Dyslipidemia

Dyslipidemia refers to abnormal blood lipid and lipoprotein concentrations. Dyslipidemia exists when there are elevations in low-density lipoprotein cholesterol (LDL) or triglyceride concentrations or when there is a reduction in high-density lipoprotein cholesterol (HDL). The table below provides the National Cholesterol Education Program (NCEP) blood lipid and lipoprotein classification scheme. Severe forms of dyslipidemia are usually caused by genetic defects in cholesterol metabolism, but marked dyslipidemia can be secondary or caused by another systemic disease. Substantial increases in LDL are often caused by genetic defects related to the hepatic LDL receptor activity but can also be produced by hypothyroidism and the nephritic syndrome. Similarly, some of the highest triglyceride concentrations are produced by insulin resistance and/or DM and marked reductions in HDL are caused by the use of oral anabolic steroids. Dyslipidemia is a major modifiable cause of CVD.

Improvements in cholesterol awareness and more effective treatments primarily using statins or hydroxymethylglutaryl-CoA (HMG-CoA) reductase inhibitors are responsible  for the decline in the prevalence of elevated blood cholesterol levels in recent years. These improvements have contributed to a 30% decline in CVD. Recent clinical trials indicate the added value of cholesterol lowering therapy in high risk individuals, individuals with DM, and older individuals with a treatment goal to lower baseline LDL concentrations by 30%-40%. Current detection, evaluation, and treatment guidelines for dyslipidemia are available in the NCEP Adult Treatment Panel (ATP) III report. The NCEP ATP III report recognizes the importance of lifestyle modification in the treatment of dyslipidemia. These recommendations include increased physical activity and weight reduction if warranted, but expect for the hypertriglyceridemia associated with insulin resistance, most hyperlipidemia requires medication therapy in addition to diet and exercise modification. Nevertheless, exercise is valued for controlling other CVD risk factors and should be a primary component to leading a healthy lifestyle. The ACSM makes the following recommendations regarding exercise testing and training of individuals with dyslipidemia.

Guidelines for Exercise Testing

The following bullets are the ACSM's guidelines for exercise testing for individuals with dylipidemia:

• Individuals should be screened and risk classified prior to exercise testing.
• Caution should be used when testing individuals with dyslipidemia because underlying CVD may be present
• Standard exercise testing methods and protocols are appropriate for use with individuals with dyslipidemia cleared for exercise testing. Special consideration should be given to the presence of other chronic diseases and health conditions that may require modifications to standard exercise testing protocols and modalities. 

Exercise Prescription for Dyslipidemia

The FITT of exercise prescription for individuals with dyslipidemia without comorbidities is very similar to the prescription for healthy adults. The only major difference between the FITT principle for individuals with dyslipidemia compared to healthy adults is that healthy weight maintenance should be emphasized. Consequently, aerobic exercise becomes the foundation of the exercise prescription. Resistance and flexibility exercises thus become secondary to an aerobic training program. This is because these modes of exercise do not substantially contribute to the overall caloric expenditure goals that appear to be beneficial for improvements in blood lipid and lipoprotein concentrations.

Here is the ACSM FITT recommendations for individuals with dyslipidemia:

Aerobic Exercise

Frequency: Greater than or equal to five times a week to maximize caloric expenditure

Intensity: 40% - 70% of resting VO2 or Heart Rate Reserve

Time: 30-60 minutes per day. However, to promote or maintain weight loss 50-60 minutes of daily exercise is recommended. Performance of intermittent exercise of at least 10 minutes in duration to accumulate these duration recommendations can serve as an effective alternative to continuous exercise.

Type: The primary mode should be aerobic physical activities that involve larger muscle groups. As  part of a balanced exercise program, resistance training and flexibility exercise should be incorporated. Individuals with dyslipidemia without comorbidities may follow the resistance training and flexibility guidelines for healthy adults.