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Updated: Aug 25, 2025
A Real-World High-Intensity Interval Training Protocol for Cardiorespiratory Fitness Improvement
Published on: February 22, 2022
High-intensity interval training: optimizing oxygen consumption and time to exhaustion taking advantage of the
Filippo Vaccari1,2, Jacopo Stafuzza3, Nicola Giovanelli4,3
1Department of Medicine, University of Udine, P.le Kolbe 4, 33100, Udine, Italy. filippo.vaccari@uniud.it.
Purpose:
Accumulating the time near maximum aerobic power [Formula: see text] is considered to be the most effective way to improve aerobic capacity. The aims of this study were: (1) to verify whether postponing the first recovery interval improves time to exhaustion during a high-intensity interval training (HIIT) test, and (2) to verify whether a HIIT protocol with decreasing interval duration (HIDIT) is more effective in accumulating time near [Formula: see text] compared with two classical protocols with short intervals (SIHIIT) and long intervals (LIHIIT).
Methods:
Nine active males (35 ± 11 years, [Formula: see text] 52 ± 5 mL·min-1·kg-1) performed a graded exercise test on an athletic track. Critical velocity and D' were estimated from three to five high-intensity trials to exhaustion. Then, the subjects performed three trials with a single recovery interval after 30 s (Rec30s), after 3 min (Rec3min) and after exhaustion (RecTlim) to verify whether postponing the first recovery interval enhances the time to exhaustion. Finally, the subjects performed the three HIIT protocols mentioned above.
Results:
The time to exhaustion was significantly greater in RecTlim (464 ± 67 s) than in Rec3min (388 ± 48 s) (p < 0.0078) and Rec30s (308 ± 44 s) (p > 0.0001). Additionally, it was significantly greater in Rec3min than in Rec30s (p = 0.0247). Furthermore, the time accumulated near [Formula: see text] was significantly longer in HIDIT (998 ± 129 s) than in SIHIIT (678 ± 116 s) (p = 0.003) and LIHIIT (673 ± 115 s) (p < 0.031).
Conclusions:
During the trials, postponing the first recovery interval was effective in improving the time to exhaustion. Moreover, HIDIT was effective in prolonging the time near [Formula: see text].
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