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Updated: Oct 26, 2025

A Real-World High-Intensity Interval Training Protocol for Cardiorespiratory Fitness Improvement
Published on: February 22, 2022
Is high-intensity interval training harmful to health?
Niklas Joisten1, Sebastian Gehlert2, Philipp Zimmer1
1Division of Performance and Health (Sports Medicine), Institute for Sport and Sport Science, Technical University Dortmund, Dortmund, Germany.
Abstract:
High-intensity interval training (HIIT) is a common method to increase performance and promote health in elite sports, rehabilitation, and disease prevention. Flockhart et al. suggest a limit of HIIT above which detrimental effects on metabolic health emerge. We put these findings into context and assess the evidence that HIIT might be harmful.
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