['To assess the association between self-perceived exercise exertion before bedtime and objectively measured sleep.', 'Fifty-two regularly exercising young adults (mean age, 19.70\u2009years; 54% females) underwent sleep electroencephalographic recordings 1.5\u2009h after completing moderate to vigorous exercise in the evening. Before sleeping, participants answered questions regarding degree of exertion of the exercise undertaken.', 'Greater self-perceived exertion before bedtime was associated with higher objectively assessed sleep efficiency (r\u2009=\u20090.69, P\u2009<0.001); self-perceived exertion explained 48% of the variance in sleep efficiency (R2\u2009=\u20090.48). Moreover, high self-perceived exercise exertion was associated with more deep sleep, shortened sleep onset time, fewer awakenings after sleep onset, and shorter wake duration after sleep onset. Multiple linear regression analysis showed that objective sleep efficiency was predicted by increased exercise exertion, shortened sleep onset time, increased deep sleep, and decreased light sleep.'] Is high self-perceived exercise exertion before bedtime associated with greater objectively assessed sleep efficiency?