Guio de Prada V, Ortega JF, Ramirez-Jimenez M, Morales-Palomo F, Pallares JG, Mora-Rodriguez R. Training intensity relative to ventilatory thresholds determines cardiorespiratory fitness improvements in sedentary adults with obesity.
Eur J Sport Sci 2018;
19:549-556. [PMID:
30381027 DOI:
10.1080/17461391.2018.1540659]
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Abstract
The aim of the present study was to study if training intensity relative to ventilatory thresholds (VTs) determines the improvements in cardiorespiratory fitness (CRF) in middle-aged sedentary individuals with obesity. Before and after 16-weeks of HIIT (43-min alternating bouts at 70/90% of HRMAX), oxygen consumption ( V˙ O2) and heart rate (HR) at ventilatory threshold 1 ( V˙ O2VT1, HRVT1), ventilatory threshold 2 ( V˙ O2VT2, HRVT2) and at maximal effort ( V˙ O2MAX, HRMAX) were assessed during a graded cycle-ergometer exercise test. Retrospectively, participants were divided into two groups based on whether training intensities were under (UNDER; n = 39) or over (OVER; n = 37) VT1 and VT2. At baseline, age, body composition, V˙ O2VT1, V˙ O2VT2, and HRMAX were similar in both groups. However, V˙ O2MAX was higher in OVER (P = 0.033), whereas HRVT1 and HRVT2 were higher in UNDER (P < 0.05). V˙ O2MAX (9.0%) and HRMAX (2.2%) improved similarly in both groups. V˙ O2VT1 and V˙ O2VT2 improved with training in both groups (P < 0.001) but the improvement was larger in OVER versus UNDER in V˙ O2VT1 (P = 0.013) and tended to be higher in V˙ O2VT2 (P = 0.068). HRVT1 increased only in OVER (P < 0.001), whereas HRVT2 did not change in any group (P = 0.248). A 16-week programme of HIIT improves V˙ O2MAX similarly in individuals training at intensities over or under their VTs. However, individuals training over their VTs showed a larger improvements in V˙ O2VT1 expanding exercise workloads fuelled by oxidative metabolism.
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