Coherence Breathing Before Cardiopulmonary Exercise Testing

This randomized crossover trial will examine the acute effects of pre-exercise coherence breathing on cardiopulmonary exercise responses in recreationally active adults. Participants will complete two experimental conditions in randomized order: 5 minutes of guided coherence breathing and 5 minutes of quiet seated spontaneous breathing. Following each condition, participants will perform a standardized treadmill warm-up and a maximal cardiopulmonary exercise test. Outcomes will include oxygen consumption, heart rate, heart rate recovery, perceived exertion, time to completion, and heart rate variability. The findings may help determine whether coherence breathing can serve as an effective autonomic priming strategy before a bout of maximal exercise

Inclusion Criteria: * Adults aged 19 to 45 years. * Any biological sex. * Recreationally active, defined as accumulating at least 3 hours per week of moderate-to-vigorous physical activity. * Able to perform maximal cardiopulmonary exercise testing on a treadmill. * Able to provide informed consent. * Cleared for moderate-to-vigorous physical activity based on the PAR-Q+ (or PAR-Q 2023). Exclusion Criteria: * Accumulate less than 3 hours per week of moderate-to-vigorous physical activity. * Presence of a health condition that contraindicates maximal exercise testing, including: Cardiovascular disease. Pulmonary disease. Metabolic disorders. Neuromuscular disorders. Orthopedic limitations that impair exercise performance. * Acute illness that would interfere with participation or exercise testing. * Inability or unwillingness to complete study procedures. * Inability or unwillingness to provide informed consent. * Not cleared for moderate-to-vigorous physical activity based on the PAR-Q+ (or PAR-Q+ 2023).