In T1D, nocturnal HRV can reflect early autonomic alterations. While habitual physical activity is often linked to better HRV, fewer studies have examined the acute (same-day) effect of MVPA on nocturnal HRV in real-life conditions, while accounting for glycaemic exposure. Adults with T1D without clinical autonomic neuropathy were monitored in daily life using continuous glucose monitoring (CGM), accelerometery, and overnight RR recordings. Nocturnal HRV was extracted from a 5-minute slow-wave sleep (SWS) segment. Glycaemic exposure was described over an upstream window (wake-up to SWS onset) and a concomitant window (the 5-minute SWS segment). Linear mixed models were used to assess associations between nocturnal HRV outcomes and same-day MVPA, habitual MVPA (mean weekly MVPA), and glycaemic exposure (see paper for details). The data made available on recherche data gouv correspond to the single dataset used for these analyses. Access to the data can also be requested from Elsa Heyman. In this study, higher habitual activity was associated with higher nocturnal HRV, whereas higher same-day MVPA was associated with lower nocturnal HRV indices, particularly with greater upstream time spent >13.9 mmol.L-1. In conclusion, regular physical activity should be encouraged, and on very active days, strategies to limit time spent in marked hyperglycaemia may help support nocturnal autonomic recovery.