In-bed cycling for adult intensive care patients: A systematic review and meta-analysis

Integrating in-bed cycling (IBC) into graded early mobilization is common in intensive care units (ICUs), yet findings remain mixed on whether it yields significant improvements in muscle strength, mechanical ventilation outcomes, and ICU complications.

We conducted a comprehensive search for literature published from database construction to July 31, 2025. The searched databases include PubMed, Cumulative Index to Nursing and Allied Health Literature, Web of Science, and other 8 databases. We assessed the quality of the included studies using the Cochrane Risk of Bias tool and analyzed data using RevMan 5.4 software. The Grading of Recommendations Assessment, Development and Evaluation system was used to assess the certainty of the evidence.

Data from 41 randomized controlled trials (n = 3781) show that adding passive/active IBC to routine ICU rehabilitation improves Medical Research Council (standardized mean difference [SMD] = 0.53; 95% confidence interval [CI] [0.01-1.05], P = .04), 6-minute walking distance (SMD = 0.80; 95% CI [0.14-1.45], P = .02), handgrip (SMD = 0.09; 95% CI [0.02-0.36], P = .03), and Barthel Index (SMD = 1.06; 95% CI [0.66-1.46], P < .001). It shortens MV time (SMD = -0.28; 95% CI [-0.47 to -0.10], P = .001), ICU stay (SMD = -0.32, 95% CI [-0.53 to -0.12], P = .002), and hospital stay (SMD = -0.22, 95% CI [-0.40 to -0.03], P = .02), and lowers ICU-acquired weakness (odds ratio [OR] = 0.49, 95% CI [0.37-0.67], P < .001) and delirium (OR = 0.50, 95% CI [0.33-0.77], P = .002). ICU mortality (OR = 0.95, 95% CI [0.76-1.19], P = .65) and exercise-related adverse events (OR = 0.77, 95% CI [0.53-1.14], P = .20) were not increased. Results were stable in sensitivity analyses, with very low-to-moderate certainty.

Adjunct IBC alongside routine ICU rehabilitation is associated with clinically meaningful gains in strength and functional recovery, shorter dependence on organ support and ICU stay, and lower neuromuscular and neurocognitive complications, without an evident safety penalty. These effects were robust to sensitivity analyses, though the overall certainty of evidence is very low to moderate, underscoring the need for large, well-designed trials with standardized IBC protocols, longer-term outcomes and economic evaluation.