The Effect of Different Volumes of Physical Exercise on the Immune System

Overview

The investigators will do an intervention on four groups of previously sedentary post-menopausal women which consists: group 1 - 30 minutes per day of physical protocol; group 2 - 50 minutes per day of physical protocol; group 3 - 70 minutes per day of physical protocol; group 4 - sedentary control women. The protocol consists of three sessions per week of concurrent training (half session with aerobic training and the other part with weight training). Inflammatory and oxidative parameters will be analyzed and the investigators hypothesized that 90 minutes per week of concurrent training (group 1) will reduce the inflammatory parameters and the oxidative stress, and this improvements will be greater so much as the longer the sessions (a dose-response effect). The physical activity practiced out of the intervention will be controlled by a questionnaire (the commuting and leisure sections of the International Physical Activity Questionnaire) and the food intake by a 24-hour food recall.

The protocol will consist of an intervention based on concurrent training, for previously sedentary post-menopausal women divided on four groups: 1) control group; 2) 90 minutes of physical training per week; 3) 150 minutes of training per week; 4) 210 minutes of training per week. The control group will be oriented to maintain their normal activity and habits and will not receive the intervention. The group of 90 minutes per week will do three sessions of 30 minutes per week of concurrent training, which consists on 15 minutes of aerobic exercise and 15 minutes of strength training. The group of 150 minutes will do three sessions of 50 minutes per week, which consists on 25 minutes of aerobic exercise and 25 minutes of strength training. The group pf 210 minutes per week will do three sessions of 70 minutes per week, which consists on 35 minutes of aerobic exercise and 35 minutes of strength training. The aerobic exercise will be performed on cycle-ergometers and the subjects will exercise between the levels 14 and 15 of Borg's scale of perceived exertion. The strength training will be performed on weight machines by a linear periodization, which will consist on a week of adaptation (series of 10 to 12 submaximal repetitions), next three weeks with series of 12 to 14 maximal repetitions, weeks five to eight with series of 10 to 12 maximal repetitions, weeks nine to twelve with series of eight to 10 maximal repetitions. Al participants will do the maximum number of series of strength training that the time permits. The blood samples will be collected at the beginning of the study (week zero), at the middle (week six) and at the end (week 12). The subjects will fill a 24-hour food recall (to control the food intake) and the commuting and leisure sections of the International Physical Activity Questionnaire (to control the physical activity practiced out of the intervention).