AimsTo describe the level of physical activity 6 months after an out-of-hospital cardiac arrest (OHCA) and to explore potential risk factors of a low level of physical activity. MethodsPost-hoc analyses of the international multicentre Targeted Hypothermia versus Targeted Normothermia after Out-of-Hospital Cardiac arrest (TTM2) trial. At 6 months, survivors at 61 sites in Europe, Australia and New Zeeland were invited to a follow-up. The participants answered two questions on self-reported physical activity. Answers were categorized as a low, moderate, or high level of physical activity and further dichotomized into a low versus moderate/high level of physical activity. Potential risk factors for a low level of physical activity were collected and investigated by univariable and multivariable logistic regression. ResultsAt 6 months, 807 of 939 (86%) OHCA survivors answered the two questions of physical activity; 34% reported a low, 44% moderate and 22% high level of physical activity. Obesity (OR=1.75, 95% CI 1.10–2.77, p=0.018), mobility problems by EuroQol 5 dimensions 5 levels (OR=1.73, 95% CI 1.06–2.84, p=0.029), and cognitive impairment by Symbol Digit Modalities Test (OR=1.78, 95% CI 1.13–2.82, p=0.013) were significantly associated with a low level of physical activity in the multivariable analysis. ConclusionOne third of the OHCA survivors reported a low level of physical activity. Obesity, mobility problems, and cognitive impairment were associated with a low level of physical activity.ClinicalTrials.gov Identifier: NCT02908308