Aerobic Exercise Training Response in Preterm-Born Young Adults with Elevated Blood Pressure and Stage 1 Hypertension: A Randomized Clinical Trial

Abstract

Rationale: Premature birth is an independent predictor of long-term cardiovascular risk. Individuals affected are reported to have a lower rate of [Formula: see text]o₂ at peak exercise intensity ([Formula: see text]o_2PEAK) and at the ventilatory anaerobic threshold ([Formula: see text]o_2VAT), but little is known about their response to exercise training. Objectives: The primary objective was to determine whether the [Formula: see text]o_2PEAK response to exercise training differed between preterm-born and term-born individuals; the secondary objective was to quantify group differences in [Formula: see text]o_2VAT response. Methods: Fifty-two preterm-born and 151 term-born participants were randomly assigned (1:1) to 16 weeks of aerobic exercise training (n = 102) or a control group (n = 101). Cardiopulmonary exercise tests were conducted before and after the intervention to measure [Formula: see text]o_2PEAK and the [Formula: see text]o_2VAT. A prespecified subgroup analysis was conducted by fitting an interaction term for preterm and term birth histories and exercise group allocation. Measurements and Main Results: For term-born participants, [Formula: see text]o_2PEAK increased by 3.1 ml/kg/min (95% confidence interval [CI], 1.7 to 4.4), and the [Formula: see text]o_2VAT increased by 2.3 ml/kg/min (95% CI, 0.7 to 3.8) in the intervention group versus controls. For preterm-born participants, [Formula: see text]o_2PEAK increased by 1.8 ml/kg/min (95% CI, -0.4 to 3.9), and the [Formula: see text]o_2VAT increased by 4.6 ml/kg/min (95% CI, 2.1 to 7.0) in the intervention group versus controls. No significant interaction was observed with birth history for [Formula: see text]o_2PEAK (P = 0.32) or the [Formula: see text]o_2VAT (P = 0.12). Conclusions: The training intervention led to significant improvements in [Formula: see text]o_2PEAK and [Formula: see text]o_2VAT, with no evidence of a statistically different response based on birth history. Clinical trial registered with www.clinicaltrials.gov (NCT02723552).

Keywords: aerobic training; cardiopulmonary; exercise intervention; preterm birth; randomized clinical trial.

Figure 1.

Study flow diagram. $\dot{\text{V}}$o_2PEAK = $\dot{\text{V}}$o₂ measured at peak exercise intensity; $\dot{\text{V}}$o_2VAT = $\dot{\text{V}}$o₂ measured at the ventilatory anaerobic threshold.

Figure 2.

Forest plot showing the main effects of a 16-week aerobic training intervention in the full-study group (black), followed by the subgroup effects for term-born (green) and preterm-born (blue) young adults on the primary outcome ($\dot{\text{V}}$o_2PEAK) and secondary outcome ($\dot{\text{V}}$o_2VAT). Subgroup effects did not differ significantly on the basis of interaction analyses (P = 0.32 and P = 0.12, respectively). 95% CI = 95% confidence interval; $\dot{\text{V}}$o_2PEAK = $\dot{\text{V}}$o₂ measured at peak exercise intensity; $\dot{\text{V}}$o_2VAT = $\dot{\text{V}}$o₂ measured at the ventilatory anaerobic threshold.

Figure 3.

Forest plot of the subgroup effect of a 16-week aerobic training intervention for the post hoc analyses comparing term-born (green) and preterm-born (blue) young adults. P values represent the interaction analyses for each of the subgroup analyses. BF_VAT = breathing frequency at the ventilatory anaerobic threshold; CI_PEAK = cardiac index at peak exercise intensity; CI_VAT = cardiac index at the ventilatory anaerobic threshold; HR_VAT = heart rate at the ventilatory anaerobic threshold; SVI_PEAK = stroke volume index at peak exercise intensity; SVI_VAT = stroke volume index at the ventilatory anaerobic threshold; VE_VAT = minute ventilation at the ventilatory anaerobic threshold; VT_VAT = tidal volume at the ventilatory anaerobic threshold.