Agreed. We're also slowly learning more about the required aerobic intensity to halt disease progression.

For example, the knowledge gained from the recent SPARX trial [1] (mentioned in the article) where participants were assigned to one of three groups: control, moderate-intensity treadmill exercise (60 to 65 percent maximum heart rate) or high-intensity treadmill exercise (80 to 85 percent maximum heart rate). After six months researchers found that the motor symptoms of only the high-intensity group had not progressed.

[1] Effect of High-Intensity Treadmill Exercise on Motor Symptoms in Patients With De Novo Parkinson Disease: A Phase 2 Randomized Clinical Trial, Margaret Schenkman et al., JAMA Neurology: 75(2) 2018.