Strength training and waist circumference change in men
Waist circumference (WC) is measurement taken midway between the lowest rib and the hip bone and is a marker of abdominal obesity. Excess fat around the abdominal region increases the risk of cardiovascular disease,diabetes and many other chronic diseases.
Studies have shown that inactive individuals are at greater risk for chronic diseases than those who are regularly active and have a lower WC. Most studies have examined the effects of moderate-to-vigorous-intensity aerobic activity (MVPA) (brisk walking or jogging), however few studies have examined the effects of strength training (ST) on WC, or concurrent MVPA-Strength training.
The aim of this study was to examine the long-term effects of MVPA, ST and changes in these behaviours on WC.
This U.S-based longitudinal study was conducted at the prestigious Harvard School of Public Health in Boston. Data were used from the Health Professionals Follow-up Study, which involves 10,500 men aged 40-75 years. In 1996 and again in 2008, participants self-reported their physical activity (MVPA and ST), WC and other potential confounding factors (e.g., diet, smoking, alcohol consumption and TV viewing).
Strength training levels were divided into 4 categories: (1) None, (2) >0-10, (3) 10-25, and (4) >25 minutes/day.
The main outcome of the study was change in WC over a 12-year period (1996-2008).
Over 12 years, on average participants WC increased by 6.61cm. Overall, only 1.8% of the sample were in the highest Strength training group (>25 minutes/day). In contrast, most (71.5%) reported no ST during this time period.
When adjusted for MVPA, TV viewing and other factors (age, diet etc.), compared to those who did no Strength training, men who did >25 minutes/day had -1.39cm lower WC.
There was a trend for a dose-response relationship between minutes per day spent in Strength training.
Strength training build muscle mass, which increases your total daily energy expenditure. Also, Strength training results in greater levels of excess post-exercise oxygen consumption, which is necessary for the muscles to repair and regenerate after exercise
This study showed that over a 12-year period, resistance training was more beneficial in preventing an increase in waist circumference when compared to aerobic exercise.
This study provides further evidence of the health benefits of including Strength training into any exercise program.
Authors: Mekary RA, Grøntved A, Despres J-P, De Moura LP, Asgarzadeh M, Willett WC, Rimm EB, Giovannucci E, Hu FB
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