The effect of exercise on the cardiovascular risk factors constituting the metabolic syndrome: a meta-analysis of controlled trials.

"No potential conflicts of interest directly relevant to this content of this article were reported. Véronique A. Cornelissen is supported as a Postdoctoral Fellow by Research Foundation Flanders (F.W.O.). Prof. Luc Vanhees is the holder of the faculty chair ‘Lifestyle and Health’ at the University of Applied Sciences, Utrecht, the Netherlands; Nele Pattyn is a doctoral researcher at the KU Leuven, Department of Rehabilitation Sciences; Saeed R. Toghi Eshghi was a Master’s student at KU Leuven, at the time of the preparation of this article."

"Although the observed effect on each of the individual risk factors might seem small, when we combine all the effect sizes, that is a BP reduction to a mean of 131/82 mmHg, a decrease in WC to an average of 101 cm and for plasma glucose and triglycerides to a mean of 5.67 and 2.0 mmol/L, respectively and an increase of HDL-C to 1.1 mmol/L, a large number of patients would probably no longer be classified as having the MetS. Earlier, Katzmarzyk et al. [] showed that 30.5% of patients (mean age 44.7 years) with the MetS at baseline, were no longer classified as having the MetS after a 20-week supervised dynamic endurance training programme. This reduction was mostly due to an improvement in triglycerides (43%), BP (38%) and WC (28%) whereas beneficial effects on HDL-C and plasma glucose were seen in fewer patients (16 and 9%, respectively). Similarly, Anderssen et al. [] reported that 23.5% of 34 patients no longer had the MetS after an exercise intervention of 1 year. The only study included in this meta-analysis reporting on the number of patients with the MetS showed similar decreases with a 37.5% (from 8/8 to 5/8) and a 45% decrease (from 11/11 to 6/11) following 16 weeks of continuous and interval training, respectively []. Although it is difficult to quantify exactly the overall risk reduction associated with all observed changes, these results are compatible with an overall improvement of cardiovascular risk. Moreover, the results of this meta-analysis study are supported by studies that have examined the cross-sectional relationship between physical activity and the MetS. For example, in 1298 healthy police employees of the Utrecht Police Lifestyle Intervention Fitness and Training (UPLIFT) study, average physical activity intensity, average time spent at physical activity, physical activity volume and physical fitness, were each associated with reduced odds of the MetS []. Taken together, the results of these studies, and those from the present meta-analysis, reinforce the notion that physical activity is an important treatment option for the MetS, as stated in Katzmarzyk et al. []."