Although the associations between chronic levels of arterial stiffness and blood pressure (BP) have been fairly well studied, it is not clear whether and how much arterial stiffness is influenced by acute perturbations in BP. The primary aim of this study was to determine magnitudes of BP dependence of various measures of arterial stiffness during acute BP perturbation maneuvers. Fifty apparently healthy subjects, including 25 young (20-40 yr) and 25 older adults (60-80 yr), were studied. A variety of BP perturbations, including head-up tilt, head-down tilt, mental stress, isometric handgrip exercise, and cold pressor test, were used to encompass BP changes induced by physical, mental, and/or mechanical stimuli. When each index of arterial stiffness was plotted with mean BP, all arterial stiffness indices, including cardio-ankle vascular index or CAVI (r = 0.50), carotid-femoral pulse wave velocity or cfPWV (r = 0.51), brachial-ankle pulse wave velocity or baPWV (r = 0.61), arterial compliance (r = -0.42), elastic modulus (r = 0.52), arterial distensibility (r = -0.32), β-stiffness index (r = 0.19), and Young's modulus (r = 0.35) were related to mean BP (all P < 0.01). Changes in CAVI, cfPWV, baPWV, and elastic modulus were significantly associated with changes in mean BP in the pooled conditions, while changes in arterial compliance, arterial distensibility, β-stiffness index, and Young's modulus were not. In conclusion, this study demonstrated that BP changes in response to various forms of pressor stimuli were associated with the corresponding changes in arterial stiffness indices and that the strengths of associations with BP varied widely depending on what arterial stiffness indices were examined.

Aging and diabetes are associated with decreased aerobic fitness, an independent predictor of mortality. Aerobic exercise is prescribed to improve aerobic fitness; however, middle-aged/older diabetic patients often suffer from mobility limitations which restrict walking. Non-weightbearing/low-impact exercise is recommended but the optimal exercise prescription is uncertain. The goal of this randomized controlled trial was twofold: 1) to test if high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT), implemented on a nonweight-bearing all-extremity ergometer, are feasible, well-tolerated and safe in middle-aged/older adults with type 2 diabetes; and 2) to test whether all-extremity HIIT is more effective in improving aerobic fitness than MICT. A total of 58 sedentary individuals with type 2 diabetes (46 to 78 years; 63±1) were randomized to all-extremity HIIT (n=23), MICT (n=19) or non-exercise control (CONT; n=16). All-extremity HIIT and MICT, performed 4×/week for 8 weeks under supervision, resulted in no adverse events requiring hospitalization or medical treatment. Aerobic fitness (VO 2peak) improved by 10% in HIIT and 8% in MICT and maximal exercise tolerance increased by 1.8 and 1.3 min, respectively (P≤0.002 vs. baseline; P≥0.9 for HIIT vs. MICT). In conclusion, all-extremity HIIT and MICT are feasible, well-tolerated and safe and result in similar improvements in aerobic fitness in middle-aged/older individuals with type 2 diabetes. These findings have important implications for exercise prescription for diabetic patients; they indicate

These results suggest that the techniques used to assess arterial stiffness may not be interchangeable in clinical and research settings and that comparisons of findings obtained with different arterial stiffness measures should be conducted with caution.

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<b><i>Background:</i></b> A variety of arterial stiffness measures have been used to assess the impacts of disease states and various interventions without clear consensus among them. One of the primary problems faced by investigators conducting systematic reviews and meta-analyses is the lack of standardized methodology with a same unit to evaluate and compare investigations using different arterial stiffness measures. Therefore, the purpose of this study was to derive and summarize standardized equations to convert commonly used image-based measures of arterial stiffness to local pulse wave velocity (PWV). <b><i>Methods:</i></b> We first conducted a literature search to obtain and summarize conversion equations in the published literature such that these equations can be found in one convenient location. Then, we generated regression equations using the data collected in a well-controlled laboratory-based study, in which all measures of arterial stiffness were obtained in 49 apparently healthy participants. <b><i>Results:</i></b> All literature-based conversion equations produced similar local PWV values and were moderately and significantly correlated with directly measured carotid-femoral PWV (cfPWV) with a Pearson’s <i>r</i> ranging from 0.41 to 0.50. The local PWV using laboratory-based equations were modestly associated with cfPWV (<i>r</i> = 0.39–0.49) with an exception of incremental elastic modulus (<i>r</i> = 0.15, <i>p</i> &#x3e; 0.05). <b><i>Conclusion:</i></b> Commonly used measures of ultrasound-based arterial stiffness can be converted to local PWV and compared with a reference standard measure of arterial stiffness.