High-density lipoprotein cholesterol (HDL-C) plays a vital role in cardiovascular protection, and aerobic exercise is often recommended to increase its levels. However, previous findings have varied widely. A comprehensive meta-analysis by Kodama et al. (2007) systematically reviewed 25 randomized controlled trials to determine how exercise characteristics - such as duration, intensity, and frequency - affect HDL-C response, and which individuals are most likely to benefit.

The study found that regular aerobic exercise produced a modest but statistically significant increase in HDL-C levels, averaging 2.53 mg/dL. This effect becomes meaningful with at least 900 kcal of weekly energy expenditure or 120 minutes of exercise per week.

Notably, the duration of each exercise session emerged as the most critical factor: every additional 10 minutes of exercise was associated with an approximately 1.4 mg/dL increase in HDL-C. By contrast, exercise frequency and intensity showed no significant relationship with HDL-C change.

Certain participant characteristics also influenced results. Individuals with a BMI under 28 and total cholesterol over 220 mg/dL experienced significantly greater increases in HDL-C. This suggests that leaner individuals and those with higher baseline cholesterol respond more favorably to aerobic interventions.

Conversely, obese individuals may require combined strategies, such as dietary changes, to achieve similar benefits. These patterns held across trials with varying exercise types and durations, but only in the context of studies free from dietary or pharmacological confounders (Kodama et al., 2007).