Sleep disorders are prevalent among cancer patients. Reduced nighttime sleep, as a type of sleep disorder, diminishes quality of life and is associated with depression, anxiety disorders, fatigue and irritability. This directly impacts the musculoskeletal quality, leading to muscle weakness. Both shorter or longer sleep durations are significant factors influencing changes in body composition. These changes increase the risk of obesity and sarcopenia— a musculoskeletal disorder characterized by a generalized loss of muscle strength and mass. Cascades of anabolic and catabolic hormones, mediated by growth hormone, insulin-like growth factor I, cortisol, testosterone, and insulin— critical to the improvement and restoring muscle fibers, functionality, and strength—are influenced by sleep quality. Chronic insomnia can also disrupt the hypothalamic-pituitary-adrenal axis, leading to endocrine changes.

This narrative review aimed to analyze the influence of sleep quality on muscle strength in cancer patients.

This descriptive review focused on studies conducted between 2021 and 2025. A total of 25 studies were selected from databases including LILACS, MEDLINE via PubMed, SciELO, and PEDro. The search utilized a combination of terms and keywords with Boolean operators OR and AND. The selected descriptors were derived from the MeSH platform: Sleep Quality, Sleep Wake Disorders, Muscle Strength, and Cancer Survivors.

The results showed that sleep quality issues, such as insomnia, obstructive sleep apnea syndrome (OSAS), and excessive daytime sleepiness, are common and significant complaints among cancer patients. These issues may be related to pre-existing sleep disorders, psychological conditions associated with cancer, or side effects of cancer treatment. Reduced sleep duration and quality disrupt cellular functions by inhibiting protein synthesis pathways and activating muscle degradation pathways. Physiotherapists also face challenges in effectively screening and identifying these contributing factors.

Poor sleep quality is a significant public health concern, as it is both widespread and associated with numerous adverse effects on the quality of life of cancer patients. The use of validated assessment tools is essential to guide physiotherapeutic interventions and promote health.

This review has the potential to significantly advance oncology physiotherapy research by addressing an underexplored yet highly relevant area. Nonetheless, additional research is needed to better understand the relationship between sleep quality and muscle strength in cancer patients, and to enhance clinical practices. This review underscores the importance of evaluating these connections to identify the underlying causes of patient conditions, ultimately aiming to deliver holistic and comprehensive care.