A top neurologist who was living a healthy and active life received a shock Parkinson's disease diagnosis in his forties.

Knowing exercise was the key to maintaining good neurological health, Dr David Blacker, from Perth, was a keen marathon runner until he started experiencing a strange pain in his leg that got progressively worse. 

The dad told FEMAIL he chalked the issue up to a muscle strain but when he started to notice tremors and issues with his dexterity, he knew something more sinister was going on. 

In 2018, Dr Blacker was diagnosed with Parkinson's disease and while he said the news was a 'kick in the gut' he didn't let it stop him from leading an active life. 

The 55-year-old wants Australians to know Parkinson's doesn't mean a gradual and painful decline and that the symptoms can be eased with regular exercise and healthy lifestyle choices.

Neurologist Dr David Blacker (pictured), 55, from Perth, was diagnosed with young-onset Parkinson's Disease in his forties despite leading a healthy active life

In his mid-forties, Dr Blacker was prioritising keeping fit and exercising regularly as he knew of its impact on neurological health. 

'I had been working with stroke patients for a long time and realised the benefits of exercise. It's one of the reasons I was really trying to maintain exercise myself,' he said. 

'I was actively trying to do that and if I hadn't been maybe I would have had my symptoms earlier.'

The doctor started noticing a pain in his leg which he thought to be an exercise-induced dystonia that causes the muscles to contract uncontrollably. 

'Initially, I thought it was because I had been doing too much, that I'd been trying too hard without adequate rest and stretching,' he said. 

'I got to a point where my foot started twisting and tightening up and then it would worsen with my whole leg – it was like running in quicksand.'

Over the next three years, Dr Blacker's pain got progressively worse. Then he started noticing more 'classic' signs of Parkinson's disease. 

'I would get a shake in the right hand and initially, it was only when I was stressed or public speaking or something like that,' he recalled.

'Everyone criticises doctors' handwriting, but my writing became really tough and I had trouble filling out forms, it was very getting difficult.'

Dr Blacker was an avid golfer and noticed he would have trouble with his fine motor skills when he would try to fish a ball out of his pocket or put it on a tee. 

'The real kicker was when I was seeing patients who had Parkinson's disease and they were performing better than myself.' 

Parkinson's Disease: What are the signs and symptoms?

Dr David Blacker said there are three stand out signs someone could have Parkinson's disease. 

People with Parkinson's disease will receive a clinical diagnosis from their doctor as it doesn't show up on tests. 

Neurologists will gather a full picture of a patient's symptoms and lifestyle. If someone presents with two out of the three key features, they will usually be diagnosed with Parkinson's. 

1. Tremor -  'The tremor is typically when you're resting and not moving your hand,' Dr Blacker said. 

'There are other tremors that are more prominent in other positions, like, if you're trying to hold things but if you're just resting, it's called a resting tremor.'

Dr Blacker said around 30 per cent of people with Parkinson's don't have a tremor despite it being widely associated with the disease. 

2. Bradykinesia - Dr Blacker said this is a type of 'slow movement'. 

'One of the common tests will do is get the patient to rapidly tap their thumbs to the index finger,' he said.  

'I'm a right hander but my left hand is was much quicker doing it.'

3. Rigidity - This is a tightness in the arms and legs beyond what would be the result of general ageing or arthritis and can lead to poor mobility. 

'It's a stiffness and soreness which is quite painful at times,' Dr Blacker said. 

There are some other signs of Parkinson's that could lead to a Parkinson's diagnosis according to Dr Blacker including a loss of smell and REM sleep behaviour disturbance. 

'When you're sleeping and dreaming you go to a deeper phase of sleep where your muscles in the limbs are paralysed, and your respiratory muscles and your eye muscles are the only things that still working otherwise you jump, jump up and run around,' Dr Blacker explained. 

'What happens in this disorder is you get very vivid dreams and interruptions to sleep and you start yelling and kicking and thrashing.'

More signs include constipation as well as undiagnosed and unexplained depression and other 'prodromal symptoms' like anxiety, mood swings, irritability, anger and sleep disturbances. 

'I started thinking, "Could it be something else? Is it too much coffee? I'm a bit young for Parkinson's disease". Then I started thinking, "Oh god, it really does look like it" but I didn't want to be hypochondriac,' he said. 

In 2018, he 'summoned up the courage' to see a fellow neurologist and he was diagnosed with young-onset Parkinson's Disease at just 49 years old.   

'I was very prepared personally and knew what it was. To some degree, I was relieved it was Parkinson's and not something that was going to be more rapid,' he said.

'Still, it was an amazing kick in the gut and there is certainly a grief process that happens.

'You have a certain picture about what your life's going to be like and what you're going to be doing in the future then when something like this happens it has to be reconfigured.'

Dr Blacker was as determined as ever to not let his Parkinson's get in the way of his active life. 

He started medication which eased his symptoms, took up boxing and yoga and swapped running for brisk walks. 

'I've been very fortunate that I've had a good response to medicines but more importantly, exercise has been my saviour,' he said. 

'We have an opportunity to reshape the course of Parkinson's disease and build up enough muscular strength and fitness that will hopefully ward off the decline as the future continues.'

After his diagnosis, Dr Blacker continued to keep up with his exercise. He took up boxing, started yoga and swapped running for brisk walks

He also adopted a Mediterranean diet which is high in fish olive oil, nuts and berries and low in red meat and dairy.

The Mediterranean diet is said to be one of the healthiest in the world as people living in that part of the world live longer healthier lives with a low rate of chronic conditions. 

Dr Blacker said his diagnosis has helped him with his Parkinson's patients at work. 

'It's a stressful time, for many people getting the diagnosis is the worst moment of their life and it really sticks in their brains. If the delivering doctor is not doing a good job, that can have a negative effect,' he said. 

'I've got this amazing opportunity to be able to deliver the diagnosis with authenticity and empathy and understand it. I can pick it with a lot more confidence than I used to.' 

'I've been very fortunate that I've had a good response to medicines but more importantly, exercise has been my saviour,' he said 

People often picture an 'old white shaky man' when they think of Parkinson's disease but Dr Blacker said it can affect people of any age, gender and race. 

The stereotype also leads people to believe a person will become immobile after a diagnosis. 

Dr Blacker said people were surprised to see him feeling and looking fit after his diagnosis. 

'One of the things I found frustrating was as I started to get fitter and stronger, people said, "Wow, you look great!", but no one sees that you have taken all these tablets or had a bad night's sleep so you're feeling really tired. There's all those non-motor symptoms people can't see,' he said. 

'People are only trying to encourage you, but you feel a bit invalidated and think, "Don't they believe me?". It's a tough psychological thing. I forewarn a lot of people about that.'

Dr Blacker wants to dispel the myth that a Parkinson's diagnosis means a linear gradual decline. 

'I think that's a bit of a misrepresentation of what actually happens. If you really get stuck into exercise and follow a good diet, that in combination with medications can have some amazing results,' he said. 

'One of my crusades is to offer a much more positive picture to people. Particularly at the at the onset, when you've given them a diagnosis.'

EXCLUSIVEREAD MORE: I'm 42 and have spent the past 21 years battling cancer after suffering a common pain at university - this is what I want all Aussies to know and why I consider myself lucky every day