M.T. de Mello

SPATIAL MEMORY IS IMPROVED BY AEROBIC AND RESISTANCE EXERCISE THROUGH DIVERGENT MOLECULAR MECHANISMS

A growing body of scientific evidence indicates that exercise has a positive impact on human health, including neurological health. Aerobic exercise, which is supposed to enhance cardiovascular functions and metabolism, also induces neurotrophic factors that affect hippocampal neurons, thereby improving spatial learning and memory. Alternatively, little is known about the effect of resistance exercise on hippocampus-dependent memory, although this type of exercise is increasingly recommended to improve muscle strength and bone density and to prevent age-related disabilities. Therefore, we evaluated the effects of resistance training on spatial memory and the signaling pathways of brain-derived neurotrophic factor (BDNF) and insulin-like growth factor 1 (IGF-1), comparing these effects with those of aerobic exercise. Adult male Wistar rats underwent 8 weeks of aerobic training on a treadmill (AERO group) or resistance training on a vertical ladder (RES group). Control and sham groups were also included. After the training period, both AERO and RES groups showed improved learning and spatial memory in a similar manner. However, both groups presented distinct signaling pathways. Although the AERO group showed increased level of IGF-1, BDNF, TrkB, and β-CaMKII (calcium/calmodulin-dependent kinase II) in the hippocampus, the RES group showed an induction of peripheral and hippocampal IGF-1 with concomitant activation of receptor for IGF-1 (IGF-1R) and AKT in the hippocampus. These distinct pathways culminated in an increase of synapsin 1 and synaptophysin expression in both groups. These findings demonstrated that both aerobic and resistance exercise can employ divergent molecular mechanisms but achieve similar results on learning and spatial memory.

Incidence of periodic leg movements and of the restless legs syndrome during sleep following acute physical activity in spinal cord injury subjects.

The purpose of the present study was to evaluate sleep patterns and complaints, and Periodic Limb Movement (PLM) and the Restless Legs Syndrome (RLS) in subjects with complete spinal cord injury. Volunteers were submitted to two polysomnograms (Oxford Medilog SAC system - EEG, EMG, EOC): (1) basal night, when the volunteer arrived at the Sleep Center, and (2) after a maximal physical test (Cybex Met 300/increase of 12,5 watts/2 min until exhaustion). Eleven volunteers with complete spinal cord injury between T7-T12 were evaluated. Data were analyzed by the paired Students t test (total sleeping time) and by the Wilcoxon matched paired test (change of sleep stages, number of awakenings during sleep, latency to REM sleep and leg movements - PLM + RLS). Comparison of sleep recordings from the night before with that from the night after (12 h) practice of physical activity, showed a significant reduction in all of the sleep parameters. The results indicate that physical activity improves the sleep patterns of spinal cord injured volunteers. In particular, we noticed that PLM and RLS after physical activity were inhibited during sleep.

Sleep and muscle recovery: Endocrinological and molecular basis for a new and promising hypothesis

Sleep is essential for the cellular, organic and systemic functions of an organism, with its absence being potentially harmful to health and changing feeding behavior, glucose regulation, blood pressure, cognitive processes and some hormonal axes. Among the hormonal changes, there is an increase in cortisol (humans) and corticosterone (rats) secretion, and a reduction in testosterone and Insulin-like Growth Factor 1, favoring the establishment of a highly proteolytic environment. Consequently, we hypothesized that sleep debt decreases the activity of protein synthesis pathways and increases the activity of degradation pathways, favoring the loss of muscle mass and thus hindering muscle recovery after damage induced by exercise, injuries and certain conditions associated with muscle atrophy, such as sarcopenia and cachexia.

Association between body mass index and sleep duration assessed by objective methods in a representative sample of the adult population

INTRODUCTION Sleep duration has been associated with overweight individuals in many epidemiological studies; however, few studies have assessed sleep using objective methods. Our study was designed to evaluate the association between body mass index (BMI) and sleep duration measured by actigraphy (Acti), polysomnography (PSG) and the Pittsburgh sleep quality index questionnaire (PSQIO). Furthermore, we evaluated other biochemical and polysomnographic parameters. METHODS A representative sample of 1042 individuals from Sao Paulo, Brazil, including both genders (20-80 yrs), participated in our protocol. Weight and other anthropometric parameters were measured at the onset of the study. Sleep duration was calculated by Acti, PSG, and the PSQIQ. The population was sorted by sleep duration, body, slow wave sleep (SWS) and REM sleep (REMS) duration subsets. In addition, other biochemical and polysomnographic parameters were analyzed. Differences between population subsets were analyzed by one-way analysis of variance (ANOVA). Linear regression analysis was performed between sleep and anthropometric parameters. RESULTS Shorter sleep duration was associated with higher BMI and waist and neck circumference when measured by Acti and PSG (p<0.05). Lower leptin levels were associated with short sleep in normal-weight (BMI>18 and ⩽25) individuals (p<0.01). The association between short sleep duration Acti and higher BMI was present when apnea-hypopnea index (AHI) was less than 15 (p=0.049). Shorter REMS and SWS also were associated with higher BMI (p<0.01). Normal-weight individuals tended to sleep longer, have higher sleep efficiency and longer SWS and REMS than obese individuals (Acti, PSG; p=0.05). Sleep duration was negatively correlated with BMI (Acti, PSG; p<0.05). Short SWS and REMS were associated with higher cardiovascular risk factors (p<0.05). CONCLUSION Shorter sleep, SWS, and REMS duration were associated with higher BMI, central adiposity measurements, and cardiovascular risk factors when measured by objective methods.

Comparison between dopaminergic agents and physical exercise as treatment for periodic limb movements in patients with spinal cord injury

Study design: Randomized controlled trial of physical exercise and dopaminergic agonist in persons with spinal cord injury and periodic leg movement (PLM).Objective: The objective of the present study was to compare the effectiveness of physical exercise and of a dopaminergic agonist in reducing the frequency of PLM.Setting: Centro de Estudos em Psicobiologia e Exercício. Universidade Federal de São Paulo, Brazil.Methods: A total of 13 volunteers (mean age: 31.6±8.3 years) received L-DOPA (200 mg) and benserazide (50 mg) 1 h before sleeping time for 30 days and were then submitted to a physical exercise program on a manual bicycle ergometer for 45 days (3 times a week).Results: Both L-DOPA administration (35.11–19.87 PLM/h, P<0.03) and physical exercise (35.11–18.53 PLM/h, P<0.012) significantly reduced PLM; however, no significant difference was observed between the two types of treatment.Conclusions: The two types of treatment were found to be effective in the reduction of PLM; however, physical exercise is indicated as the first treatment approach, while dopaminergic agonists or other drugs should only be recommended for patients who do not respond to this type of treatment.

Moderate exercise training modulates cytokine profile and sleep in elderly people

Aging causes several physiological alterations, including alterations in sleep. It is possible that difficulty sleeping can be exacerbated by increased inflammation in older individuals. Moderate exercise training may be a modality of non-pharmacological treatment for sleep disorders and inflammation. We aimed to assess the effects of moderate exercise training on sleep in elderly people as well as their cytokine profiles. Additionally, we examined the effect of exercise training on quality of life parameters using a SF-36 questionnaire. Twenty-two male, sedentary, healthy, elderly volunteers performed moderate training for 60 min/day, 3 days/week for 24 week at a work rate equivalent to their ventilatory aerobic threshold. The environment was kept at a temperature of 23 ± 2°C, with a humidity of 60 ± 5%. Blood and polysomnograph were collected twice: at baseline (1 week before training began) and after 6 months of training. Training increased aerobic capacity parameters (p<0.0001), decreased REM latency (p<0.02), and decreased time awake (p<0.05). After training, the levels of IL-6 (p<0.0001) and TNF-α (p<0.0001) and the ratio of TNF-α/IL-10 (p<0.0001) were decreased, whereas IL-10 levels were increased after training (p<0.001). Furthermore, exercise training was shown to improve quality of life parameters. Our results suggest that 6 months of training can improve sleep in the elderly and is related to the anti-inflammatory effect of moderate training, which modifies cytokine profiles.

Gender and age differences in polysomnography findings and sleep complaints of patients referred to a sleep laboratory

Our objective was to examine the effet of gender on the sleep pattern of patients referred to a sleep laboratory. The data (questionnaires and polysomnographic recordings) were collected from a total of 2365 patients (1550 men and 815 women). The polysomnography permits an objective assessment of the sleep pattern. We included only polysomnography exams obtained with no more than one recording system in order to permit normalization of the data. Men had a significantly higher body mass index than women (28.5 +/- 4.8 vs 27.7 +/- 6.35 kg/m(2)) and had a significantly higher score on the Epworth Sleepiness Scale (10.8 +/- 5.3 vs 9.5 +/- 6.0), suggesting daytime sleepiness. Women had a significantly higher sleep latency than men, as well as a higher rapid eye movement (REM) latency. Men spent more time in stages 1 (4.6 +/- 4.1 vs 3.9 +/- 3.8) and 2 (57.0 +/- 10.5 vs 55.2 +/- 10.1) of non-REM sleep than women, whereas women spent significantly more time in deep sleep stages (3 and 4) than men (22.6 +/- 9.0 vs 19.9 +/- 9.0). The apnea/hypopnea and arousal indexes were significantly higher and more frequent in men than in women (31.0 +/- 31.5 vs 17.3 +/- 19.7). Also, periodic leg movement index did not differ significantly between genders, but rather differed among age groups. We did not find significant differences between genders in the percentage of REM sleep and sleep efficiency. The results of the current study suggest that there are specific gender differences in sleep pattern.

Changes in the salivary biomarkers induced by an effort test.

Physical exercise induces biochemical changes in the body that modify analytes in blood and saliva among other body fluids. This study analyzed the effect of an incremental effort test on the salivary protein profile to determine whether any specific protein is altered in response to such stress. We also measured thresholds of salivary alpha amylase, total salivary protein and blood lactate and searched for correlations among them. Twelve male cyclists underwent a progressive test in which blood and saliva samples were collected simultaneously at each stage. The salivary total protein profile revealed that physical exercise primarily affects the polypeptide corresponding to salivary alpha-amylase, the concentration of which increased markedly during the test. We observed thresholds of salivary alpha-amylase (sAAT), total salivary protein (PAT) and blood lactate (BLT) in 58%, 83% and 100% of our sample, respectively. Pearsons correlation indicates a strong and significant association between sAAT and BLT (r= 0.84, P<0.05), sAAT and PAT (r= 0.83, P<0.05) and BLT and PAT (r= 0.90, P<0.05). The increased expression of the salivary alpha-amylase (sAA) polypeptide suggests that sAA is the main protein responsible for the increase in total protein concentration of whole saliva. Therefore, monitoring total protein concentration is an efficient tool and an alternative noninvasive biochemical method for determining exercise intensity.

Prevalence and risk factors of metabolic syndrome in Brazilian and Italian obese adolescents: a comparison study

Background:  Metabolic syndrome (MS) prevalence between different populations in obese adolescents is scanty to date.

Reduction of periodic leg movement in individuals with paraplegia following aerobic physical exercise.

Purpose: According to the American Association of Sleep Disorders, periodic leg movements (PLM) are classified into the group of intrinsic sleep disorders. Studies on PLM in individuals with spinal cord injury are very recent. The objective of the present study was to assess the efficacy of aerobic training in reducing the index/score of PLM in individuals with complete spinal cord injury.Methods: Twelve male volunteers with complete spinal cord injury between T7 and T12 were submitted to six polysonographies (PSG Oxford Medilog SAC system; EEG, EMG and EOG: (1) basal night, (2) 12 h after a maximum effort test, (3) 36 h after a maximum effort test, (4) after 44 days of aerobic physical training, (5) 12 h after the last training session, and (6) 36 h after the last training session. All volunteers participated in a physical training program for 44 days using an arm crank ergometer. Data were analyzed statistically by the Wilcoxon test, with the level of significance set at α5%.Results: The results demonstrated a statistically significant reduction (P⩽0.05) in the comparison of first evaluation (35.1 PLM/h) with fifth (12.70 PLM/h) and sixth evaluation (18.5 PLM/h).Conclusion: This study suggests that a program of regular and systematized physical activity promotes an effective reduction of PLM in individuals with spinal cord injury.