Acute cardiovascular exercise diminishes the consolidation of a complex whole-body task in young adults

A single bout of cardiovascular exercise (CVE) can promote neuroplasticity in an intensity-dependent manner. Consequently, performing CVE immediately after encoding may enhance motor memory consolidation, with stronger effects reported for high intensities. However, most evidence comes from fine-motor tasks, and data on complex whole-body skills are still scarce. In this pre-registered experiment, 41 neurotypical young adults practiced a balance task used to study gross-motor learning. Immediately after encoding, we randomized participants into three groups: a high-intensity interval CVE group (90/60% W_max), a moderate-intensity interval CVE group (45/25% W_max), or a resting group. These CVE protocols have previously been shown to enhance consolidation in fine-motor tasks. To evaluate consolidation, we conducted retention tests 24 h and 7 days later and calculated relative offline changes from the end of encoding to the retention tests. Contrary to our hypothesis, both CVE groups showed reduced offline learning at the 24-hour retention test compared to rest (weighted mean CVE: 2.9%; REST: 12.5%), indicating a large effect. This negative effect was unaffected by biological sex, cardiorespiratory fitness, subjective sleep quality, and post-exercise lactate levels, but was no longer present at the 7-day retention test. Our findings suggest that post-encoding CVE may attenuate early consolidation of complex whole-body motor skills, regardless of intensity. This challenges assumptions derived from fine-motor paradigms and holds relevance for applied sport and rehabilitation contexts, warranting further investigation. We discuss possible mechanisms, including catecholamine-driven reduction of frontal brain processes and interference between overlapping neural circuits engaged by the motor task and CVE.