Effects of subsequent high-intensity interval training on vascular function and cardiovascular risk in ageing males

Ageing is associated with an increased cardiovascular (CV) risk profile, including reduced vascular function and poorer blood lipid profiles. Lifelong exercise may help preserve these CV risk factors and recent evidence suggests high intensity interval training (HIIT) may have beneficial effects on these markers despite reductions in exercise duration and frequency
PURPOSE: To examine the effects of a 7 week HIIT training programme following an initial 6 week preconditioning (PC) plan on flow mediated dilation (FMD), blood lipids and blood pressure (BP) in ageing males.
METHODS: Thirty-nine healthy aged males were assessed at baseline (A) and assigned to either sedentary males (UT) (n=22, age 62.4 + 5.4 yrs) or lifelong exercisers (TR) (n=17, 60.4 + 5.2 yrs). UT underwent 6 weeks of PC whilst TR maintained their normal exercise regime until reassessment (B). Subsequently, both groups underwent 7 weeks of HIIT once every 5 days before final assessment (C). Training consisted of six 30’s bouts of cycling interspersed with 3 min active recovery. During assessments, BP was assessed manually and blood sampled following 30-min supine rest. Subsequently, FMD was assessed in the brachial artery and analysed using edge detection software. Data were analysed comparing group means utilising a mixed design ANOVA followed by post-hoc Tukey test and students t-test.
RESULTS: No changes occurred in FMD for UT following PC or in UT and TR following HIIT. At baseline UT had lower HDL compared to TR (1.29 ± 0.37 mmol.L-1 v 1.6 ± 0.41 mmol.L-1; p < 0.05) and higher triglycerides (1.91 ± 1.00 mmol.L-1 v 1.16 ± 0.71 mmol.L-1; p < 0.05). Total cholesterol, LDL, HDL and free cholesterol were not different between groups. Following 6 weeks of PC HDL remained significantly lower in UT (1.35 ± 0.36 mmol.L-1v 1.57 ± 0.26 mmol.L-1) and following 7 weeks of HIIT there were no differences in any measure of blood lipids between UT and TR. At baseline, systolic BP (SBP) was lower in TR than UT (129.5 ± 10.3 mmHg v 139.5 ± 9.4 mmHg). SBP at C was not different between groups due to a reduction in UT (131.3 ± 10.9 mmHg).
CONCLUSION: The present study indicates that PC followed by 7 weeks HIIT improves blood lipid profiles and resting blood pressure in previously sedentary older men. Despite these changes, training status shows to have no effect on FMD derived endothelial function.