Vascular reactivity at rest and during exercise in middle-aged obese men: effects of short-term, low-intensity, exercise training

Abstract

Objective: Although increased blood flow (BF) in exercising muscles is thought to be impaired in obese subjects and may contribute to physical inactivity, data are scarce in this regard and the involvement of endothelium dysfunction remains partly hypothetical. Methods: A total of 16 middle-aged obese men (body mass index, BMIX30 kg m À2 ) and 16 normal-weight men (BMIo25 kg m À2 ), matched for age, were recruited. We used ultrasonography to compare intima-media thickness (IMT) and distensibility of the carotid artery, flow-mediated dilation (FMD), nitrate-dependent dilation (NDD) and peak BF during postischemic hyperemia in the brachial artery (a conduit artery), and leg BF during knee-extensor exercise (indicative of resistance vessel function) in obese and in normal-weight men. In addition, 10 obese men participated in an 8 week individualized low-intensity training program. Results: Compared with normal-weight men, obese men had higher carotid IMT (0.50 ± 0.01 vs 0.62 ± 0.04 mm, Po0.05) but lower carotid distensibility (0.26±0.03 vs 0.11±0.03 mm Hg À1 10 À2 , Po0.05), FMD (5.7±0.4 vs 3.3±0.5%, Po0.05) and peak BF during post-ischemic hyperemia (398 ± 52 vs 229 ± 24%, Po0.05), despite similar maximal shear rate, without NDD differences. Lower limb BF (ml min À1 100 g À1 ) increased significantly from rest to maximal exercise in both groups with lower values in obese men (at peak power, 36.9 ± 1.6 vs 31.5 þ 2.2 ml min À1 100 g À1 , Po0.05). Exercise training normalized carotid distensibility (0.14±0.04 before vs 0.23±0.03 mm Hg À1 10 À2 after training, P ¼ 0.09) and FMD (2.7±0.4 before vs 4.8±0.5% after training, Po0.05), but did not improve brachial post-ischemic peak BF or exercising leg BF. Conclusions: In obese men, conduit and resistance vessel reactivity is depressed, but a short-term low-intensity exercise training improves distensibility and endothelium dependent vasodilation in the large conduit artery, but not post ischemic or exercise muscle BF.

Insulin Resistance and not BMI is the Major Determinant of Early Vascular Impairment in Patients with Morbid Obesity

“…In the present study, the obese patients exhibited a higher intima-media thickness and a lower flow-mediated vasodilation than the healthy controls (see Table 1). Furthermore, both Vinet et al 22) and the present study demonstrated that the HOMA-IR is a predictor of vascular impairment.…”

“…Other previous reports comparing obese subjects and normal weight controls have shown that increased body fat, with a parallel increase in BMI, is linked to vascular damage [20][21][22] . In the present study, the obese patients exhibited a higher intima-media thickness and a lower flow-mediated vasodilation than the healthy controls (see Table 1).…”

Atherogenic subfractions of lipoproteins in the treatment of metabolic syndrome by physical activity and diet – the RESOLVE trial

“…The CIMT is a direct measure of atherogenesis [35], whereas the Framingham score is a probability of a cardiovascular event established from a cluster of indexes: age, smoking status, type 2 diabetes, blood pressure, LDL and HDL-cholesterol [15]. Despite observed improvements in the Framingham score and carotid-intima-media-thickness, values failed to reach the control group, but remained better than baseline.…”

Vascular smooth muscle function in type 2 diabetes mellitus: a systematic review and meta-analysis

“…Impaired endothelial function, which appears long before symptoms [10], has been consistently demonstrated in the macro-and microcirculation of individuals with type 2 diabetes (Table 1) in association with hypercholesterolaemia, hyperglycaemia, low-grade systemic inflammation and oxidative stress [11]. However, whether VSM function, usually preserved in obese individuals [12], is also impaired in those with type 2 diabetes has been debated in the last two decades, because of discrepant results in both the macro-and microcirculation (Table 1).…”