Exercise as it relates to Disease/Exercise Prescription for the control of Metabolic Syndrome
Metabolic Syndrome (MetS) or Syndrome X affects up to 1 in 3 Australians, being an interrelation of many distinct metabolic irregularities, especially the associated increase in Type 2 Diabetes and Cardiovascular Disease. There are a number of interventions/treatments, with exercise interventions reducing prevalence and negative outcomes.
Australian prevalence (hard to define due to it’s varying symptoms and definitions) is ~ 29-33%, however numerous sources show increases in the prevalence of the overweight and obese (64.1% of women, 74.1% of men) and an increase in the diagnosis of Type 2 Diabetes. This translates directly into a high (increasing) prevalence of MetS, greater in men than women, steadily increasing from the age of 25, and progressively increasing as waist circumference increases.
Causes and SymptomsEdit
The disease state is also known as Insulin Resistance Syndrome, Metabolic Syndrome X, or simply Syndrome X due to the interrelation of the many key physiological factors, which can be seen in the following table:
|Defining Physiological Features||Range (highest definitions of the range included in brackets)|
|↑ Abdominal Obesity (Waist Circumference)
↑ Triglyceride Level
↑ Blood Pressure
↑ Urinary Albumin Excretion Ratio
* or ↑ Albumin:Creatinine ratio
> 94 (102)cm
> 80 (88) cm
≥ 1.7 (2.0)mMol/L (159 mg/dL)
< 0.9 (1.04) mMol/L
< 1.0 (1.30) mMol/L
≥ 130 (140) (Systolic)/≥ 85 (90)(Diastolic)mmHg
≥ 5.6 (6.1) mMol/L
≥ 30 mg/g
Focus of Intervention/TreatmentEdit
The primary focus for the treatment/prevention of MetS is manipulation of lifestyle  (such as a change in diet, weight loss, quitting smoking, reduction in stress levels, pharmaceutical use and potentially surgery) and exercise levels; the primary concentration being treatment of obesity (due to the high correlation/direct relationship MetS has to central/visceral obesity), seconded by improvement of Insulin resistance.
Up to 20% of Australians are classed as physically inactive, or insufficiently active (36%) and low aerobic exercise capacity appears to be the strongest predictor of mortality from MetS. Regular exercise leading to weight loss is key for positively altering insulin resistance, and glucose response, but also for influencing a number of other MetS features.
Aerobic exercise is optimal, due to its high correlation to a reduction in abdominal (or visceral) adiposity, and as aerobic physiological adaptations are highly beneficial specifically:
- As an anti-inflammatory reducing metabolic stress.
- ↓ In inflammatory cytokines (CRP, TNF-α, Adhesion molecules etc) via reductions in visceral fat/initiation of anti-inflammatory environment.
- ↓ Blood pressure (as much as 11mmHg systolic, 9mmHg Diastolic )
- ↓ Cardiovascular disease risk.
- ↓ Blood Glucose levels
- ↓ Psychosocial stress
- ↓ Plasma triglycerides 
- ↓ Mean Arterial Pressure (MAP) 
- ↑ Insulin sensitivity in muscle cells 
- ↑ High Density Lipoprotein Cholesterol (↓LDL)
- ↑ Release of Adrenalin and Cortisol and ↓ in Pro-inflammatory monocytes 
Type of aerobic activity varies, American College of Sports Medicine (ACSM)  suggesting that sessions of continuous sub-maximal activity are best for controlling MetS, but other sources  show that greater response is seen when a frequent change in intensity was introduced i.e. aerobic interval training.
Abundant new evidence recommends resistance training should also be considered due to:
- Primarily its impact on skeletal muscle (and its role in the metabolism of triglycerides and glucose) 
- general ↓ in fat mass,
- ↓ in systolic blood pressure,
- Improvement in glycaemic control,
- ↑ Insulin sensitivity (same mechanism as aerobic exercise).
Resistance training has much less of an effect on total cholesterol levels, HDL, LDL, triglyceride levels, and Diastolic BP. Increases in muscular strength may be imperative in the conservation of lean body mass (particular in the elderly) increasing the general activity level, and adding variety to exercise programs (facilitating adherence).
All programs should be tailored to individual needs and capabilities, based on age, fitness level, and any considerable risk factors; see the following #Precautions and Further Resources. Program for continued, consistent energy expenditure. Whilst weight loss/<adiposity seems to be greater when observing aerobic capacity the positives of resistance training must be considered thus a combination may be best. Select a mode of exercise that:
- Uses large muscles/muscle groups (vary between upper and lower body modalities).
- Varies between non-weight bearing and weight bearing activities
- Can be graded to overload the cardio-respiratory system.
Frequency: 2 or more days per week (1-2 sets of 8-12 reps, with an intensity >60% of an individuals 1RM with 8-10 exercises per session). Aerobic exercise above 180 min/week has a “dose-response” effect i.e. ↑ Frequency = ↑ Physiological response. Resistance training is less dose-dependent and ↑ Frequency will not necessarily ↑ response. Three sessions ≥60min/week with an intensity ≥75% maximum heart rate yields best results for aerobic exercise.
Exercise should be predominantly aerobic based to maximise CV adaptations with additional resistance-training components for strength and functional capacity development. Ideally a combination of strength and aerobic, especially aerobic interspersed with regular increases to high intensity (interval training) for a minimum of 12 weeks.
Precautions and Further ResourcesEdit
Before engaging in any exercise or exercise prescription (especially "at risk" populations/individuals), it is recommended to get checked by a health professional, as well as undertaking specific Pre-Exercise screening tools (such as the ESSA Screening system). ESSA Screening Tool and Information
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