Postexercise Heart Rate Recovery in Adults Born Preterm

Abstract

To evaluate postexercise heart rate recovery (HRR) in adults born preterm. We studied the association between preterm birth and postexercise HRR in 545 adults (267 women) at 23.3years of age (range 19.9-26.3years). One hundred three participants were born early preterm (<34 completed weeks), 178 late preterm (34-36), and 264 were full term (control group). HRR was calculated as change in heart rate (HR) 30seconds and 60seconds after cessation of submaximal step test and maximum HR slope during the first minute after. Mean peak HR was 159.5 bpm in the early preterm (P=.16 with controls), 157.8 bpm in the late preterm (P=.56), and 157.0 bpm in the control group. Mean HRR 30seconds after exercise was 3.2 bpm (95% CI 1.1-5.2) lower in the early preterm group and 2.1 bpm (0.3-3.8) lower in the late preterm group than the full term controls. Mean 60s HRR was 2.5 (-0.1 to 5.1) lower in the early preterm group and 2.8 bpm (0.6-4.9) lower in the late preterm group. Mean maximum slope after exercise was 0.10 beats/s (0.02-0.17) lower in the early preterm group and 0.06 beats/s (0.00-0.12) lower in the late preterm group. Our results suggest reduced HRR after exercise in adults born preterm, including those born late preterm. This suggests altered reactivation of the parasympathetic nervous system, which may contribute to cardiovascular risk among adults born preterm.