Exercise as it relates to Disease/The Benefits of Exercise for People with HIV

What is HIV?
Human Immunodeficiency Virus (HIV) interacts with the human immune system through the binding of HIV to the CD4 molecules on T-cells, monocytes and macrophages, resulting in diminished function of the immune system. The two strains of HIV are HIV-1, the most common form, and HIV-2 that is rare outside of West Africa. HIV-2 differs in that it is less likely to produce disease, is less efficient in its transmission, and results in slower disease progression. HIV can infect anyone as shown by research subjects who differ in areas such as gender, race, nationality, age and sexuality. Acquired Immunodeficiency Syndrome (AIDS), the final stage of HIV, results from infection of certain elements of the human immune system leading to an increased likelihood of developing opportunistic infections and AIDS related diseases.

Prevalence of HIV
In 2012, approximately 35.5 million people worldwide were living with HIV. In Australia in 2012, an estimated 25 708 people were diagnosed as living with HIV, which is approximately 5.4 per 100 000 people.

Signs and Symptoms of HIV
Signs and symptoms may include:
 * Fever
 * Weight loss
 * Muscle wasting and weakness
 * Impaired functional work capacity
 * Depression
 * Decreased quality of life

Treatment of HIV
Thus far there is no cure for HIV just methods of slowing the progression, which includes highly active antiretroviral therapy (HAART) or steroid and growth hormone administration or alternative methods by the in activating enzymes like proteases.reverse transcriptase such as exercise.

HIV and Exercise
In a HIV population exercise is used therapeutically to minimise the debilitating effects and to slow the progression of the disease. The impact of prolonged, high intensity or overtraining has been shown to lead to more severe infections and negative impacts on immune function in humans therefore many physicians recommend that their patients with HIV avoid physical exertion despite evidence that moderate intensity exercise minimises the symptoms of HIV infection and positively affects immune measures. Regular exercise results in positive impacts on physical and psychological health.

Benefits of Exercise
The benefits will vary depending on the stage of disease but the benefits of exercise that can be achieved without compromising the immune system include benefits of both aerobic and resistance training.

Aerobic
Some benefits achieved through aerobic exercise include
 * Improved body composition
 * Increased functional capacity
 * Improved immune function and measures
 * Improved quality of life
 * Reduced depression

Resistance
Some benefits of resistance training include
 * Increased muscular strength
 * Improved body composition
 * Muscular hypertrophy
 * Increased muscular endurance

Recommendations
Prior to participating in exercise it is recommended that all patients obtain medical clearance from their physicians. Further, it is recommended that training sessions be monitored by an appropriately trained professional until the patient can tolerate the prescribed workload. An exercise program should be tailored to suit each individual taking into consideration medications, stage of disease progression, symptoms, and functional capacity. Recommended exercise guidelines for individuals with HIV are presented below.

Aerobic

 * 3-5 sessions per week of 20–60 minutes at 50-85% of heart rate max or 45-85% of VO2 max

Resistance

 * 3 times per week using 3 sets of 8 repetitions with resistance based on 1-repetition maximums
 * Progressive model: sets and repetitions remain constant and intensity increases

Combined

 * Progress when tolerated to 3-5 session per week of 20–60 minutes of continuous aerobic exercise at a moderate intensity of 11-14 on Borgs' Rating of Perceived Exertion Scale, 50-85% of peak heart rate or 45-85% of VO2 max. Complete 4–6 weeks of aerobic training prior to beginning resistance exercise at moderate intensity completing 8-12 repetitions.