Exercise

At Rhodes University in Memphis, TN, Dr. Gerecke and team report that exercise may be neuroprotective and have shown that exercise reduces the loss of dopamine-producing neurons after MPTP exposure. MPTP is a neurotoxin that causes loss of the dopamine-producing neurons in the same brain region that degenerates in human Parkinson’s disease. Therefore, MPTP is used to generate an animal model for PD. Dr. Gerecke showed that three months of exercise provided complete protection against MPTP-induced neurotoxicity in mice. If running was limited to one to two months, or if the amount of running daily was decreased, the protective effects of exercise ended. In short, daily, sustained exercise was necessary for full protection.

Dr. Gerecke also found that three months of exercise induced changes in proteins related to energy regulation, cellular metabolism, cytoskeleton dynamics and intracellular signaling events. These changes might be responsible for the neuroprotection.

Other research findings include:

• Out of 14 studies on treadmill training, three show an immediate effect of increased walking speed, longer stride length and improved balance as early as after one treadmill session. Eleven longer-term trials demonstrated safety and positive benefits in gait speed, strike length and related quality of life even several weeks later.
• At the Cleveland Clinic, Dr. Alberts and team found that when people with PD pedaled on a stationary bike 30 percent faster than their preferred rate, they gained in aerobic fitness and showed improvement in motor function and coordination as well as manual dexterity. This improvement was retained for weeks after exercise stopped.
• Evidence in animal models with PD have shown that intensive exercise can alter the way the brain works and promote recovery.
• Mice models have shown that exercise improves that efficiency by modifying some of the areas of the brain where dopamine signals are received (ie, the substantia nigra and basal ganglia).

Research has shown that exercise can improve gait, balance, tremor, flexibility, grip strength and motor coordination. Exercise such as treadmill training and biking have all been shown to benefit, along with Tai Chi and yoga.

Studies have shown that:

• Engaging in any level of physical activity is beneficial for movement symptoms.
• For people with mild to moderate PD, targeted exercises can address specific symptoms. For example: aerobic exercise improves fitness, walking exercises assist in gait, and resistance training strengthens muscles.
• One study showed that twice-a-week tango dancing classes helped people with PD improve motor symptoms, balance and walking speed.
• Exercise may also improve cognition, depression and fatigue. Research is ongoing in these areas.
• People who exercise vigorously, for example running or cycling, have fewer changes in their brains caused by aging.

Many physicians and physical therapists believe that exercise improves mobility, thinking, memory and reduces the risk of falls. In avoiding complications from falls, you can prevent further injuries and emergency hospitalizations.

Neurologists within the Parkinson’s Foundation Center of Excellence network recommend that their patients with Parkinson’s follow a regimented exercise program, along with anyone who may be at a higher risk of developing Parkinson’s.

More and more researchers are dedicating studies to proving that exercise is an essential part of managing Parkinson’s. Ongoing exercise-related studies are also looking to discover therapies that will change the course of the disease. Through our research grants, the Parkinson’s Foundation supports research dedicated to better understanding how exercise can achieve the best quality of life for people with PD.

More research is needed to understand which aspects of exercise are most important, whether the benefits are long-lasting and whether drug and other therapies influence its effects. In studying the underlying molecular mechanisms, scientists may find new targets for drug therapies. In the meantime, intensive exercise helps people with PD walk and move better. Research is beginning to reveal how it reconditions the underlying brain circuits.

We know that in PD, neurons that produce the chemical transmitter dopamine are damaged and lost. There is a period of time between when the loss of neurons begins and when PD movement symptoms start to show. By the time most people are diagnosed, nearly 80 percent of their dopamine neurons are already gone.

During this period, the brain changes, compensating for the loss of dopamine neurons which occurs during the process of neurodegeneration. Scientists call this ability to change and compensate exercise-dependent neuroplasticity . This same process occurs throughout life in response to experience. As children learn motor skills, for example, their brain cells make new connections. This process continues through adulthood.

Exercise may affect the brain by driving this compensation, or plasticity. People with PD who exercise regularly can move more normally than those who do not. We believe that exercise may be contributing to neuroplasticity — helping the brain maintain old connections, form new ones and restore lost ones. This may outweigh the effects of neurodegeneration.

What happens in the brain to produce these benefits? A study conducted by Beth Fisher and her team at the University of Southern California found that on a day-to-day basis, people with PD who exercised moved more normally than those who did not.

The study also found that in looking at mice that had exercised under conditions parallel to a human treadmill:

• Exercising did not affect the amount of dopamine in the brain, but the mice that exercised the brain cells were using dopamine more efficiently and their dopamine signals lasted longer.
• Exercise improves efficiency by modifying the areas of the brain where dopamine signals are received — the substantia nigra and basal ganglia.

Based on these findings, the research team believes exercise may help the brain maintain old connections, form new ones and restore lost ones. In certain situations, the neuroplasticity created from exercise in people with PD may outweigh the effects of neurodegeneration.