Medicine.Results：The participants included 334 males and 104 females with an average age of 43.3 years. Two groups were created based on Abbreviated Injury Scale（AIS）scores：279 participants were in the insomnia group and 159 participants were in the non-insomnia group. Compared with that in the non-insomnia group, the patients in the insomnia group were old, had poor subjective health status, and were more likely to have subjective symptoms and injury after the earthquake. The study found a significant positive correlation with intrusion and hyperarousal symptoms in the IES-R subscales. In the SF-8 responses, there were significant negative correlations with BP（Bodily Pain）, GH（General Health）, VT（Vitality）, SF（Social Functioning）, RE（Role Emotional）, MH（Mental Health）, and MCS（Mental Component Summary）. In a logistic regression analysis of sleeping condition in Athens Insomnia Scale（AIS）, BP［OR： 0.942, CI： 0.907-0.978］and avoidance symptoms［OR：0.881, CI：0.799-0.971］improved sleeping condition, whereas hyperarousal symptoms［OR：1.553, CI：1.324-1.823］, social life function［OR：0.954, CI：0.916-0.994］, and daily role function（mental）［OR：0.916, CI：0.866-0.97］were negatively related with good sleeping condition.Discussion：The Kumamoto earthquake influenced the sleep quality for most disaster-affected workers, with approximately 60% reporting insomnia. Because workers with insomnia may exhibit hidden subjective symptoms or suffer from mental stress, long-term preventive systems should be developed and established by companies to improve worker health. Longitudinal studies are required to further examine factors related to sleep condition and outcomes of support systems.原著論文 = Original articl