“You’ll look sweet… upon the seat of a bicycle built for two.” It’s a lovely song by Harry Dacre, but it may also be a way to relieve the symptoms of a debilitating condition that has long been without effective treatment options. The tandem bike is also the focus of one of the Top 10 Medical Innovations for 2010 at Cleveland Clinic.

People who suffer from Parkinson’s disease slowly lose their ability to control the body’s movement. Tremors, difficulty with balance, changes in speech, and slowness are the major symptoms of this brain disorder that affects more than 1 million Americans and has no cure.

Parkinson's wreaks havoc by affecting nerve cells in the brain that make the neurotransmitter called dopamine. It's dopamine that sends signals to the part of the brain that controls movement, allowing muscles to move on command. With Parkinson's, however, these special nerve cells break down, the supply of dopamine dwindles, and movement is affected. That’s where the bicycle built for two comes in.

While there are a number of useful medications that help ease Parkinson’s disease symptoms for a few hours, advancements in significant relief have eluded the medical system. Until now. In a surprising and somewhat whimsical discovery, it has been found that tandem cycling may bring a longer respite from the disease—stemming symptoms for weeks at a time.

“After 50 miles [of tandem biking] the patient’s hand tremors had suddenly disappeared.”

A scientist pedaling at 80-90 revolutions per minute (RPM) captained the bike, while a friend with Parkinson's took the back of a tandem bike. After about one hour on the bike, the scientist noticed that his friend's tremors had diminished.

In the researcher's mind, the mysterious side effect of the tandem bike ride held an intriguing medical possibility: Motor control in the arms and hands improved even though it was only the legs that were exercising. Perhaps there was some change taking place in the central nervous system that triggered the release of biochemicals to improve global motor function.

Typically, a patient with Parkinson's riding a bike maintains a pedaling rate of around 50-60 RPMs. However, a non-Parkinson's captain on a tandem bike can increase that cadence to around 90 RPMs, an intense workout for any gym-goer. Pedaling at rates faster than the patient can achieve voluntarily may be driving the central nervous system of the Parkinson's disease patient which may result in an increase in the release of dopamine, which would explain the global improvement in motor functioning.

A small eight-week study was launched to gauge the effects of forced exercise. It sounds more extreme than it is—“forced exercise” is simply tandem riding in which patients are required to pedal 80-90 RPM. The effect on Parkinson's symptoms was impressive: There was a 35% improvement in motor functioning for the patients who did the forced exercise compared with those exercisers who pedaled a stationary bike at their own pace.

The improvement lasted for four weeks after the cycling sessions ended, although it tapered gradually over time, which means that, just like everyone else who starts a workout program, Parkinson’s patients must be consistent in this type of physical activity to see continued results. The need for regular, ongoing forced exercise is a significant part of this exercise therapy.

Although the workout focuses on pushing the lower half of the body beyond its comfort zone, it’s believed that the upper half improves as a result of this training as well. The question of whether the exercise is needed to stimulate the central nervous system is still unresolved, but it has proved to be one way to meet the goal of being as symptom-free as possible.

Further studies are now ongoing, but the next time you see a tandem bicycle, you may look at it as more than a quirky way to ride in the park—it’s also a medical tool that’s bringing relief to Parkinson’s patients.