Aerobic Exercises the Better Bet

While it is important to do weightlifting if you want to maintain muscle tone, if your goal is to lose fat then cardio exercises is far better than resistance training, researchers say. And gets far better results.

The study in question was conducted by North Carolina researchers and is the largest randomized trial ever done to directly compare changes in body composition induced by comparable amounts of time spent doing aerobic and resistant training, or both in combination, among previously inactive overweight or obese non-diabetic adults.

So how did they do it?

A total of 234 previously sedentary overweight or obese males and females, ages 18 to 70 years of age, were enrolled in one of three eight-month supervised protocols: aerobic training (AT), resistance training (RT), or a combination (AT/RT). Of the total 234 overweight / obese people, 119 participants completed the trials and had complete data for the variables of interest for the study. The remaining 115 people gave up part way through.

The people assigned to aerobic exercises did so vigorously, at about 70-85 percent of their maximum heart rate. They exercised approx. 45 minutes three days per week throughout the study period.

The people assigned to weight lifting also exercised three days a week for a period of approx. 45 minutes, completing three sets of 8-12 reps on eight different resistance machines that targeted all major muscle groups. The amount of resistance was increased throughout the study to maintain a steady level of challenge as the participants gained strength.

The people who were assigned to AT/RT performed all the exercises assigned to both AT and RT groups, for a total of approx. 90 minutes.

At the end of the study each person was assessed for weight, body composition, waist circumference, cardiopulmonary fitness and strength compared to their baseline.

The researchers found that the groups assigned to aerobic exercises and aerobic plus resistance training lost significantly more weight than those that did resistance training only. In fact, some of those who did resistance training only actually gained weight due to an increase in lean body mass and didn't lose any fat weight.

Fat mass and waist circumference significantly decreased in the AT and AT/RT groups, but were not altered in RT. However, measures of lean body mass significantly increased in RT and AT/RT, but not in AT. The findings show that aerobic exercise is more effective in reducing fat.

Lean muscle mass increased with both RT and AT/RT, but not AT. Having the benefit to of both modes of exercise allowed AT/RT to decrease body fat percent significantly more than either AT or RT due to decreased fat mass combined with increased lean body mass.

Given the results it is clear that weight training isn't very effective at reducing fat. Cardio exercises is the clear winner when it comes to fat reduction, although a mixture of both is certainly advised if people want to both cut fat and gain muscle.

"If increasing muscle mass and strength is a goal, then resistance training is required. However, the majority of Americans could experience health benefits due to weight and fat loss. The best option in that case, given limited time for exercise, is to focus on aerobic training. When you lose fat, it is likely you are losing visceral fat, which is known to be associated with cardiovascular and other health benefits," says the lead author of the study, Leslie H. Willis, an exercise physiologist at Duke University Medical Center.

As a personal trainer in Toronto I must admit that there are some people in this industry who are pushing the idea that you can achieve all the results cardio can using weight lifting... but they don't have the science to support their claims, and it is, frankly, putting all of your eggs in one basket.

The clear solution is a mixture of both cardio and weight lifting, modified to a person's goals and needs. Because if you're only lifting weights and wondering why you aren't losing any fat, the answer becomes pretty obvious - Its time to do more cardio.