A. Lovering1, N. Safdari1, T. Olson1, J Duke2

1University of Oregon, Eugene, OR; 2Northern Arizona University, Flagstaff, AZ

PURPOSE: To determine the impact of preterm birth history and sex on maximal oxygen consumption (VO2max). METHODS: Subjects born full term (>37 weeks postmenstrual age, n = 20 [13 male]; CONT) and subjects born <32 weeks of postmenstrual age, n = 35 (22 male); (PRET) were included in this retrospective analysis. Incremental cycle ergometer exercise until volitional exhaustion was performed to determine VO2max. Percent predicted values were determined using the FRIEND consortium data equation: VO2max(ml/kg/min) = 79.9 – (0.39 x age) – (13.7 x sex [0=male; 1= female]) – (0.127 x weight [lbs]); Myers et al. Prog in Cardiovasc Dis2016. All comparisons were unpaired, two-tailed T-tests, significance set to p<0.05. Respiratory limitations to exercise have been suggested as a possible contributor to reduced aerobic exercise capacity in PRET subjects. Thus, exercise-induced flow limitation (EFL) as a percentage of tidal volume at 90% of VO2maxwas examined as a potential explanation for variability in VO2maxin the PRET males and females. We computed Pearson product-moment correlation coefficients to determine the relationships between EFL and VO2max. RESULTS: The PRET group mean (SD) VO2maxwas 38.8 (11.7) ml/kg/min vs 47.3 (7.2) ml/kg/min in the CONT group, p=0.005. The PRET group mean (SD) % predicted VO2maxwas 81.7 (19.1) % vs 103.5 (11.2) % in the CONT group, p=0.0002. Female PRET mean (SD) VO2maxwas 30.0 (7.1) ml/kg/min vs 42.6 (2.6) ml/kg/min in the CONT group, p=0003. The Female PRET mean (SD) % predicted VO2maxwas 74.3 (13.2) % vs 105.4 (7.1) % in the CONT group, p=000003. Male PRET mean (SD) VO2maxwas 44.0 (10.9) ml/kg/min vs 49.9 (7.7) ml/kg/min in the CONT group, p =0.1. The Male PRET mean (SD) % predicted VO2maxwas 86.1 (20.8) % vs 102.6 (13.1) % in the CONT group, p=0.015. EFL was not correlated with %predicted VO2maxin 1) all PRET subjects (r= 0.008), 2) Female PRET subjects (r= -0.06), or 3) Male PRET subjects (r = -0.02). CONCLUSION: Using modern prediction equations for VO2maxthat are not population-specific, have a normal distribution, and are well represented by women, we found that maximal aerobic capacity, absolute and as a percent predicted, is significantly reduced in both PRET men and PRET women. Our data suggest that the lower VO2maxis not related to EFL in either PRET men or women.

Support: American Heart Association.

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