The Effects of Exclusive Walking on Lipids and Lipoproteins in Women with Overweight and Obesity: A Systematic Review and Meta-Analysis

OBJECTIVE

To evaluate the effects of walking, independent of diet and weight-loss, on lipids and lipoproteins in women with overweight and obesity.

DATA SOURCE

Academic Search Complete, Alternative Health Watch, Global Health, Health Source, CINAHL, MEDLINE, EMBASE, SportDiscus, and ProQuest.

STUDY INCLUSION AND EXCLUSION CRITERIA

(1) experiment-control design; (2) women with overweight or obesity; (3) walking as the experiment's independent variable; (4) four or more weeks; and (5) pre- to post-assessment of lipids and/or lipoproteins. Excluded studies reported use of lipid-lowering medication, diet or other modes of physical activity, and alternative interventions as the control.

DATA EXTRACTION

Data extraction and study quality were completed by the first 2 authors using the Cochrane review protocol and risk of bias assessment.

DATA SYNTHESIS

Raw mean difference between the experiment and control groups using a random effects model.

RESULTS

Meta-analyses of 21 interventions (N = 1129) demonstrated exclusive walking improves total cholesterol (raw mean difference = 6.67 mg/dL, P = .04) and low-density lipoproteins (raw mean difference = 7.38 mg/dL, P = .04). Greater improvement in total cholesterol, triglycerides, high-density lipoproteins, and low-density lipoproteins existed in women with obesity.

CONCLUSIONS

Exclusive walking aids in normalizing total cholesterol and LDLs in women with overweight and obesity. Exclusive walking can be used as a non-pharmacologic therapy, which may have positive clinical outcomes for individuals who especially struggle with diet and weight-reduction.

Effects of exercise accumulation on plasma lipids and lipoproteins

Debate exists as to whether improvements in some cardiometabolic risk factors following exercise training result more from the last session of, or from an accumulation of, exercise sessions. This study was designed to compare the effect of a single exercise session with 3 consecutive days of exercise on triglyceride (TG), high-density lipoprotein-cholesterol (HDL-C), and low-density lipoprotein-cholesterol (LDL-C). Twelve young adult (aged 22.5±2.5 years), overweight (body mass index=29.7±4 kg·m(-2)), sedentary, black (n=5) and white (n=7) men (n=6) and women (n=6) completed, in random order, a single treadmill exercise session at 60% maximal oxygen uptake for 90 min (1EX), accumulated exercise sessions (same as for 1EX) for 3 consecutive days (3EX), and a control protocol (no exercise for 6 days). Plasma samples were collected from baseline through 24, 48, and 72 h postexercise. Significant treatment-by-time interactions (p<0.05) existed in HDL-C and LDL-C. Postexercise responses of HDL-C differed at 48 h (1EX: -3.6, 3EX: +3.7 mg·dL(-1)) and 72 h (1EX: -1.7, 3EX: +3.2 mg·dL(-1)). LDL-C responses differed at 48 h (1EX: -16, 3EX: +6 mg·dL(-1)). Although not statistically significant, TG concentrations decreased by 29% at 24 h after 3EX, compared with -7% after 1EX. An inverse relationship between baseline and postexercise reduction in TG was present with 3EX (r=-0.655; p<0.05). In conclusion, 3EX increased HDL-C and decreased TG more than 1EX, while the decrease in LDL-C after 1EX was suppressed. Blood lipid panel changes may be due to more accumulated effects over time rather than just a result of the most recent exercise session.