Exercise Benefits Patients with Parkinson’s Disease

Abstract & Commentary

By Jeffrey Gross, MD, Clinical Associate Professor of Rehabilitation Medicine, NYU School of Medicine, Adjunct Clinical Assistant Professor of Rehabilitation Medicine, Weill Cornell Medical College. Dr. Gross reports no financial relationships relevant to this field of study. The article originally appeared in the May 2013 issue of Neurology Alert.

Synopsis: Exercise, both aerobic as well as stretching and strengthening, improves motor function and gait in patients with Parkinson’s disease.

Source: Shulman LM, et al. Randomized clinical trial of 3 types of physical exercise for patients with Parkinson disease. JAMA Neurol 2013;70:183-190.

There is growing interest in the use of exercise training to improve mobility and function in patients with early Parkinson’s disease (PD). A recent literature review showed that there were 75 clinical trials of physical training for PD.1 The results of these trials have been promising. However, the majority of the studies were limited by methodological flaws.

Shulman et al performed a prospective, randomized, single-blind, parallel-group clinical trial of efficacy of three types of physical exercise for PD: 1) higher-intensity treadmill (HITM), 2) lower-intensity treadmill (LITM), and 3) stretching and resistance (SR). The primary objective of this clinical trial was to compare the efficacy of these three types of physical exercise to improve gait, fitness, and strength in patients with PD. The additional objectives were to study the efficacy of exercise to reduce disability and nonmotor symptoms in PD. The criteria for eligibility included a diagnosis of PD with no atypical signs or exposure to dopamine-blocking drugs, a Hoehn and Yahr stage of 1 to 3, the presence of mild-to-moderate gait or balance impairment, an age of 40 years or older, and no significant dementia. Exclusion criteria were unstable medical or psychiatric comorbidities, orthopedic conditions restricting exercise, or active participation in a regular exercise program before enrollment.

A screening treadmill exercise test was used to determine cardiopulmonary safety and neuromotor capacity to participate. The total duration of the study was 4 months. Initial evaluations included medical history and physical and neurologic examinations. Baseline and post-training assessments were performed by physicians and staff blinded to participants’ treatment group. All evaluations were undertaken while the participants were in the “on” periods from medications, or within 3 hours of medication dosing.

Pre- and post-training maximum oxygen ventilation (VO2 max) was assessed during treadmill exercise with the endpoint being voluntary exhaustion. Gait assessments were performed before and after training. The 6-minute walk (6MW) was the primary motor outcome measure. Participants were instructed to cover as much distance as possible in 6 minutes, turning every 30 meters. Other gait measures were two 10-meter walks (self-selected and fastest comfortable pace) and a 15-meter fast gait. Muscle strength was assessed with a 1-repetition maximum strength test performed before and after training in all study groups for leg press and leg extension. Strength in each leg was tested separately on isotonic weight machines. Disability and physical activity assessments were tabulated. Nonmotor symptom assessments also were performed before and after training.

Sixty-seven participants in the study were randomized into three groups that trained three times per week for 3 months under the direct supervision of exercise physiologists. Vital signs were monitored. All participants wore a non-weightbearing harness to eliminate the risk of falls. The HITM group exercised up to 30 minutes at a speed and incline that eventually resulted in a heart rate of 70-80% of their maximum (220 minus age). The LITM group walked at a comfortable pace for up to 50 minutes. The incline and speed remained constant. Their heart rate remained in the range of 40-50% of their calculated maximum. The SR group did two sets of 10 reps on leg extension, leg press, and leg curl machines. Weight was increased as tolerated. Stretching was performed as well.

There were no serious adverse events during the study. The results revealed improvements in all three groups for the 6MW. The greatest gains were made by the LITM group (12%), followed by the SR (9%) and the HITM (6%) groups, but the differences were not statistically significant between groups. The LITM group also made significant gains in the other gait measurements. VO2 max increased in only the HITM and LITM groups. Lower extremity muscle strength only increased in the SR group. No significant changes were noted in disease severity, disability, or nonmotor symptoms in any of the groups.

Commentary

The above results confirm the value of a regular exercise program for PD patients in the early stage of disease. Low-intensity treadmill exercise was proven to be safe, well tolerated, and beneficial in improving function and cardiovascular fitness. Resistance exercise leads to increased strength, as would be expected. A combination of these interventions seems warranted in all early PD patients who are medically well and able to participate. Although the exercise programs did not result in improvements in disability or quality of life, these variables did not deteriorate during the study either. This reflects the study’s main limitation — there was no non-exercise control group.

Reference

1. Mehrholz J, et al. Treadmill training for patients with Parkinson’s disease. Cochrane Database Syst Rev 2010; (1):CD007830.