Does wave reflection explain the increase in blood pressure during leg crossing?

OBJECTIVE

To assess the effect of crossing legs at the knee level on wave reflection, as measured by the augmentation index.

METHODS

Forty-two participants crossed their legs at the knee level (popliteal fossa over the suprapatellar bursa) in the sitting position for 12 min. One trained investigator performed the measurements before, during, and after leg crossing. We used the SphygmoCor to measure the augmentation index at the radial artery and an oscillometric device to measure blood pressure (BP) at the upper arm. We calculated the differences between the uncrossed and the crossed position for the augmentation index normalized for heart rate, peripheral BP, and central BP.

RESULTS

Both peripheral systolic BP 2.5 ± 6.5 (mean ± SD) mmHg (0.5-4.6) (95% confidence interval) and peripheral diastolic BP 1.7 ± 3.8 mmHg (0.5-2.9) increased during leg crossing compared with the uncrossed position. In addition, central systolic BP 2.8 ± 5.8 (0.9-4.6) and central diastolic BP 1.8 ± 3.9 (0.5-3.0) increased, whereas no significant change in the augmentation index was observed.

CONCLUSION

Our results indicate that the increase in BP during leg crossing cannot be explained by wave reflection. We found no change in the augmentation index during leg crossing at the knee level. Central BP and peripheral BP are equally influenced by leg crossing.