Department of Pediatrics, University of Wisconsin-Madison, Madison, WI, USA.
Department of Kinesiology, University of Wisconsin-Madison, Madison, WI, USA.
Eur J Appl Physiol. 2019 Apr;119(4):857-866. doi: 10.1007/s00421-019-04075-z. Epub 2019 Jan 11.
The long-term implications of premature birth on autonomic nervous system (ANS) function are unclear. Heart rate recovery (HRR) following maximal exercise is a simple tool to evaluate ANS function and is a strong predictor of cardiovascular disease. Our objective was to determine whether HRR is impaired in young adults born preterm (PYA).
Individuals born between 1989 and 1991 were recruited from the Newborn Lung Project, a prospectively followed cohort of subjects born preterm weighing < 1500 g with an average gestational age of 28 weeks. Age-matched term-born controls were recruited from the local population. HRR was measured for 2 min following maximal exercise testing on an upright cycle ergometer in normoxia and hypoxia, and maximal aerobic capacity (VO) was measured.
Preterms had lower VO than controls (34.88 ± 5.24 v 46.15 ± 10.21 ml/kg/min, respectively, p < 0.05), and exhibited slower HRR compared to controls after 1 and 2 min of recovery in normoxia (absolute drop of 20 ± 4 v 31 ± 10 and 41 ± 7 v 54 ± 11 beats per minute (bpm), respectively, p < 0.01) and hypoxia (19 ± 5 v 26 ± 8 and 39 ± 7 v 49 ± 13 bpm, respectively, p < 0.05). After adjusting for VO, HRR remained slower in preterms at 1 and 2 min of recovery in normoxia (21 ± 2 v 30 ± 2 and 42 ± 3 v 52 ± 3 bpm, respectively, p < 0.05), but not hypoxia (19 ± 3 v 25 ± 2 and 40 ± 4 v 47 ± 3 bpm, respectively, p > 0.05).
Autonomic dysfunction as seen in this study has been associated with increased rates of cardiovascular disease in non-preterm populations, suggesting further study of the mechanisms of autonomic dysfunction after preterm birth.
早产儿出生对自主神经系统（ANS）功能的长期影响尚不清楚。最大运动后心率恢复（HRR）是评估 ANS 功能的简单工具，也是心血管疾病的强有力预测指标。我们的目的是确定早产儿（PYA）的年轻人的 HRR 是否受损。
从 1989 年至 1991 年出生的新生儿肺项目中招募参与者，这是一个前瞻性随访队列，研究对象为出生体重<1500 克、平均胎龄 28 周的早产儿。从当地人群中招募年龄匹配的足月出生对照组。在常氧和低氧环境下，通过直立式自行车测力计进行最大运动测试后，测量 2 分钟的 HRR，测量最大有氧能力（VO）。
早产儿的 VO 低于对照组（分别为 34.88±5.24 和 46.15±10.21ml/kg/min，p<0.05），并且在常氧和低氧环境下，在 1 分钟和 2 分钟的恢复期间，与对照组相比，HRR 较慢（绝对值下降分别为 20±4 和 31±10 以及 41±7 和 54±11 次/分钟（bpm），p<0.01）和低氧（19±5 和 26±8 以及 39±7 和 49±13 bpm，分别为，p<0.05）。调整 VO 后，在常氧下的 1 分钟和 2 分钟恢复时，早产儿的 HRR 仍然较慢（分别为 21±2 和 30±2 以及 42±3 和 52±3 bpm，p<0.05），但在低氧下则没有（分别为 19±3 和 25±2 以及 40±4 和 47±3 bpm，p>0.05）。
本研究中观察到的自主神经功能障碍与非早产儿人群中心血管疾病发生率增加有关，这表明进一步研究早产儿后自主神经功能障碍的机制。
