Lawrence D. Rink

The Flow-mediated Dilation Response to Acute Exercise in Overweight Active and Inactive Men

Objective: Inflammation has been found to play a role in the etiology of cardiovascular disease as well as provoke endothelial dysfunction. Inflammatory cytokines associated with endothelial function are interleukin‐6 (IL‐6) and tumor necrosis factor‐α (TNF‐α). IL‐6 is exercise intensity dependent and has been shown to inhibit TNF‐α expression directly. The aim of this study was to investigate the interaction of IL‐6 and TNF‐α on endothelial function in response to acute exercise in overweight men exhibiting different physical activity profiles.

Accumulation of physical activity leads to a greater blood pressure reduction than a single continuous session, in prehypertension.

Background Despite limited research, the accumulation of physical activity has been recommended for the treatment of prehypertension. Objectives To compare the duration and magnitude of blood pressure reduction after accumulated physical activity with that after a single session of continuous physical activity, and to investigate sympathetic modulation as a possible mechanism for the reduction in blood pressure after each acute session. Methods Prehypertensive adults (n = 21) participated in a randomized crossover design. Ambulatory blood pressure and heart rate variability (Holter monitoring) were measured for 12 h after accumulated physical activity (4 × 10-min walks (1/h for 4 h) at 50% of VO2peak), continuous physical activity (40-min walk at 50% of VO2peak) and control treatments. Blood pressure and heart rate variability after each activity treatment were compared with the respective periods from the control treatment. Heart rate variability was correlated with reduction in blood pressure. Results Systolic blood pressure (SBP) was reduced for 11 h after accumulated physical activity (P < 0.01), and for 7 h after continuous physical activity (P < 0.05). Diastolic blood pressure (DBP) was reduced for 10 h after accumulated physical activity (P < 0.05) and for 7 h after continuous physical activity (P < 0.05). With accumulated physical activity, the differences in normalized low-frequency (r = 0.517, P < 0.01) and high-frequency (r = −0.503, P < 0.05) power were correlated with reduction in SBP and the differences in normalized low-frequency (r = 0.745, P < 0.001), high-frequency (r = −0.738, P < 0.001) powers, and low frequency: high frequency ratio (r = 0.756, P < 0.001) were correlated with reduction in DBP. With continuous physical activity, the difference in low frequency: high frequency ratio (r = 0.543, P < 0.05) was correlated with reduction in DBP. Conclusion The accumulation of physical activity appears to be more effective than a single continuous session in the management of prehypertension. Sympathetic modulation was associated with reduced blood pressure after each session.

Variability of flow-mediated dilation measurements with repetitive reactive hyperemia

To capture the response of an acute intervention, multiple post intervention measurements of flow-mediated dilation (FMD) must be performed. The effect of repetitive reactive hyperemia on endothelial function and the measurement of FMD are unknown. The purpose of this investigation was (1) to examine the effect of repetitive reactive hyperemia on brachial artery FMD and (2) to determine whether brachial artery FMD is stable during a 2-h morning period. We investigated FMD in 20 apparently healthy college students on three randomized treatment days every 30 min (T30), 60 min (T60), and 120 min (T120) throughout a 2-h morning period (08.00 h to 10.00 h). An ANOVA (p > 0.05) and ICC (>0.40) were both needed to confirm no difference among repetitive reactive hyperemia treatments. In response to repetitive reactive hyperemia, there was no difference (p = 0.307; ICC > 0.40) within the first and last FMD measurements of each treatment condition or between treatment conditions (p = 0.344; ICC > 0.40). FMD was similar (p = 0.348) throughout the 2-h morning period. In conclusion, repetitive reactive hyperemia over a 2-h period has no effect on FMD measurements in apparently healthy college students. In addition, this study found no time trends for FMD measurements during the 2-h morning period to allow for pre/post intervention FMD measurements.

A comparison between active- and reactive-hyperaemia-induced brachial artery vasodilation

The measurement of brachial artery vasodilation in response to a hyperaemic stimulus has been used extensively to assess changes in endothelial function. However, whether or not similar changes occur in response to an active hyperaemic stimulus is unknown. The purpose of the present study was to compare brachial artery vasodilation in response to an active compared with a reactive hyperaemic stimulus following a known perturbation of endothelial function. Eight apparently healthy adults were assigned to four treatment conditions in a counter-balanced design: (i) low-fat meal with active hyperaemic stimulus (LFM-A), (ii) high-fat meal with active hyperaemic stimulus (HFM-A), (iii) low-fat meal with reactive hyperaemic stimulus (LFM-R), and (iv) high-fat meal with reactive hyperaemic stimulus (HFM-R). Meals were ingested at 08:00 hours on each treatment day. Brachial artery vasodilation was assessed via ultrasound 4 h after ingestion of each meal. The active hyperaemic stimulus was induced by 5 min of rhythmic handgrip exercise, whereas reactive hyperaemia was induced by 5 min of forearm occlusion. Brachial artery vasodilation was expressed as the percentage change in diameter from baseline to post-active/reactive hyperaemia. Using a 2x2 repeated measures ANOVA, a significant stimulusxmeal interaction (P=0.025) was found. Simple main effects revealed no difference (P=0.541) in brachial artery vasodilation between LFM-A (5.75+/-1.64%) and HFM-A (6.39+/-1.45%); however, a significant decrease (P=0.014) in brachial artery vasodilation was found in the HFM-R (4.29+/-1.64%) compared with the LFM-R (7.18+/-1.13%) treatment. In conclusion, the measurement of brachial artery vasodilation in response to active hyperaemia did not detect a change in endothelial function following a single perturbation meal, whereas reactive hyperaemia did.

Characterization of the brachial artery shear stress following walking exercise

Abstract Habitual exercise provides repeated episodes of elevated vascular shear stress (SS), which may be a mechanism for repair of endothelial dysfunction in disease. Our aim was to determine the brachial artery SS during the 3–hour period following single bouts of low, moderate, and high-intensity walking exercise. In a randomized crossover design, 14 men walked for 45 minutes on a treadmill at 25%, 50% and 75% of VO2peak separated by 2–7 days. Using Doppler ultrasonography, brachial artery SS was assessed immediately after exercise and then hourly for 3 hours. High-intensity walking elicited greater (p < 0.05) post-exercise SS compared with low and moderate intensity. In addition, a 3 x 4 (intensity x time) ANOVA indicated an absence of interaction (p = 0.369) and a decline in post-exercise SS over time (p < 0.0001) which was abolished after 2 hours. Thus, we found that brachial artery SS is greatest following high-intensity walking and that the rate of decline in SS is similar across all walking intensities.

Left Ventricular Longitudinal Strain and Strain Rate Values According to Sex and Classifications of Sports in the Young University Athletes Who Participated in the 2015 Gwangju Summer Universiade

Left ventricular (LV) strain values measured by 2-dimensional speckle tracking echocardiography (2DSTE) represent global and regional myocardial functions. These values can give prognostic information, detect subclinical LV changes, and distinguish physiologic adaptation from pathologic hypertrophy

AMERICAN HEART ASSOCIATION PREPARTICIPATION CARDIOVASCULAR SCREENING OF COMPETITIVE ATHLETES HISTORY ELEMENTS APPLIED TO A DIVERSE INTERNATIONAL SCREENING PROGRAM

Background: The history portion of the American Heart Association (AHA) preparticipation evaluation (PPE) consists of 7 personal & 3 family history questions. These were developed by expert opinion & have not been evaluated in a diverse international setting. Methods: At the 2015 Summer World