In middle-aged women, eight weeks of moderate aerobic exercise was linked to a decrease in muscle mass and fat-free mass, even though overall body weight and fat levels did not change, which may indicate limitations in how the measurements were taken or unmeasured factors like fluid balance or diet.

In young women with a BMI between 25 and 27, participating in supervised group aerobic exercise three times a week for 12 weeks leads to measurable decreases in body weight, waist size, and body fat, along with an increase in muscle mass.

Middle-aged women who engage in moderate aerobic exercise tend to spend more time in moderate-intensity physical activity and have higher overall energy expenditure per week, but their walking and high-intensity activity levels remain unchanged.

In simple terms, this means that doing resistance training with either medium or heavy weights leads to about the same amount of fat loss in young women who are new to exercise over 8 weeks. Both types of workouts can help you lose fat.

In young women with obesity, a four-week program of moderate aerobic and strength training is linked to an average gain of 3.61 kilograms of muscle, while those who did not exercise lost an average of 0.85 kilograms of muscle.

A 12-week supervised exercise program that burns about 10.5 megajoules per week leads to comparable decreases in body fat and fat mass in overweight and obese men and premenopausal women, with no meaningful difference between the sexes.