Subjects
The sample was composed of 117 Caucasian healthy adult female volunteers from the area of Andalucía (Spain) (age: 42.97 ± 10.84 yrs; height: 161 ± 0.07 cms; Weight: 82.56 ± 14.46 kgs). All patients were recruited from two private clinics, to which women went to lose weight.
The sample size was calculated using Fleiss equation, for a power of 80%, a two-sided significance level of 95% and expecting that 5% of the women who do not receive exercise intervention lose weight while this figure will reach 40% in those receiving exercise prescription (moderate or high dose). Although sample resulted in 51 individuals (17 women per group: non-exercise, moderate and a high dose of exercise), a size of 60 women (20 for each group), was finally estimated, to mitigate the effect of possible losses during this trial.
All the participants reported that they did not perform any particular physical activity, so they categorized as sedentary. The initial study required adulthood who classified as overweight or obese according to the body mass index (BMI, calculated as kg / m2) of ≥ 25) and that they should not be taking a diet to lose weight at the time of the interview or have been on a diet in the 6 months prior to recruitment. People who met these criteria were invited to attend a familiarization session, lasting approximately 1 hour, on an individual basis with a dietitian-nutritionist. In this session, patients provided information about how to carry out the diet, as well as pedagogical information about the healthy lifestyle and food. At this time, a complete medical history and informed consent recorded.
Women with the following pathologies or special situations were excluded from the study: Type II diabetes, being or trying to be pregnant, being in a maternal lactation period, suffering from kidney failure, being underage, presenting healthy weight (BMI ≤ 25) or receiving anti-depression pharmacological treatment. On the other hand, the inclusion criteria were: having a body fat percentage ≥ 30, being sedentary, and not having been submitted to a restrictive diet in the six months before the beginning of the study. The flow chart of the participants is shown in Fig. 1. Those women who met the eligibility criteria were scheduled for initial body measurements.
This study was approved by the bioethical committee of Córdoba University, in the Department of Health at the Regional Government of Andalusia (Act nº284, ref.4156).
Subject randomization
After obtaining the written informed consent, and completing initial screening tests, subjects were assigned to one of three groups: control, moderate physical activity, and intense physical activity group, through standard computer-based procedures (random number generator). After completing the tests, subjects were randomly assigned to 1 of 3 experimental groups: a control group that only follows a hypocaloric diet without prescription of physical activity (CON) (n = 29) or a moderate training group (MPA) that in addition to supporting the same diet, is assigned to perform moderate physical activity (n = 25) and a group of intense physical activity (IPA) (n = 27).
Figure 1.
Testing sessions
The initial assessment was carried out in the 24–48 hours before the beginning of the intervention. From this moment, an appointment was given to each patient. The follow-up during the time of the study was carried out after the overnight fast and always on the same day and time of the week in order to minimized variability between sessions. The initial evaluation included a completed anthropometric study: height, total body weight, body fat (BF), muscle mass (MM), and body water. These parameters were all recorded in every weekly session together with the PA data.
Dietary intervention
Subjects were provided with customized dietary plans designed by an experienced nutritionist (A.H.R). The daily energy requirements were determined by estimating the energy expenditure as previously reported Harris-Benedict [21]:
(655.0955 + 9.5634 [Weight (kg)] + 1.8496 [Height (cm)] – 4.6756 Age (in years).
A multiplier factor of 1.5 was applied to the value resulted in the equation in those patients carrying out physical activity. [22] During a period of 24 weeks, all the patients followed a diet with the following distribution of macronutrients: 25–30% proteins, 40–45% carbohydrates, and 30–35% fat. The moderated-fat restricted-calorie Mediterranean diet is rich in vegetables and low in red meat, with poultry and fish replacing beef and lamb, with a goal of no more than 35% of calories from fat. This diet is based on the recommendations of Willett and Skerrett. [23] The diet was hypocaloric with a reduction of 500 kcal/day during the treatment period to achieve a weekly weight loss of 400 grams, an amount that is a safe, achievable, and clinically meaningful goal for weekly weight loss. [24] Dietary protein intake was set at 1.8 g/kg of body mass, as higher protein consumption has been shown to help offset losses in lean tissue mass and promote greater adherence to the nutritional regimen (REF). [25] No vitamins or other nutritional complements were prescribed. After being included in the study, each woman participated in a 1-hour seminar in which the Dietitian-Nutritionist instructed them on how to make a suitable selection of food and prepare it. The menu proposed was valid for one week, and a new diet was provided to each woman in the weekly follow up appointment. The energy and nutritional intake were evaluated by the program Dietowin® and the weighing method (Dietowin 8.0, 2015). [26] Continued nutritional guidance was provided to the subjects at the time of each training session by the research team to encourage dietary adherence.
Exercise training intervention
To estimate the degree of physical and sedentary activity at the beginning of the study, we used the extended version of the International Physical Activity Questionnaire (IPAQ-long), which is reliable and valid for estimating physical activity and sitting-down time [27]. To adjust for sedentary behavior and physical activities outside working hours, the IPAQ-long was interview-administered at the beginning of the study and repeated at the end of the intervention. For the PA, the strata proposed by Matthews were applied. [28] A pedometer was installed on the mobile phones of all patients (ACCUPEDO). Accupedo uses the phone´s built-in accelerometer in its algorithm. The application is designed to work regardless of whether the phone is placed. Each woman was carefully informed about how to wear the device during walking hours. The app recorded all the steps executed during the day without user intervention. The caloric cost of physical activity was calculated based on the one metabolic equivalent (MET) criteria, defined as the amount of oxygen consumed while sitting at rest with a value of 3.5 ml O2 per kg body weight x min. The MET concept represents a simple, practical, and qu ickly understood the procedure for expressing the energy cost of physical activities as a multiple of the resting metabolic rate. [29]
Patients were allocated in one of three different training groups.
The CG was provided with information related to daily recommended PA levels and information about the benefits of walking regularly at least 30 minutes daily; approximately 5,000 steps can be reached during this training session. This level of physical activity can be considered sedentary or o low level, that requires minimal movement or energy expenditure (1–4 metabolic equivalent units; METs) and is associated with sitting or lying down during walking hours. [30] Patients in the MPA were provided with the same information as the CG about the benefits of walking. This group was prescribed to achieve a goal-setting of 10,000 steps per day and were informed that this value was equivalent to 60 minutes of walking per day, that they had to reach a moderate-vigorous rate, around 60% of VO2max. [31] Their heart rate (HR) was calculated using the Karvonen formula, [32] and the maximum HR was determined by the formula: 220 – age (years). This level of physical activity has a rate of 5–8 units of METs. For the IPA, the patients had to training sessions of intense physical activity with an intensity between 60 and 80% of maximal muscle strength three times a week. [33] During the 24 weeks lasted the study, the participants in the IPA group were prescribed three BodyPump sessions weekly supported by free access to fitness club offering this exercise during the intervention period.
BodyPump is a pre-choreographed and strengthening workout session. Each session includes strength exercises targeting specific muscle groups, and the participants exercise with a weight bar (1.25 kg), plates (1, 2.5 or 5 kg), and a step. Each session includes between 800 and 1000 repetitions in the range of 50–100 repetitions in each muscle group. There are 1–2 min rest periods between each track, used to change weights and prepare for the next exercises. [34] Women did not walk the BodyPump days, but the rest days of the week, they had to walk 1 hour at the same intensity as the MPA group, to unify the volume dedicated to the exercise in each group. The IPA group had a substantial caloric cost of more than 8 METs.
The follow-up tests began during the first week of the diet and physical activity assignment. The body composition was measured following an overnight fast, and the subject was required to go to the center on the same day of the week, at the same time, and to wear the same clothes. Review appointments continued weekly until week 24 when all the variables were collected.
Anthropometrics and body composition measurements
Body fat percentage (%BF), MM and the percentage of water (%W), were considered as being result variables, and were monitored and recorded throughout the time by multifrequency electrical impedance (BWB-800A, Tanita Corp. USA), previously validated. [35] This method is based on a 3-compartment model capable of evaluating BF, MM and bone mineral content. Also, the percentage difference of each dependent variable collected in the control consultations were recorded and compared to that in the first consultation, to evaluate the changes produced. The independent variables recorded were: age (years), height (cm), weight (Kg) and BMI (Kg/m2).
The anthropometric measurements were taken following the recommendations of the standardized anthropometry handbook, [36] and by professionals in order to reduce the coefficient of variation. Each measurement was taken at 3 different times, calculating the mean value. All the quantitative variables were measured with a precision of 0.1. For the height, a stadiometer was used (SECA 213).
Statistical analyses
The quantitative variables have been presented with mean and standard deviation, whereas the qualitative ones in frequencies and percentages. To contrast, the goodness of fit to a normal distribution of data coming from quantitative variables, the Kolmogorov-Smirnov test corrected by Lilliefors, was employed. To compare the bivariate hypothesis, the 2-means Student's t-test was applied, while for the qualitative variables, the Chi-square test was used, and the Fisher exact one when necessary. Likewise, for the analysis of three or more means, the ANOVA repeated means test was employed to evaluate the effects of the intervention at the baseline moment, and 3 and 6 months, and the correlation between the quantitative variables was checked by the Pearson (r) coefficient of correlation. Finally, in the case of not meeting the normality or homoscedasticity criterion, the non-parametric versions of the above tests were made.
Adjusted linear regressions were made for each variable of the body composition (%BF and MM) and the weight at the end of the study to estimate the Beta standardized coefficients of the physical activity in achieving the goals. To determine the goodness of fit of the models, the standard error, the adjusted coefficient of determination, the F statistics, the analysis of the linearity, and the residues were analyzed.
For all the statistical analyses, an alpha error probability of under 5% (p < 0.05) was accepted, and the interval of confidence was calculated as being 95%. For the statistical analysis, the computer programs IBM SPSS Statistics version 22.0 were used.
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