## 3 Results  
The flow diagram with the enrolment of the study is shown in Figure 2. Thirty-one individuals were recruited, two individuals were excluded because they did not have risk of sleep apnea, three declined to participate, and seven individuals declined due to other reasons (economical problem related to the transportation). Table 1 shows some anthropometric parameters of the individuals that were exposed to WBV exercise (FV group) and to only 5 Hz (FF group). An analysis is shown of both groups before and just after the treatments. It was verified that the BMI, NC, SBP, and DBP (\(p>0.05\)) were not significantly altered in both groups. However, a significant increase in the HR (\(p<0.05\)) was found in both groups exposed to mechanical vibration, only 5 Hz (FFG) and variable frequency 5-16 Hz (VFG). Furthermore, a reduction was found in the group that was submitted to the variable frequency 5-16 Hz (VFG) in the WC. Figure 2: Flow diagram of the intervention. Figure 3 shows the values of the scores of the PSQI of the individuals of the group exposed only to mechanical vibration of 5 Hz (FFG-control). A significant decrease was found (p = 0.01) of the score (after and before) of the individuals of the FF group (exposure to 5 Hz). Figure 4 shows the values of the scores of the PSQI of the individuals of the groups exposed to the treatment with WBV exercises (VFG). It is observed that an important and significant (\(p\) = 0.008) decrease of score in the group after the exposure to various frequencies (intervention) was seen. This finding indicates an improvement of quality of the sleep. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & **FFG before** & **FFG after** & \(\mathbf{P}\) &
\begin{tabular}{c} **VFG before** \\ **(Median [IQR])** \\ \end{tabular} & \(\mathbf{P}\) \\ \hline BMI (kg/m\({}^{2}\)) & 29.50 & 29.60 & 0.54 & 35.40 & 34.70 & 0.23 \\  & [29.0, 34.20] & [28.90, 34.10] & & [32.40, 36.60] & [32.88, 36.08] & 0.23 \\ WC (cm) & 105.00 & 101.00 & 0.23 & 108.90 & 107.00 & \\  & [101.20, 106.30] & [100.00, 105.00] & & [103.75, 116.10] & [102.17, 112.85] & 0.02 \\ NC (cm) & 38.00 & 36.60 & 0.29 & 38.00 & 38.30 & 0.25 \\  & [36.40, 38.50] & [35.60, 39.50] & 0.29 & 37.58, 38.88] & [37.17, 39.00] & 0.25 \\ SBP & 129.00 & 127.00 & 0.12 & 130.00 & 130.00 & 0.76 \\ (mm Hg) & [128.00, 130.00] & [121.00, 128.00] & 0.12 & 122.50, 132.50] & [120.00, 132.00] & 0.76 \\ DBP & 78.00 & 75.00 & 0.10 & 74.00 & 70.00 & 0.18 \\ (mm Hg) & [75.00, 83.00] & [68.00, 87.00] & 0.10 & [72.25, 75.75] & [60.75, 74.75] & 0.18 \\ HR & 57.00 & 62.00 & 0.05 & 63.50 & 72.00 & 0.05 \\ (bpm) & [56.00, 62.00] & [60.00, 66.00] & 0.15 & [59.75, 66.00] & [61.25, 83.00] & 0.05 \\ \hline \hline BMI—body mass index, WC—waist circumference, NC—neck circumference, SBP—systolic blood pressure, DBP—diastolic blood pressure, HR—heart rate, FF—fixed frequency group, VF—variable frequency group. & & & & \\ \end{tabular}
\end{table} 
Table 1: Anthropometrical parameters of the individuals exposed to variable frequency group (intervention 5–16 Hz) and to only 5 Hz (fixed frequency group). Figure 3: Scores of the Pittsburgh Sleep Quality Index (PSQI) of the individuals of the group exposed only to a mechanical vibration of 5 Hz (FFG) (before and after). Figure 5 shows the values of the scores of the ESS of the individuals of the group exposed only to mechanical vibration of 5 Hz (FFG). It is observed that there was no significant decrease (\(p=1.0\)) of the score (after and before) of the individuals. This finding indicates no reduction of daytime sleepiness. Figure 6 shows the values (before and after the interventions) of the scores of the ESS scale of the individuals of the groups exposed to the treatment with WBV exercises (VFG). It is observed that there  
Figure 4: Scores of the PSQI of the individuals exposed to the whole-body vibration (WBV) intervention with variable frequency (VFG). Figure 5: Scores of the Epworth Sleepiness Scale (ESS) of the individuals of the SG individuals of the FFG (before and after).