Cardiac effects of detraining in athletes: a narrative review.

Routine physical activity stimulates numerous morphologic and functional adaptations of the cardiac system, which are commonly referred to as exercise-induced cardiac remodeling (EICR). EICR has been well documented in elite and recreational athletes, but comparatively little is known about the "reverse" cardiac adaptations during detraining in an athletic population. To assess the morphologic and functional cardiac effects of detraining in athletes. Eligible studies were identified in PubMed from inception to May 2020. Studies were included if they assessed the cardiac effects of detraining periods in athletes. A total of 16 studies from the literature search were identified and included in this review. These studies included athletes from multiple different sporting disciplines and detraining periods ranged from 3 weeks to 13 years. Detraining periods led to significantly decreased right ventricular and left (LV) ventricular dimensions, LV mass, and LV wall thickness, but only limited changes in systolic and diastolic functional parameters were observed. From the limited data available in this population, cardiac atrophy has been observed with short periods of detraining (1-8 weeks) but often spares systolic and diastolic heart function. Supplemental exercise training during times of rehabilitation to combat cardiac regression has not been vigorously studied in athletes, so the ideal frequency, intensity, and modality of exercise needed to maintain EICR remains unclear.