If you're looking to trim some inches around your stomach but hate cardio, researchers from the Harvard School of Public Health have a Christmas gift for you.

The researchers studied 10,500 healthy men aged 40 and older, according to a news release. They analyzed the physical activity, waist circumference and body weight of the men over a 12-year period. 

During the study, men who weight trained for 20 minutes a day saw a larger waistline decrease than men who did aerobic training for 20 minutes a day. 

"Because aging is associated with sarcopenia, the loss of skeletal muscle mass, relying on body weight alone is insufficient for the study of healthy aging," lead author Rania Mekary, a researcher in HSPH's Department of Nutrition, said in a news release. "Measuring waist circumference is a better indicator of healthy body composition among older adults. Engaging in resistance training or, ideally, combining it with aerobic exercise, could help older adults lessen abdominal fat while increasing or preserving muscle mass." 

Similar weight loss studies have been conducted in the past - mostly focusing on a specific population, such as overweight people or those with type 2 diabetics, over the course of a shorter duration of time. The Harvard School of Public Health study used a sample of healthy men with a wide range of body mass indexes over a longer period of time, reported the news release.

"This study underscores the importance of weight training in reducing abdominal obesity, especially among the elderly," Frank Hu, professor of nutrition and epidemiology at HSPH and senior author of the study, said in the news release. "To maintain a healthy weight and waistline, it is critical to incorporate weight training with aerobic exercise."  

The study was published on Dec. 22 in Obesity.