Effects of pre-exercise carbohydrate consumption on metabolism during exercise

It is well documented that consuming carbohydrates (CHO) prior to exercise has been shown to alter metabolism. There are many ways that CHO ingestion affects substrate utilization and blood glucose dynamics at the start of exercise. Changes in the concentrations of blood glucose, insulin, glucagon, free fatty acids (FFAs) as well as varying utilizations of different substrates have been observed. Each of these responses is reflective of the body’s capacity to maintain homeostasis through different physiological conditions and demands. PURPOSE: The aim is to deduce how varying amounts (approximately 0, 12.5, 25 and 50g for a 70 kg person) of pre-exercise sucrose ingestion effects metabolism including blood glucose concentration and fat oxidation during 30 minutes of moderate intense exercise. METHODS: This will be a randomized crossover study. After the initial assessment of baseline data (VO2peak), participants will be asked to perform four cycling trials at 50% of VO2peak for 30 minutes. Forty-five minutes before each exercise trial, participants will consume 0, 12.5, 25 and 50g (for a 70kg person) of sucrose. VO2 and VCO2 will be collected for 15 minutes prior to exercise and for the entire 30 minutes of cycling. Blood glucose will be obtained through the finger prick method and collected directly prior to exercise, 5, 15 and 30 minutes into cycling. Heart rate and rate of perceived exertion will be measured every 5 minutes of exercise. DISCUSSION: It is speculated that a small dose (12.5g for a 70kg person) of pre-exercise sucrose consumption will be able to demonstrate a decline in blood glucose concentration during exercise with a step-wise reduction in fat oxidation. This dose response curve will display the sensitivity of metabolism to ingested sucrose.Kinesiology and Health Educatio

USSR Space Life Sciences Digest, issue 30

This is the thirtieth issue of NASA's Space Life Sciences Digest. It contains abstracts of 47 journal papers or book chapters published in Russian and of three Soviet monographs. Selected abstracts are illustrated with figures and tables from the original. The abstracts in this issue have been identified as relevant to 20 areas of space biology and medicine. These areas include: adaptation, biospheric research, cardiovascular and respiratory systems, endocrinology, equipment and instrumentation, gastrointestinal system, group dynamics, habitability and environmental effects, hematology, human performance, immunology, life support systems, mathematical modeling, metabolism, musculoskeletal system, neurophysiology, nutrition, psychology, radiobiology, and space biology and medicine

Ethane-beta-Sultam Modifies the Activation of the Innate Immune System Induced by Intermittent Ethanol Administration in Female Adolescent Rats

Intermittent ethanol abuse or ‘binge drinking’ during adolescence induces neuronal damage, which may be associated with cognitive dysfunction. To investigate the neurochemical processes involved, rats were administered either 1 g/kg or 2 g/kg ethanol in a ‘binge drinking’ regime. After only 3 weeks, significant activation of phagocytic cells in the peripheral (alveolar macrophages) and the hippocampal brain region (microglia cells) was present,as exemplified by increases in the release of pro-inflammatory cytokines in the macrophages and of iNOS in the microglia. This was associated with neuronal loss in the hippocampus CA1 region. Daily supplementation with a taurine prodrug, ethane-β-sultam, 0.028 g/kg, during the intermittent ethanol loading regime, supressed the release of the pro-inflammatory cytokines and of reactive nitrogen species, as well as neuronal loss, particularly in the rats administered the lower dose of ethanol, 1 g/kg. Plasma, macrophage and hippocampal taurine levels increased marginally after ethane-β-sultam supplementation. The ‘binge drinking’ ethanol rats administered 1 g/kg ethanol showed increased latencies to those of the control rats in their acquisition of spacial navigation in the Morris Water Maze, which was normalised to that of the controls values after ethane-β-sultam administration. Such results confirm that the administration of ethane-β-sultam to binge drinking rats reduces neuroinflammation in both the periphery and the brain, suppresses neuronal loss, and improved working memory of rats in a water maze study

The effects of a modest dose of alcohol on executive functioning and prospective memory

Rationale Acute alcohol intoxication selectively impairs executive functioning and prospective memory (PM). Much previous researches in this area have used laboratory-based tasks that may not mimic functions that individuals with dysexecutive syndrome have problems with in their everyday life. The present study aimed to assess the effects of a modest dose of alcohol on executive functioning and PM using a virtual reality task and investigate the role of executive planning in PM performance. Methods Forty healthy participants were administered 0.4 g/kg alcohol or matched placebo in a double-blind design. Executive function and PM were assessed using the Jansari–Agnew–Akesson–Murphy (JAAM) task, requiring participants to play the role of an office worker. Results Alcohol intoxication selectively impaired executive function and PM. The participants in the alcohol condition performed worse on the planning, prioritisation, creativity and adaptability executive subscales and also on the time-based and event-based PM tasks. However, alcohol did not impair the selection executive function task or the action-based PM task. Conclusions The results provide further support for the effects of alcohol on executive functioning and PM. In addition, the results suggest that such deficits may be present at relatively modest doses of alcohol and in the absence of a subjective feeling of intoxication Keywords: alcohol; executive functioning; prospective memory; virtual reality; memor

Pseudocontinuous arterial spin labeling reveals dissociable effects of morphine and alcohol on regional cerebral blood flow

We have examined sensitivity and specificity of pseudocontinuous arterial spin labeling (PCASL) to detect global and regional changes in cerebral blood flow (CBF) in response to two different psychoactive drugs. We tested alcohol and morphine in a placebo-controlled, double-blind randomized study in 12 healthy young men. Drugs were administered intravenously. Validated pharmacokinetic protocols achieved minimal intersubject and intrasubject variance in plasma drug concentration. Permutation-based statistical testing of a mixed effect repeated measures model revealed a widespread increase in absolute CBF because of both morphine and alcohol. Conjunction analysis revealed overlapping effects of morphine and alcohol on absolute CBF in the left anterior cingulate, right hippocampus, right insula, and left primary sensorimotor areas. Effects of morphine and alcohol on relative CBF (obtained from z-normalization of absolute CBF maps) were significantly different in the left putamen, left frontoparietal network, cerebellum, and the brainstem. Corroborating previous PET results, our findings suggest that PCASL is a promising tool for central nervous system drug research