Acute cardiac autonomic and hemodynamic responses to resistive breathing: Effect of loading type and intensity.

OBJECTIVES: This study aimed to assess the acute impact of distinct loading breathing types and intensities on cardiac autonomic function and hemodynamic responses in healthy young adults. METHODS: A randomized, crossover trial involved 28 participants who underwent inspiratory resistive breathing, expiratory resistive breathing (ERB) and combined resistive breathing, each at 30% and 60% of maximal respiratory pressures. Data on heart rate variability (HRV) and hemodynamic parameters were collected during each trial. RESULTS: The study revealed significant main and interaction effects for both the performed task and the intensity across all measured variables (all p < 0.001). ERB at 60% load demonstrated significantly higher HRV values in the standard deviation of normal-to-normal RR intervals, the square root of the mean squared difference of successive normal-to-normal RR intervals and high-frequency power, as well as significantly lower values in heart rate, stroke volume, stroke volume index, cardiac output, cardiac index, end-diastolic volume and end-diastolic volume index, compared to other loaded protocols (all p < 0.001). CONCLUSION: These findings highlight the acute effect of type-specific and load-dependent resistive breathing on cardiac autonomic and hemodynamic functions, where ERB at 60% intensity showed the most significant cardiovagal modulation while causing the least hemodynamic alterations.

Acute effect of various dosages of sugar ingestion on vascular function in offspring of hypertensive and normotensive parents.

OBJECTIVES: We aimed to study vascular function in healthy men with a parental history of hypertension compared to those without. Acute effect of various dosages of sugar ingestion on vascular function was also investigated in both groups. METHODS: Thirty-two healthy men were recruited and divided into two groups, offspring of hypertensive parents (OHT) and offspring of normotensive parents (ONT). Participants were orally given 15, 30, and 60 g of sucrose solution compared to water. Peak forearm blood flow (FBF), forearm vascular resistance (FVR), pulse wave velocity (PWV), and oxidative stress markers were measured at baseline and after sucrose intake at 30, 60, 90, and 120 min. RESULTS: At baseline, peak FBF was significantly lower (22.40 ±â€Š1.18 vs. 25.24 ±â€Š0.63 ml × dl -1  × min -1 , P  < 0.001), FVR was significantly higher (3.73 ±â€Š0.42 vs. 3.30 ±â€Š0.26 mmHg × ml -1  × dl × min, P  = 0.002), and PWV was significantly faster (6.31 ±â€Š0.59 vs. 5.78 ±â€Š0.61 m/s, P  = 0.017) in OHT than ONT. After each sucrose intake, peak FBF significantly declined and was lowest at 30 min in both groups. The reduction in peak FBF was seen in all doses of sucrose and the higher dose of sucrose intervened, the longer reduction in peak FBF observed. CONCLUSIONS: Vascular function was attenuated in healthy men with a family history of hypertension and became worse after sucrose ingestion even at the low dose. Our findings suggest that the ones, especially those with a parental history of hypertension, should reduce sugar consumption as low as possible.