To investigate the effect of stepwise paced breathing (PB) on pulse transit time (PTT), we collected physiological signals of electrocardiogram (ECG), respiration and arterial pulse wave during a procedure of stepwise PB, which consists of 6 different breathing rates changing in a protocol of 14.0-12.5-11.0-9.5-8.0-7.0 breath per minute (BPM), with each breathing rate lasting 3 minutes. Twenty two healthy adults involved in this experiment and the change of PTT was analyzed during the stepwise PB procedure. In our study, the PTT was measured by calculating the time interval from the R-spike of the ECG to the peaks of the second derivative of the arterial pulse wave. Ensemble empirical mode decomposition (EEMD) was applied to PTT to decompose the signal into different intrinsic mode function, and respiratory oscillation and trend component (baseline) in PTT were further extracted. It was found that the respiratory oscillations in the PTT increased with decreasing of the PB rate, and many of the subjects (14 out of 22) showed the phenomena of PTT baseline increasing during the stepwise PB procedure. The results indicated that the stepwise PB procedure induced a high level of cardiovascular oscillation and produced an accumulative effect of PTT baseline increase. As PTT is capable of predicting changes in BP over a short period of time, increase of PTT baseline indicates the decrease of blood pressure. The experiments showed that the stepwise PB procedure could reduce blood pressure for most subjects. For future work, it is necessary to develop certain indices differentiating the effectiveness of the stepwise PB procedure on the PTT baseline change, and to test the effectiveness of this stepwise PB procedure on blood pressure reduction for patients with essential hypertension.
Adult ; Blood Pressure ; Blood Pressure Determination ; Electrocardiography ; Essential Hypertension ; Humans ; Hypertension ; Pulse Wave Analysis ; Respiration ; Respiratory Rate

Objective To analyze the serum levels of medium-and long-chain free fatty acids (FFAs)in patients with hyperlipidemic non-alcoholic fatty liver disease (NAFLD) in order to shed some light on prevention and treatment of NAFLD.Methods The clinical data of 125 patients with high triglyceride (TG)levels who were treated in Hebei General Hospital from January 2011 to May 2011 were analyzed in this study.They were further divided into HF group (n =64) and H group (n =61) based on the presence of NAFLD or not.In addition,63 healthy individuals were recruited from the Central Hospital of Handan during the same period as the control group (N group).Serum medium-and long-chain FFAs were detected by gas chromatography.The body mass index (BMI),abdominal circumference,blood pressure,fasting blood glucose (FBG),and serum lipids including TG,total cholesterol (TC),high-density lipoprotein cholesterol (HDL-C),and low-density lipoprotein cholesterol (LDL-C) were measured.Results Compared with the N group,the H group had significantly higher BMI [(25.24 ± 1.41) kg/m2 vs.(24.32 ± 1.12) kg/m2,P =0.004],abdominal circumference [(84.72 ± 1.34) cm vs.(77.33 ±0.89) cm,P =0.010],and diastolic blood pressure [(77.35±1.21) mmHgvs.(75.21 ±1.61) mmHg,P=0.014]; also,the serum TG [(2.86±0.55) mmol/Lvs.(0.93±0.27) mmol/L,P=0.000] andTC levels [(4.56±0.66) mmol/Lvs.(4.36±0.47) mmol/L,P=0.000],serum myristic acid (C14∶0) [(0.49±0.04)％ vs.(0.36±0.01)％,P=0.011],palmitic acid (C16 ∶ 0) [(18.36 ± 0.47) ％ vs.(15.97 ± 0.30) ％,P =0.000],palmitoleic acid (C16∶ 1) [(1.00±0.12)％ vs.(0.58±0.02)％,P=0.001],and oleic acid (C18 ∶ 1) [(18.20±0.70) ％ vs.(12.23 ± 0.37) ％,P =0.000] all significantly increased,while stearic acid (C18 ∶ 0) [(7.52 ±0.22)％ vs.(8.15 ±0.28)％,P=0.012],eicosadienoic acid (C20 ∶ 2) [(0.61 ±0.07)％ vs.(1.03 ±0.17) ％,P =0.000],eicosatrienoic acid (C20 ∶ 3) [(1.77 ± 0.15) ％ vs.(2.49 ± 0.18) ％,P =0.002],and docosahexenoic acid (C22 ∶ 6) [(1.44 ± 0.08) ％ vs.(1.67 ± 0.09) ％,P =0.014] significantly decreased.Compared with the H group,the HF group had significantly higher weight [(85.76 ± 3.10) kg vs.(71.45 ±2.88) kg,P =0.003],abdominal circumference [(96.30 ±2.05) cm vs.(84.72 ± 1.34) cm,P=0.000],systolic blood pressure [(117.12 ±1.15) mmHg vs.(113.23 ±1.25) mmHg,P=0.009],and diastolic blood pressure [(79.54 ± 1.42) mmHg vs.(77.35 ± 1.21) mmHg,P =0.016],whereas the sreum FGB,TG,TC,HDL-C,and LDL-C showed no significant differentces; serum palmitic acid (C16 ∶ 0)[(19.54 ± 0.30) ％ vs.(18.36 ± 0.47) ％,P =0.000] also significantly increased.The serum level of eicosadienoic acid (C20 ∶ 2) in HF group was between that in N group and H group [(0.78 ± 0.09) ％ vs.(1.03 ±0.17)％,(0.78±0.09)％ vs.(0.61 ±0.07)％,both P=0.000].Conclusions The increased serum level of palmitic acid may be a risk factor for NAFLD.Reducing saturated fatty acids and increasing unsaturated acids in diets may be helpful for preventing NAFLD.