Even if you walk daily, you might control your weight better by practicing weightlifting at least twice per week, according to new research. In a study published in the journal Obesity, people who did the recommended amount of aerobic exercise (150 minutes or more per week of an activity like walking) were 28% less likely to be obese. Those who did the recommended amount of muscle-strengthening exercise (two or more sessions of weightlifting per week) were 30% less likely to be obese. But people who did the recommended amount of both forms of exercise had the lowest odds of obesity — they were 50% less likely to be obese.
The Australian study was the first to analyze associations between aerobic exercise, muscle-strengthening exercise and obesity in such a large sample of adults (1.7 million people). “Up until 2008, physical activity guidelines [including World Health Organization guidelines and the Physical Activity Guidelines for Americans] exclusively recommended aerobic exercise — it is only within the last decade that muscle-strengthening exercise has been included in physical activity guidelines,” says study author Jason Bennie, PhD, a senior research fellow at the University of Southern Queensland in Australia.
“I believe resistance training and aerobic exercise work at different mechanisms at the muscular cellular level, like taking two different medications,” says Dr. Tim Church, MPH, PhD, professor of preventive medicine at Pennington Biomedical Research Center at Louisiana State University. You may build more muscle from the combined exercise regimen, which could be a contributing factor.
“There is some clinical evidence that doing both muscle-strengthening and aerobic exercise may result in an increased muscle mass, which leads to increased metabolic rate and/or total energy expenditure,” Bennie says.
Another study from 2010 found the combination of aerobic exercise and muscle-strengthening exercise helped people with diabetes improve their blood sugar levels.
People who walked on a treadmill for roughly 110 minutes each week and did muscle-strengthening exercises with weights twice a week for about 15 minutes each were able to lose about 3.7 pounds and lower their A1C numbers (which measures someone’s average blood sugar levels over the previous 3-month period) by 0.3 to 0.4 over a 9-month period. When people only did one type of exercise (aerobic or muscle-strengthening), the impact on A1C wasn’t as great.
What’s more, “clinical exercise studies have identified that, compared with one mode alone, combining aerobic or muscle-strengthening exercise has unique cardiometabolic health benefits,” Bennie says. “These include more favorable associations with cholesterol and insulin levels.”
Like any exercise, it’s a good idea to build up gradually. “Start with bodyweight exercises, such as pushups, squats, situps and lunges. Then progress to weight machines [or] free weights,” recommends Bennie.
There’s no set length of time that’s ideal for muscle-strengthening exercises, but it’s helpful to focus on several (but not all) muscle groups during each session — such as the arms, legs, chest, shoulders, back and trunk. Aim to do 2–4 sets of 10–12 repetitions. This may take 15–20 minutes.
When in doubt, it’s always a good idea to work with a professional trainer who can develop an individualized plan.
Adding weight training to your exercise regimen twice weekly may help you maintain a healthy weight, better control your blood-sugar levels and experience other positive health benefits.
“You lose [about] 1% of strength/muscle mass per year from age 40–50 on,” Church says. “Muscle and strength are critical to healthy aging. [So] everyone stands to benefit from weightlifting.”
Still, more research is needed to see if the combination of walking and weightlifting is effective for weight loss. However, “our data clearly show an inverse association between reduced body mass index and combined moderate to vigorous physical activity [and] muscle‐strengthening exercise,” says Bennie.