Modelos matemáticos para estimativa do consumo máximo de oxigênio pela ventilometria de esforço em indivíduos saudáveis

The relation between metabolic demand and maximal oxygen consumption during exercise have been investigated in different areas of knowledge. In the health field, the determination of maximal oxygen consumption (VO2max) is considered a method to classify the level of physical fitness or the risk of cardiocirculatory diseases. The accuracy to obtain data provides a better evaluation of functional responses and allows a reduction in the error margin at the moment of risk classification, as well as, at the moment of determination of aerobic exercise work load. In Brasil, the use of respirometry associated to ergometric test became an opition in the cardiorespiratory evaluation. This equipment allows predictions concerning the oxyredutase process, making it possible to identify physiological responses to physical effort as the respiratory threshold. This thesis focused in the development of mathematical models developed by multiple regression validated by the stepwise method, aiming to predict the VO2max based on respiratory responses to physical effort. The sample was composed of a ramdom sample of 181 healthy individuals, men and women, that were randomized to two groups: regression group and cross validation group (GV). The voluntiars were submitted to a incremental treadmill test; objetiving to determinate of the second respiratory threshold (LVII) and the Peak VO2max. Using the método forward addition method 11 models of VO2max prediction in trendmill were developded. No significative differences were found between the VO2max meansured and the predicted by models when they were compared using ANOVA One-Way and the Post Hoc test of Turkey. We concluded that the developed mathematical models allow a prediction of the VO2max of healthy young individuals based on the LVII

Relação entre o ciclo sono e vigília e a função cardiorrespiratória em estudantes de medicina

Students, normally, present an irregular sleep pattern characterized by delays in sleep onset and offset from weekdays to weekends, short sleep duration on weekdays and long sleep duration on weekends. The reduction of the necessary sleep and the irregularity in the sleep patterns provoke relevant short- and long-term impairments on performances, for example, in cardiorespiratory function. The cardiorespiratory performance represents, in addition to fitness, traces associated to health conditions and in several studies to pattern and/or individual s sleep quality. The aim of this study was to evaluate the pattern of the sleep-wake cycle and the cardiorespiratory function of medical students under different class schedules. The study was accomplished with two classes of medical students of UFRN, one had classes at 7 am (n = 47) and the second had classes at 8 am (n = 41) during the week. On the first stage of the study all volunteers filled out an anamnesis, the International Physical Activity questionnaire, the Pittsburgh index of sleep quality, the Portuguese version of the Horne and Östberg cronotype questionnaire, the Health and Sleep questionnaire and the Epworth Scale of Somnolence (ESS). On the second stage, 24 students (12 of each class) had their activity rhythm monitored by actimeters set to record activity at a 2-min interval for 14 days concomitant to the completion of the sleep diary. In this same stage, each volunteer performed the effort test (treadmill) only once in the morning period (between 9:00 and 11:00). The students showed an irregular pattern of the sleep-wake cycle and this irregularity is strongly influenced by the class schedules, in addition to the contribution of the academic demand, social activities and endogenous factors. The students who woke up earlier showed greater irregularity in the sleep-wake pattern. The earlier was the class schedule the worse was the sleep quality and the greater was the frequency of students with excessive diurnal somnolence. The classes schedules and the irregular pattern of the sleep-wake cycle did not show effect on the cardiorespiratory performance of the medical students. The performance on the test seems to be affected by other factors, which can be related to the pattern of the sleep-wake cycle or not. Therefore, it is suggested that the late start of classes provokes less irregularity on the pattern of the sleep-wake cycle. However, it was observed that this irregularity and the class schedule seem not to affect the cardiorespiratory performance directly