Impact of aerobic training on body composition profiles among postmenopausal women with overweight or obesity: a systematic review and dose-response meta-analysis.

TL;DR

Aerobic exercise reduces body weight, fat mass, and waist circumference in postmenopausal women with overweight or obesity, but the effects are modest (average 2 kg weight loss) and evidence certainty varies from low to moderate.

What the Study Found

Researchers analyzed 16 randomized controlled trials involving 1,571 postmenopausal women to examine how aerobic exercise affects body composition. The analysis used meta-analytical methods designed to handle multiple outcomes from individual studies, ensuring that dependent effect sizes didn't artificially inflate results.

Compared to no exercise, aerobic training produced the following changes:

Lean body mass showed a positive but imprecise effect (0.72 kg increase, P=0.14), meaning the estimate was too uncertain to draw firm conclusions.

The dose-response analysis, which examined whether more exercise produces proportionally greater benefits, revealed no clear non-linear relationship. However, some fitted curves suggested possible plateau effects, indicating that increasing exercise volume may yield diminishing returns. Interestingly, baseline age emerged as a moderating factor: younger postmenopausal women showed greater reductions in body weight and BMI compared to older participants.

The researchers noted significant limitations in the underlying trials. Many studies lacked clear reporting of exercise adherence, dietary control during the intervention period, and long-term follow-up data. These gaps make it difficult to isolate exercise effects from other lifestyle factors and to understand whether changes persist beyond the study period.

What This Means for You

Realistic expectations for weight loss. The average 2 kg weight loss from aerobic exercise alone is real but modest. This aligns with broader research showing that exercise typically contributes less to weight loss than dietary changes. If weight loss is your primary goal, combining aerobic training with dietary modifications will likely be more effective than aerobic exercise in isolation.

Fat loss appears more consistent than weight loss. The moderate certainty evidence for reductions in body fat percentage and fat mass suggests aerobic exercise reliably reduces adiposity even when total weight loss is small. This matters because fat loss independent of weight loss indicates you're potentially gaining or maintaining muscle while losing fat.

Waist circumference may be the most practical metric to track. The moderate certainty evidence for waist circumference reduction (2 cm average) is meaningful because abdominal fat is more metabolically active than fat in other regions. This measurement is also free and requires no equipment, making it practical for self-monitoring.

Dose matters less than you might think. The absence of a clear non-linear dose-response relationship suggests that doubling your exercise volume won't necessarily double your body composition benefits. The apparent plateau effect implies that consistency and adherence to a sustainable aerobic program may matter more than chasing maximum volume.

Age-related response differences are worth noting. If you're a younger postmenopausal woman (closer to age 50-55), you may expect slightly larger body composition changes from the same aerobic exercise compared to women further into postmenopause. This doesn't mean older women shouldn't exercise, but it explains why individual responses vary.

Consider pairing aerobic exercise with [resistance training](/habits/resistance-training). The imprecise lean body mass findings highlight a limitation of aerobic exercise alone. Resistance training preserves or increases lean mass while aerobic exercise may not substantially build it. A combined approach addresses both fat loss and muscle preservation.

Study Details

Sources