Zheng et al. 2022, Short- and long-term detraining and maximal oxygen uptake in athletes

This 21-study meta-analysis quantified VO₂max losses across detraining durations in trained athletes: short-term cessation (≤30 days) produced a mean decline of approximately 3.93% (ES = −0.62), while long-term cessation (>30 days) produced a larger decline of approximately 9.43% (ES = −1.42). Younger athletes and those with higher pre-detraining fitness experienced greater absolute losses during prolonged cessation; maintaining partial training attenuated long-term but not short-term losses. Strong.