A comprehensive 12-month study from the University of South Australia has quantified what many runners have long suspected: poor sleep quality is a significant and independent risk factor for running injuries. The research found that runners who reported consistently poor sleep were 1.78 times more likely to sustain an injury than those with stable, good-quality sleep — translating to a 68% probability of injury over a 12-month period for poor sleepers.
The study tracked sleep quality, training load, and injury incidence across a large cohort of recreational and competitive runners, controlling for confounding variables including weekly mileage, training intensity, age, and previous injury history. The strength of the sleep-injury association persisted even after accounting for these factors, suggesting that sleep quality is not merely a proxy for overtraining but an independent contributor to injury risk.
The physiological pathways are well documented. Sleep is when the body performs the majority of its tissue repair and adaptation. Growth hormone, which is critical for muscle and tendon recovery, is released primarily during deep sleep. Chronic sleep disruption impairs this recovery process, leading to accumulated micro-damage that eventually manifests as overuse injuries — the category that accounts for the vast majority of running injuries.
The practical implications for runners are clear. Sleep hygiene deserves the same attention as training plans, nutrition, and equipment choices. The researchers recommend that runners prioritise seven to nine hours of quality sleep per night, maintain consistent sleep and wake times, and treat persistent sleep disruption as a training-limiting factor that warrants professional attention. For coaches, monitoring athletes' sleep quality may prove as valuable as tracking weekly mileage in predicting and preventing injuries.