School of Exercise and Nutritional Sciences, San Diego State University, San Diego, California, USA.
Physiol Rep. 2023 May;11(10):e15693. doi: 10.14814/phy2.15693.
When people stand still, they exhibit a phenomenon called postural sway, or spontaneous movement of the body's center of pressure, which is related to balance control. In general females show less sway than males, but this difference only begins to appear around puberty, pointing to different levels of sex hormones as one potential mechanism for sway sex differences. In this study, we followed cohorts of young females using oral contraceptives (n = 32) and not using oral contraceptives (n = 19), to investigate associations between estrogen availability and postural sway. All participants visited the lab four times over the putative 28-day menstrual cycle. At each visit, we performed blood draws to measure plasma estrogen (estradiol) levels, and tests of postural sway using a force plate. During late follicular and mid-luteal phase, estradiol levels were lower in participants using oral contraceptives (mean differences [95% CI], respectively: -231.33; [-800.44, 337.87]; -613.26; [-1333.60, 107.07] pmol/L; main effect p < 0.001), reflecting expected consequences of oral contraceptive use. Despite these differences, postural sway was not significantly different between participants who were using oral contraceptives and participants who were not (mean difference: 2.09 cm; 95% CI = [-1.05, 5.22]; p = 0.132). Overall, we found no significant effects of the estimated menstrual cycle phase-or absolute levels of estradiol-on postural sway.
当人们静止站立时，会出现一种称为姿势摆动的现象，即身体重心的自发性移动，这与平衡控制有关。一般来说，女性的摆动幅度小于男性，但这种差异仅在青春期左右开始出现，这表明不同水平的性激素可能是摆动性别差异的一个潜在机制。在这项研究中，我们跟踪了使用口服避孕药（n=32）和不使用口服避孕药（n=19）的年轻女性队列，以研究雌激素可用性与姿势摆动之间的关联。所有参与者在假定的 28 天月经周期内四次访问实验室。每次访问时，我们进行采血以测量血浆雌激素（雌二醇）水平，并使用测力板进行姿势摆动测试。在卵泡晚期和黄体中期，使用口服避孕药的参与者的雌二醇水平较低（平均差异[95%CI]，分别为：-231.33；[-800.44, 337.87]；-613.26；[-1333.60, 107.07] pmol/L；主要效应 p<0.001），这反映了口服避孕药使用的预期后果。尽管存在这些差异，但使用口服避孕药和不使用口服避孕药的参与者之间的姿势摆动没有显著差异（平均差异：2.09cm；95%CI=[-1.05, 5.22]；p=0.132）。总体而言，我们没有发现估计的月经周期阶段或雌二醇的绝对水平对姿势摆动有显著影响。
