Parkinson’s disease is a progressive condition of the nervous system, which affects movement. According to the NHS, one in 500 people are affected by Parkinson’s disease, equating to an estimated 127,000 people in the UK with the condition.
A variety of symptoms are associated with Parkinson’s. These can differ in severity, and can arise at different stages of the disease. It is very unlikely that someone diagnosed with Parkinson’s disease will ever experience all of these symptoms.
The symptoms of Parkinson’s come in two groups, physical and mental. Physical symptoms include:
- Shaking/muscle tremors: muscle tremors are usually one of the first, and most well-known, symptom of Parkinson’s. Tremors usually start in the forefinger and thumb, and will progressively travel down the hand and into the arm as the condition becomes more severe.
- Hypokinesia (slowness of movement): another commonly associated symptom of Parkinson’s, hypokinesia is the reduction in the speed of the entire moving process, from noticing a stimuli that makes you want to move, planning to move and actually moving.
- Rigidity: the muscles become tense and stiff, making movements painful, and resulting in cramp.
- Impaired balance: problems balancing are more likely to develop in the later stages of Parkinson’s, and can result in a stooped posture, as well as being prone to falls.
Other (less common) physical problems include:
- Facial changes: you may have difficulty using facial muscles
- Nerve pain
- Loss of smell
- Erectile dysfunction
- For women, difficulty becoming aroused and achieving orgasm
- Dizziness and blurred vision
Parkinson’s also affects cognitive function, and can result in behavioural changes. Symptoms of this can include:
- Impulse control problems
- Memory problems
- Symptoms associated with dementia: personality changes, delusions and hallucinations
When neurones in the substantia nigra are functioning properly, they produce a neurotransmitter called dopamine. Dopamine’s role is to send chemical messages to nerve cells in the brain and nervous system that are responsible for movement.
In the case of Parkinson’s, the nerve cells that produce dopamine deteriorate, subsequently lowering the amount of dopamine that is produced. As a result of the loss of dopamine, the portion of the brain that controls movement can’t function properly.
The deterioration of nerve cells is a very slow process, and is usually only noticed once 80 per cent of the substantia nigra nerve cells are already gone.
For the majority of people, Parkinson’s is idiopathic, meaning no specific cause is known. Currently, researchers believe that the loss of nerve cells is the result of a combination of genetic and environmental factors. 15 per cent of people with Parkinson’s disease have a close relative that also has Parkinson’s 
Some researchers believe that environmental stimuli may also factor into the development of Parkinson’s. Specifically, pesticides and herbicides that are used in farming, although the evidence of this is currently inconclusive. 
Although not much is known on why Parkinson’s occurs, there are certain lifestyle changes that can be made which may lower the risk of developing Parkinson’s.
Exercising, even in middle age, is thought to reduce the risk of developing Parkinson’s later in life.  Exercise’s ability to reduce inflammation and insulin resistance, stimulate the release of growth factors, and relieve stress, are all secondary benefits of exercise.
The true benefit is the effect exercise has on brain functioning. Regular exercisers have been shown to have higher scores on cognitive functioning tests (tests that measure attentional control, inhibitory control, cognitive flexibility, working memory updating and capacity, declarative memory, spatial memory, and information processing speed). Exercise is also thought to actually stimulate neuron growth in the brain. 
Studies have also shown that caffeine may help to lower the risk of developing Parkinson’s.  Consuming lots of foods that contain high amounts of antioxidants (such as strawberries, tomatoes, acai berries, oranges, cherries, blueberries, dark (raw) chocolate, artichoke, kale and kidney beans), may have preventative qualities, although evidence so far has been inconclusive. 
Tobacco smoke has been linked to lower risks of developing Parkinson’s, although the adverse health effects of smoking do not outweigh the decreased risk of Parkinson’s.