The effects of high intensity exercise on learning and memory impairments followed by combination of sleep deprivation and demyelination induced by etidium bromide

Abstract

Introduction: Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system. Cognitive impairments occurs in MS patients including learning and memory impairments. More than 50% of MS patients suffer from sleep problems. It has been suggested that in animal models exercise has direct neuroprotective effects on MS and sleep deprivation (SD). In this research, MS impairments were induced using a demyelination model as an indicator of MS disease. Also induction of SD was done using multiple platform. In order to focus on the research question, combination of MS model with SD was studied. In this study, the impact of treadmill exercise on learning and memory impairments was investigated.

Material and methods: Male wistar rats were used in the present study. Exercise groups exercised daily for 1?h/day for 10 consecutive days with treadmill (speed: 18?m/min and inclination: 25°). The multiple platform method was applied for the induction of a 72?h SD. The cognitive functions were evaluated using Morris water maze (MWM) and open field tests. Animals were anaesthetized with a certain dose of ketamine and xylazin. After full anesthesia, the rat was placed on rat stereotaxic instrument in the skull-flat position. Demyelination was induced bilaterally by direct single injection of 3?µl of 0.01% ethidium bromide in sterile 0.9% saline at the rate of 1?µl/min into the hippocampal formation. The dose was injected using appropriate stereotaxic coordinates.

Results: All of the learning and memory indices in the MWM task showed that SD and hippocampal demyelination destroy learning and memory. It seems that exercise can modulate the destructive effects of SD and demyelination on learning and memory at the behavioral level.     

Heart rate recovery after constant‐load exercise tests is decreased in proportion to the importance (severity and diffusion) of exercise‐induced lower‐limb ischaemia

Background: Conditions that may influence heart rate recovery at 1 min of recovery from exercise (HRR1: end‐exercise heart rate minus heart rate 1 min after exercise) are not fully understood. We hypothesized that the ‘importance’ (both local severity and regional diffusion) of peripheral skeletal muscle ischaemia is associated with low HRR1. Design and Methods: In 529 patients with suspected or confirmed peripheral vascular disease not receiving beta‐blockers (61·4 ± 11·3 years old), we retrospectively studied the relationship of HRR1 to exercise‐induced changes in transcutaneous oxygen DROP index (limb changes minus chest changes from rest). The sum of DROP indices observed on both calves and both buttocks (DROPtot) provides the unique opportunity to estimate both the severity and the diffusion of exercise‐induced ischaemia on the right and left side simultaneously. It was used during a constant‐load treadmill test (3·2 km h^?1; 10% grade) to classify patients in quartiles, the fourth quartile representing the more ‘important’ ischaemias. Results: There was an inverse relationship between quartiles of DROPtot and HRR1, even after adjustment for heart rate reserve (Delta HR: end‐exercise minus resting heart rate), age (≤ or >60 years), gender, body mass index, treadmill maximal walking distance and ankle brachial index: adjusted R = 0·629; P<0·0001. Conclusions: During constant‐load treadmill testing, DROPtot, an index of the ‘importance’ of exercise‐induced lower‐limb ischaemia, correlates with HRR1. Whether HRR1 is improved in proportion of DROPtot improvement in patients undergoing surgery or rehabilitation for peripheral artery disease is a fascinating issue for future studies.     

Effects of phototherapy plus physical training on metabolic profile and quality of life in postmenopausal women

A cluster of metabolic abnormalities are markedly higher among postmenopausal women. The present study evaluated the effects of infrared light emitting diode (LED) during treadmill training on multiple metabolic markers, body fat, dietary habits and quality of life in postmenopausal women. Forty-five postmenopausal women aged 50–60 years were randomly assigned to one of three groups, and of these, 30 women successfully completed the full study. The three groups were as follows: (i) the LED group, which performed treadmill training associated with phototherapy (n = 10); (ii) the exercise group, which carried out treadmill training only (n = 10); and (iii) the sedentary group, which neither performed physical training nor underwent phototherapy (n = 10). Training was performed over a period of six months, twice a week for 45 min per session at 85–90% of maximal heart rate (HR_max), which was obtained during a progressive exercise testing. The average HR and velocity during treadmill training were 144 ± 9 bpm and 5.8 ± 1.3 km/h for both trained groups. The irradiation parameters were 100 mW, 39 mW/cm² and 108 J/cm² for 45 min. Anthropometric data, skinfolds thickness, biochemical exams (lipid profile, glucose and insulin levels), dietary habits and quality of life were evaluated. The sum of skinfolds significantly improved in the exercise and sedentary groups (p < 0.05). Additionally, there was an improvement in lipid profile, particularly, total cholesterol and low-density lipoprotein, which reduced significantly for all groups (p ? 0.05). However, intake of saturated fats was significantly reduced in the sedentary group only (p < 0.05). The quality of life improved in the LED group only, with a significant reduction in the total WHQ score (p < 0.05). Physical training with or without phototherapy may improve the metabolic profile. In addition, phototherapy together with treadmill training prevented an increase in subcutaneous fat and facilitated an improved quality of life in postmenopausal women.     

Influence of Prolonged Running and Training on Tibial Acceleration and Movement Quality in Novice Runners

ContextChanges in lower limb loading and movement quality after prolonged running and training periods might influence injury risks in runners.ObjectivesTo assess (1) the effects of a single prolonged run and a 3-week running training program on peak tibial acceleration (PTA) during running and Functional Movement Screen (FMS) criterion tests, and (2) the relationship between running volume during the 3-week training program and changes in PTA and FMS scores after training.DesignCase series.SettingResearch laboratory.Patients or Other ParticipantsTen novice runners (age = 27 ± 7 years) with 15 ± 14 months of running experience, who ran on average 19.6 ± 4.8 km per week at a preferred pace of 7:05 ± 1:30 minutes per km.Main Outcome Measure(s)Participants completed a 30-minute submaximal prolonged treadmill run and 3-week training program with 25% increases in weekly running volume. Peak tibial acceleration and the deep-squat and active straight-leg–raise criterion FMS test scores were assessed before and after the prolonged run at enrollment and after the training program (ie, 3 testing sessions).ResultsNo differences in PTA or FMS scores were observed among the 3 testing times. Although the changes in PTA (r = 0.57) and FMS aggregate score (r = 0.15) were not significantly correlated with training volume, training volume explained 32% of the variance in the PTA change from before to after training.ConclusionsOur findings suggest that tibial acceleration and movement quality were not influenced by a single submaximal-effort prolonged run or a 3-week training period. However, novice runners who have a greater increase in running volume might be more susceptible to training-related changes in tibial acceleration than those whose running volume is less.