BACKGROUND: Performing exercise is shown to prevent cardiovascular disease, but the risk of an out-of-hospital cardiac arrest (OHCA) is temporarily increased during strenuous activity. We examined the etiology and outcome after successfully resuscitated OHCA during exercise in a general non-athletic population.

METHODS: Consecutive patients with OHCA were admitted with return of spontaneous circulation (ROSC) or on-going resuscitation at hospital arrival (2002-2011). Patient charts were reviewed for post-resuscitation data. Exercise was defined as moderate/vigorous physical activity.

RESULTS: A total of 1393 OHCA-patients were included with 91(7%) arrests occurring during exercise. Exercise-related OHCA-patients were younger (60 ± 13 vs. 65 ± 15, p<0.001) and predominantly male (96% vs. 69%, p<0.001). The arrest was more frequently witnessed (94% vs. 86%, p=0.02), bystander CPR was more often performed (88% vs. 54%, p<0.001), time to ROSC was shorter (12 min (IQR: 5-19) vs. 15 (9-22), p=0.007) and the primary rhythm was more frequently shock-able (91% vs. 49%, p<0.001) compared to non-exercise patients. Cardiac etiology was the predominant cause of OHCA in both exercise and non-exercise patients (97% vs. 80%, p<0.001) and acute coronary syndrome was more frequent among exercise patients (59% vs. 38%, p<0.001). One-year mortality was 25% vs. 65% (p<0.001), and exercise was even after adjustment associated with a significantly lower mortality (HR=0.40 (95%CI: 0.23-0.72), p=0.002).

CONCLUSIONS: OHCA occurring during exercise was associated with a significantly lower mortality in successfully resuscitated patients even after adjusting for confounding factors. Acute coronary syndrome was more common among exercise-related cardiac arrest patients.