Moderate continuous‐ and high‐intensity interval training elicit comparable cardiovascular effect among middle‐aged men regardless of recovery mode

Abstract

ABSTRACTTo assess the effect of active and passive intra‐interval recovery modes in time‐efficient high‐intensity interval training (HIT) on cardiorespiratory fitness, autonomic function, and endothelial function in sedentary middle‐aged men.Participants (n = 62; age: 49.5 ± 5.8 y; BMI: 29.7 ± 3.7 kg·m−2) completed the assessments of cardiorespiratory fitness, flow‐mediated dilation (FMD) and heart rate variability before being randomly allocated to control (CON; n = 14), moderate intensity continuous training (MICT; n = 15), HIT with passive (P‐HIT; n‐15), or active recovery (A‐HIT; n = 15). Participants performed thrice weekly exercise sessions for 12 weeks. MICT completed 50–60 min of continuous cycling at 60–70% heart rate (HR) maximum. HIT completed 30‐s work intervals (∼85% HR) interspaced with 2.5 min of active or passive recovery.All exercise modalities increased oxygen uptake (V̇O2) (MD: ≥ 3.1 ml·kg−1·min−1, 95%CI: 1.5–4.7 ml·kg−1·min−1; P < 0.001), power output (MD: ≥ 26 W, 95%CI: 15–37 W; P < 0.001) and cycle duration (MD: ≥ 62 s, 95%CI: 36–88 s; P < 0.001) at 85% HRM. Significant pre‐to‐post differences were observed among all exercise groups for FMD (MD: ≥ 3.4%, 95%CI: 0.3–6.5%; P < 0.05), while MICT and P‐HIT significantly increased the standard deviation of all NN intervals (SDNN) pre‐to‐post intervention (MD: ≥ 7 ms, 2–13 ms; P ≤ 0.05).Time‐efficient HIT elicits significant improvements in cardiorespiratory fitness, FMD and autonomic modulation following a thrice weekly 12‐week exercise intervention among sedentary middle‐aged men. Active recovery between successive high‐intensity intervals provided no additional benefit among this deconditioned cohort.