Relation of Aortic Waveforms with Gut Hormones following Continuous and Interval Exercise among Older Adults with Prediabetes

Prediabetes raises cardiovascular disease risk, in part through elevated aortic waveforms. While insulin is a vasodilatory hormone, the gut hormone relation to aortic waveforms is less clear. We hypothesized that exercise, independent of intensity, would favor aortic waveforms in relation to gut hormones. Older adults (61.3 ± 1.5 yr; 33.2 ± 1.1 kg/m²) with prediabetes (ADA criteria) were randomized to undertake 60 min of work-matched continuous (CONT, n = 14) or interval (INT, n = 14) exercise for 2 wks. During a 180 min 75-g OGTT, a number of aortic waveforms (applanation tonometry) were assessed: the augmentation pressure (AP) and index (AIx75), brachial (bBP) and central blood pressure (cBP), pulse pressure (bPP and cPP), pulse pressure amplification (PPA), and forward (Pf) and backward pressure (Pb) waveforms. Acylated-ghrelin (AG), des-acylated ghrelin (dAG), GIP, and GLP-1_active were measured, and correlations were co-varied for insulin. Independent of intensity, exercise increased VO₂peak (p = 0.01) and PPA_120min (p = 0.01) and reduced weight (p < 0.01), as well as AP_120min (p = 0.02) and AIx75_120min (p < 0.01). CONT lowered bSBP (p < 0.02) and bDBP (p < 0.02) tAUC_180min more than INT. There were decreases dAG_0min related to Pb_120min (r = 0.47, p = 0.03), cPP_120min (r = 0.48, p = 0.02), and AP_120min (r = 0.46, p = 0.02). Declines in AG tAUC_60min correlated with lower Pb_120min (r = 0.47, p = 0.03) and cPP_120min (r = 0.49, p = 0.02) were also found. GLP-1_{active 0min} was reduced associated with lowered AP_180min (r = 0.49, p = 0.02). Thus, while CONT exercise favored blood pressure, both intensities of exercise improved aortic waveforms in relation to gut hormones after controlling for insulin.