Prevention of the metabolic syndrome and treatment of its main characteristics 
are now considered of utmost importance in order to combat the epidemic of type 
2 diabetes mellitus and to reduce the increased risk of cardiovascular disease 
and all-cause mortality. Insulin resistance/hyperinsulinaemia are consistently 
linked with a clustering of multiple clinical and subclinical metabolic risk 
factors. It is now widely recognised that obesity (especially abdominal fat 
accumulation), hyperglycaemia, dyslipidaemia and hypertension are common 
metabolic traits that, concurrently, constitute the distinctive insulin 
resistance or metabolic syndrome. Cross-sectional and prospective data provide 
an emerging picture of associations of both physical activity habits and 
cardiorespiratory fitness with the metabolic syndrome. The metabolic syndrome, 
is a disorder that requires aggressive multi-factorial intervention. Recent 
treatment guidelines have emphasised the clinical utility of diagnosis and an 
important treatment role for 'therapeutic lifestyle change', incorporating 
moderate physical activity. Several previous narrative reviews have considered 
exercise training as an effective treatment for insulin resistance and other 
components of the syndrome. However, the evidence cited has been less consistent 
for exercise training effects on several metabolic syndrome variables, unless 
combined with appropriate dietary modifications to achieve weight loss. Recently 
published randomised controlled trial data concerning the effects of exercise 
training on separate metabolic syndrome traits are evaluated within this review. 
Novel systematic review and meta-analysis evidence is presented indicating that 
supervised, long-term, moderate to moderately vigorous intensity exercise 
training, in the absence of therapeutic weight loss, improves the dyslipidaemic 
profile by raising high density lipoprotein-cholesterol and lowering 
triglycerides in overweight and obese adults with characteristics of the 
metabolic syndrome. Lifestyle interventions, including exercise and 
dietary-induced weight loss may improve insulin resistance and glucose tolerance 
in obesity states and are highly effective in preventing or delaying the onset 
of type 2 diabetes in individuals with impaired glucose regulation. Randomised 
controlled trial evidence also indicates that exercise training decreases blood 
pressure in overweight/obese individuals with high normal blood pressure and 
hypertension. These evidence-based findings continue to support recommendations 
that supervised or partially supervised exercise training is an important 
initial adjunctive step in the treatment of individuals with the metabolic 
syndrome. Exercise training should be considered an essential part of 
'therapeutic lifestyle change' and may concurrently improve insulin resistance 
and the entire cluster of metabolic risk factors.