Objective: Conduct a systematic review of previous meta‐analyses on exercise and sleep outcomes in adults and a meta‐analysis of studies nested within these meta‐analyses.Methods: Meta‐analyses of randomized controlled exercise interventions were included by searching nine electronic databases and cross‐referencing. Dual‐selection and data abstraction were conducted. Methodological quality of meta‐analyses was assessed using AMSTAR and quality of evidence using GRADE. Random‐effects models were used to pool results from the individual studies included in each meta‐analysis.Results: Three meta‐analyses representing 950 adults were included. Methodological quality ranged from 36% to 64% while quality of evidence was very low to low. Statistically significant improvements (P ≤ 0.05) were observed for the apnea‐hypopnea index (AHI), overall sleep quality, global score, subjective sleep, and sleep latency. The number‐needed‐to‐treat (NNT) and percentile improvements ranged from 4 to 7 and from 18.1 to 26.5, respectively. When overall sleep quality results from individual studies nested within different meta‐analyses were pooled, statistically significant standardized mean difference (SMD) improvements were observed (–0.50, 95% CI –0.72 to –0.28). The NNT and percentile improvement were 7 and 19, respectively.Conclusions: Exercise improves selected sleep outcomes in adults. To increase public health reach, a large, well‐designed, and more inclusive meta‐analysis is needed.

Statistical models for meta-analysis: A brief tutorial

OBJECTIVE: Use the meta-analytic approach to examine the effects of aerobic exercise on lipids and lipoproteins in overweight and obese adults. DATA SOURCES: (1) Computerized literature searches, (2) cross-referencing from review and original articles, (3) hand searching, and (4) expert review of reference list. STUDY SELECTION: (1) randomized controlled trials, (2) aerobic exercise ≥8 weeks, (3) adult humans ≥18 y of age, (4) all subjects overweight or obese (BMI ≥25 kg/m²), (5) studies published in journal, dissertation, or master's thesis format, (6) studies published in the English-language, (7) studies published between 1 January 1955 and 1 January 2003, (8) assessment of one or more of the following lipid and/or lipoprotein variables: total cholesterol (TC), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), and triglycerides (TG). DATA ABSTRACTION: Dual-coding by the first two authors (inter-rater agreement=0.96). RESULTS: In total, 13 studies representing 31 groups (17 exercise, 14 control), 613 subjects (348 exercise, 265 control), and up to 17 outcomes were available for pooling. Across all categories, random-effects modeling resulted in statistically significant improvements for TC (X̄±s.e.m., − 3.4±1.7 mg/dl, 95% CI, − 6.7 to − 0.2 mg/dl) and TG (X̄±s.e.m., − 16.1±7.3 mg/dl, 95% CI, − 30.2 to − 2.1 mg/dl) but not HDL (X̄±s.e.m., 1.6±0.8 mg/dl, 95% CI, − 0.02 to 3.2 mg/dl) or LDL (X̄±s.e.m., − 0.5±1.3 mg/dl, 95% CI, − 3.0 to 2.0 mg/dl). Changes were equivalent to improvements of 2% (TC), 11% (TG), 3% (HDL), and 0.3% (LDL). After conducting sensitivity analyses (each study deleted from the model once), only decreases in TG remained statistically significant. Increases in HDL were associated with increases in maximum oxygen consumption (VO_2 max in ml/kg/min, r=0.75, P=0.002) and decreases in body weight (r=0.77, P<0.001), while decreases in LDL were associated with decreases in body weight (r=0.75, P=0.009). CONCLUSIONS: Aerobic exercise decreases TG in overweight and obese adults. However, a need exists for additional randomized controlled trials in various overweight and/or obese populations above and beyond those included in our analysis.

Background: Cardiovascular disease (CVD) in women is the leading cause of mortality in the United States, and less than optimal lipid and lipoprotein levels are major risk factors for CVD. The purpose of this study was to use the meta-analytic approach to examine the effects of aerobic exercise on lipids and lipoproteins in women. Methods: Studies were retrieved via computerized literature searches, review of reference lists, hand searching selected journals, and expert review of our reference list. The inclusion of studies was limited to randomized controlled trials published in the English language literature between January 1955 and January 2003 in which aerobic exercise was used as the primary intervention in adult women aged ≥18 years. One or more of the following lipids and lipoproteins were assessed: total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG). Results: Using a random effects model, statistically significant improvements were observed for all lipids and lipoproteins (TC, ± SEM, –4.3 ± 1.3 mg/dl, 95% CI –6.9 to –1.7 mg/dl; HDL-C, ± SEM, 1.8 ± 0.9 mg/dl, 95% CI 0.1 to 3.5 mg/dl; LDL-C, ± SEM, –4.4 ± 1.1 mg/dl, 95% CI –6.5 to –2.2 mg/dl; TG, ± SEM, –4.2 ± 2.1 mg/dl, 95% CI –8.4 to –0.1 mg/dl). Reductions of approximately 2%, 3%, and 5%, respectively, were observed for TC, LDL-C, and TG, whereas an increase of 3% was observed for HDL-C. Conclusions: Aerobic exercise is efficacious for increasing HDL-C and decreasing TC, LDL-C, and TG in women.