Straining to void is widely regarded as a clinical indicator of bladder outlet obstruction (BOO) in men with lower urinary tract symptoms (LUTS). However, the physiological significance of this behaviour remains poorly understood. This review examines the role of straining during the voiding cycle and evaluates current evidence regarding its relationship with BOO. Straining represents a voluntary increase in intra-abdominal pressure that may occur at different stages of micturition. Studies comparing patient-reported straining with urodynamic findings demonstrate poor correlation, and the prevalence of the symptom does not differ significantly between obstructed and unobstructed individuals. Furthermore, straining may persist after surgical relief of obstruction, suggesting that it may represent behavioural or compensatory mechanisms rather than mechanical obstruction. Overall, available evidence indicates that straining is a non-specific finding with limited diagnostic value for BOO and should be interpreted alongside objective urodynamic assessment. PATIENT SUMMARY: We reviewed research on why some people strain when passing urine. Straining can occur in people with and without bladder outlet blockage and may simply reflect a habit or a way of to help the bladder empty. This means that straining alone is not a reliable sign of obstruction.
European urology focus. 2026 Jun 17 [Epub ahead of print]
Paulina Bueno Garcia-Reyes, D Carolina Ochoa, Abdulmalik Alkhamis, Marcus J Drake
Bristol Urological Institute, Southmead Hospital, Bristol, UK. Electronic address: ., Bristol Urological Institute, Southmead Hospital, Bristol, UK., Department of Surgery and Cancer, Imperial College, London, UK.