Interval training reversed Parkinson's disease
A new experiment involving patients with Parkinson's disease has shown that high-intensity interval training can not only slow the neurodegeneration that accompanies this pathology, but also reverse it.
A key factor in the development of Parkinson's disease is thought to be the misfolding of the protein alpha-synuclein, present in human cells. As it accumulates, this misshapen protein disrupts the functioning of neurons and causes their death. Dopamine-producing cells, located in the area at the base of the brain called the substantia nigra, are most severely affected. As they die off, motor symptoms such as tremors and slowed movement appear.
Because of the gradual progression of the disease, patients usually have more than half of their dopamine-producing neurons dead by the time they are diagnosed. The most common treatment option, taking dopamine replacement drugs, relieves symptoms but does not protect against further neurodegeneration. In addition, long-term use of such drugs can lead to unwanted side effects in the form of uncontrolled excessive movements.
Although doctors have not yet found a way to cure Parkinson's disease, exercise plays an important role in therapy. In two previous clinical trials, researchers found that high-intensity exercise three times a week for six months correlated with a reduction in motor symptoms in people with Parkinsonism.
Experts from the Yale School of Medicine (USA) went a step further. In a new study published in the journal npj Parkinson's Disease, they tracked how interval training affected the patients' brains using positron emission tomography (PET) and neuromelanin-sensitive MRI scans.
Thirteen volunteers were initially recruited for the experiment, but after the trial period, three of them dropped out for various reasons. This left ten participants: six men and four women between the ages of 59 and 69. They had been diagnosed with Parkinson's disease less than four years ago, and had not yet lost all of their dopamine-producing neurons.
Before beginning the six-month exercise program, which was also conducted three times a week, the participants were given two weeks to see if they were doing well. In this type of exercise, high-intensity exercises are alternated with lower-intensity exercises or rest periods.
These workouts are psychologically demanding because they require a high level of motivation and resilience. Therefore, they are not suitable for everyone. At the same time, apparently due to the age of the participants, the training plan for them was relatively gentle: their heart rate during training did not exceed 154.
The volunteers also underwent MRI and PET scans to measure the amount of neuromelanin, a dark pigment in dopamine-producing neurons in the brain's substantia nigra, and dopamine transporter protein (DAT), which helps neurons maintain adequate levels of the hormone.
Six months into the study, the examination was repeated. The results of the scans astounded the medics. It turned out that the amount of neuromelanin and DAT signaling in Substantia nigra increased significantly. According to the authors, this suggests that high-intensity exercise not only slowed neurodegeneration, but also helped to improve the dopaminergic system.
Given the small sample, the scientists noted that more research is needed to confirm the findings. They urged colleagues to continue exploring the potential of exercise in the treatment of Parkinson's disease.