Aerobic exercise (such as brisk walking and swimming) has long been recommended as part of a ‘healthy’ lifestyle, particularly with regard to heart and ‘cardiovascular’ health and weight control. However, in recent times there has been a little more focus on the role of ‘resistance’ exercise (such as weight-training) as a means to improve health, wellbeing and weight. With this in mind, I was interested to a read a study published this month in the American Journal of Clinical Nutrition which assessed the effects of weight training in a group of overweight women .
This American study, conducted in women aged 25-44, assigned participants to either a two-year programme of weight training or a ‘control’ group who received a leaflet geared to encouraging aerobic exercise. Those in the weight training group went participated in two hour-long weight training sessions a week for the first year, after which the session time was cut to 45 minutes. All participants were instructed not to make any dietary changes.
The participants were assessed for a number of body measurements including body mass index (weight in kg divided by the square of height in metres), body fat percentage and amount of intra-abdominal fat (fat within the abdomen which is linked with a increased risk of chronic disease including diabetes).
By the end of the 2-year programme, there was no significant change in BMI between the two groups. However, there was a statistically significant difference in body fat percentage: while the control groups’ body fat was essentially unchanged, the resistance exercisers saw an average reduction in body fat percentage of about 3.5 per cent. The exercising group fared better in terms of intra-abdominal fat too.
The authors of this study conclude that their study: �suggests that strength training is an efficacious intervention for preventing percentage body fat increases and attenuating intraabdominal fat increases in overweight and obese premenopausal women.�
I suppose it will not come as a particular surprise that weight training compared to doing, essentially, nothing at all, helps reduce fat in the body. The energy expended during the exercise itself may help here. In addition, though, the increased energy demands of bigger and/or stronger muscles may help maintain the metabolism and enhance fat loss ‘for free’.
Some women may be averse to weight training, perhaps on account of the fact that it has a reputation for ‘bulking up’ the body. Interestingly, this study found that while the women who participated in the programme ended up stronger, they did not appear to gain any appreciable muscle mass. Certainly, the results of this study suggest that at moderate levels of weight-training, bulking up is not an issue.
Of course another reason for considering weight training is that the enhanced strength it brings may help to preserve mobility as we age. The fact of the matter is that some elderly individuals lack the muscle-power to, for instance, get out of a chair or carry bags of shopping. Resistance training may therefore help to preserve our health and quality of our lives into old age.
Schmitz KH, et al. Strength training and adiposity in premenopausal women: Strong, Healthy, and Empowered study American Journal of Clinical Nutrition 2007;86(3):566-572