Relation between body mass index and endothelium-dependent vasodilatation in healthy postmenopausal women

Vascular endothelial function and its response to moderate-intensity aerobic exercise in trained and untrained healthy young men

30 min of moderate-intensity aerobic exercise per day is recommended, but the response and adaptation of endothelial function (EF) to this exercise remains controversial. The purpose of this study was to determine the changes in EF in endurance trained and untrained individuals before and after this exercise and to compare the differences between trained and untrained individuals. Twelve endurance-trained male college athletes (trained group) and 12 untrained male college students (untrained group) performed a 30-min run at an intensity of 60% VO2max. Brachial artery flow-mediated dilation (FMD) was measured before exercise, 30 min and 60 min after exercise, and the following morning. Resting diameter and maximum diameter showed large time effects (p < 0.001, η2 = 0.533; p < 0.001, η2 = 0.502). Resting diameters at 30 and 60 min after exercise were higher than before exercise in both the untrained and trained groups (p < 0.05), and maximum diameters at 30 min after exercise were higher than before exercise in both the untrained and trained groups (p < 0.01). Resting diameter and maximum diameter also exhibited some group effects (p = 0.055, η2 = 0.157; p = 0.041, η2 = 0.176). Resting diameters and maximum diameters were higher in the trained group than in the untrained group before exercise (p < 0.05). FMD (%) showed no time, group, or time-group interaction effects. 30 min of moderate-intensity aerobic exercise can increase resting and maximal arterial diameters in both trained and untrained young men, but has no effect on FMD. Long-term endurance training has the potential to increase resting and maximal arterial diameters in young men, but not necessarily FMD.

Endothelial and exercise vasodilation are reduced in postmenopausal females with obesity versus lean and overweight

BACKGROUND

Obesity (OB) is highly prevalent in females after menopause, especially visceral adipose tissue (VAT) accumulation which contributes to endothelial dysfunction. The endothelium assists in regulating blood flow (BF) during exercise and is attenuated in females with OB. The purpose of this study was to examine upper and lower limb flow-mediated dilation (FMD) and BF regulation during graded low-intensity submaximal exercises in postmenopausal females with BMI in the lean (LN), overweight (OW) and OB categories.

METHODS

Participants were grouped by body mass index (BMI) into LN (BMI 18.5-24.9 kg/m2; n = 11), OW (BMI 25.0-29.9 kg/m2; n = 15), and OB (BMI 30.0-39.9 kg/m2; n = 13). FMD of the brachial (BA-FMD) and superficial femoral arteries (FA-FMD) were assessed. Subsequently, BF and vascular conductance (VC) in the upper (BA-BF and BA-VC) and lower limbs (FA-BF and FA-VC) were measured during separate 3-stage incremental rhythmic handgrip and plantarflexion exercises.

RESULTS

Significantly lower FA-FMD (P < 0.05) were seen in OB than LN and OW groups with no differences in BA-FMD. Increases in FA-BF and FA-VC were attenuated during the last stage of plantarflexion exercise at 30% of 1RM in OB (both P < 0.001) compared to LN and OW, while upper-body exercise vasodilation was unchanged. FA-BF and FA-VC during plantarflexion exercise were correlated to FA-FMD (FA-BF: r = 0.423, P = 0.007, FA-VC: r = 0.367, P = 0.021) and BMI (FA-BF: r = -0.386, P = 0.015, FA-VC: r = -0.456, P = 0.004).

CONCLUSION

Postmenopausal females with OB have reduced lower-limb endothelial and exercise vasodilator function during submaximal dynamic plantarflexion exercise compared to LN and OW. Our findings indicate that obesity may predict diminished leg endothelial function, BF and VC during exercise in postmenopausal females.