Early post-discharge physical activity after myocardial infarction: safe and not linked to adverse outcomes

Abstract Background Early mobilisation after myocardial infarction (MI) is increasingly common as hospital stays shorten, leading to a two- to three-fold increase in physical activity (PA) immediately after discharge. Yet, evidence on the safety and prognostic implication of this early PA is scarce, with current PA restrictions mainly based on precautionary concerns rather than data. Purpose This study investigated whether PA performed in the first week after discharge following MI is associated with short-term (1, 3 and 6 months) cardiovascular outcomes. We further explored how post-discharge PA relates to habitual pre-admission PA and whether both predict long-term (5-year) prognosis. We hypothesised that early post-discharge PA is safe, while higher pre-admission PA confers long-term protection. Methods In this prospective cohort study, 165 patients with MI (65±10 years, 65% male) were monitored during the first week post-discharge using thigh-worn accelerometers and dichotomised into high or low PA levels. The primary outcome was Major Adverse Cardiovascular Events (MACE) at 1, 3, and 6 months post-discharge. Relative risks (RR) were estimated using modified Poisson regression models, adjusted for pre-admission PA, length of stay, and peak high-sensitive cardiac Troponin-T. Pre-admission PA was assessed with the validated Short Questionnaire to Assess Health-enhancing Physical Activity (SQUASH) questionnaire, whereas Cox proportional hazards regression was used to assess outcomes during long-term follow-up. Results Within the first month post-discharge, no MACE occurred in the high post-discharge PA group versus five MACE in the low PA group. At 3 and 6 months, MACE incidence remained comparable across groups (3 months: 6.1% vs. 6.0%, RR 1.0 95%CI: 0.3-3.4; 6 months: 8.5% vs. 8.4%, RR 1.0 95%CI: 0.4-2.8). Sensitivity analyses showed no association between higher levels of vigorous PA and MACE risk. No association was observed between pre-admission and post-discharge PA (P0.05). Over 5 years, higher pre-admission PA was independently associated with improved MACE-free survival (adjusted HR 0.5 95%CI: 0.3-0.9), whereas post-discharge PA was not associated with long-term MACE risk. Conclusions Early post-discharge PA in the first week after MI was not associated with adverse cardiovascular events, even at higher intensities. Post-discharge PA levels did not reflect pre-admission PA habits, underscoring that recovery behaviour represents a distinct phase of adaptation rather than continuity of prior lifestyle. Conversely, pre-admission PA was strongly predictive of long-term cardiovascular protection. Together, these findings support early mobilisation, underscore the prognostic value of lifelong physical activity, and call for evidence-based post-discharge guidance to bridge the gap until formal cardiac rehabilitation begins.Graphical AbstractFor image description, please refer to the figure legend and surrounding text.