In a recent study, researchers sought to determine whether the U.S. Surgeon General Office's recommendation of moderate intensity exercise four or more times per week for at least 30 minutes per occasion was sufficient to facilitate body fat loss.
Ninety men and women were instructed to voluntarily exercise for 30 minutes four times weekly for 8 weeks. Participants were given two options, either continuous steady state cardiovascular training at 70% of HRmax, or circuit training for 30 minutes achieving similar intensity. Body composition was evaluated using air displacement plethysmography, familiar to most as a BodPod.
After 8 weeks the participants were categorized into controls, and by number of days exercised per week over the course of the study: less than 2 times per week, 2 to 3 times per week and 4 or more times per week. All three exercise groups lost body fat on average, however, only those who exercised 4 or more times per week achieved significant body fat loss during the 8 week study, approximately 13 lbs.
Although diet was not controlled for during this study, the findings underscore the importance of frequency of exercise for fat loss. The majority of Personal Training clients exercise with their Trainer 2 or 3 times per week. It is important that clients are encouraged to train additionally on their own to accumulate the desirable frequency.
Willis, F.B. et al (2009) Frequency of Exercise for Body Fat Los: A Controlled, Cohort Study. Journal of Strength & Conditioning Research 23 (8): 2377.