The use of mental health promotion strategies by nurses to reduce anxiety, stress, and depression during the COVID-19 outbreak: A prospective cohort study

•Nurses' stress and anxiety symptoms decreased six months after the lockdown due to COVID-19.•Nurses increased the physical activity and reduced remote social contacts six months' after the lockdown due to COVID-19.•The use of mental health promotion strategies by nurses is important to reduce stress, anxiety, and depression symptoms.•Caring for nurses' mental health during the COVID-19 outbreak is a matter of public health concern.