Australian scientists are attempting to make a pill containing many of the benefits of exercise.

But it won't be medicine for lazy couch potatoes.

The futuristic therapy is designed to help immobile patients unable to exert themselves at an intensity that delivers the rewards of physical activity.

Australian National University researchers could have already discovered the key to making it a reality.

They've identified unique molecular messages that travel to our brains and potentially our eyes immediately after exercise.

The team believes it may be possible to hijack these and bundle them into a vitamin-like supplement that delivers some of the benefits of physical activity.

They've also unearthed some "promising" results into the benefits of exercise on the retina, which converts light into neural signals that are sent to the brain.

They're now studying the molecular signals' impact on the central nervous system, retinal health and eye diseases such as macular degeneration.

"The beneficial messages being sent to the central nervous system during exercise are packaged up in what is known as lipid particles," vision scientist Riccardo Natoli says.

Researchers are working towards isolating these particles so they can potentially be re-coded and placed in a pill.

"Our goal is to figure out what these molecules are communicating to the body and how they're communicating," Professor Natoli said.

They say it has potential to help patients suffering from neurological diseases such as Alzheimer's and Parkinson's who are unable to exercise.

Vision scientist Joshua Chu-Tan says physical exertion is thought to slow down the progression of neurodegenerative diseases and in some cases reduce patients' symptoms.

"We know that from looking at diseases like Alzheimer's and Parkinson's, if you exercise in a particular fashion you can potentially stimulate neuronal activity,' he said.

"We want to understand the molecular messages that underpin the benefits of exercise."

The research was published in Clinical and Experimental Ophthalmology on Wednesday.