We all know guys in the NFL take a lot of heavy hits to the body but recent studies show hits to the head will leave a lot of them mentally crippled for life.

A report recently released by the National Football League revealed three out of every 10 former NFL players is likely to develop brain conditions like Alzheimer's and Parkinson's disease at earlier ages compared to the general population.

Like Us on Facebook

Of the 19,400 former league players surveyed, some 28 percent or 6,000 men could develop Alzheimer's disease or some other form of dementia because of playing for the NFL.

The study also predicts 14 percent of all former NFL players will be diagnosed with Alzheimer's disease. Another 14 percent is expected to develop moderate dementia.

About 31 players will be diagnosed with Lou Gehrig's disease or Amyotrophic lateral sclerosis (ALS). A further 24 players will be afflicted with Parkinson's disease during their lives, according to the study.

Dementia is a broad category of brain diseases that cause long term loss of the ability to think and reason clearly. Severe dementia can affect a person's daily functioning.

Alzheimer's is the most common form of dementia. There is no cure for the disease.

Alzheimer's worsens as it progresses and eventually leads to death.

Parkinson's is a degenerative disorder of the central nervous system. The most obvious symptoms are movement-related.

These include shaking, rigidity, slowness of movement and difficulty with walking and gait. Muhammad Ali and Michael J. Fox are two celebrities afflicted by Parkinson's.

The study on brain damage among NFL players was released as supporting evidence in a class-action suit against the NFL brought by retired and active players.

The report was prepared for Senior U.S. District Judge Anita Brody, who is presiding over the class-action lawsuit in Philadelphia.

The lawsuit accuses the NFL of hiding information that linked concussions to brain injuries.

Data submitted on behalf of the plaintiff players estimates the average payouts for each player in current dollars, to be US$2.1 million for ALS.

Some $1.4 million will be paid for a death involving CTE or chronic traumatic encephalopathy. This is a neurological disorder found in professional athletes such as NFL pleyers that have experienced repetitive brain trauma

Some US$190,000 will be paid to each player for Alzheimer's or moderate dementia.

The study calculated that the NFL's proposed settlement of US$675 million will be enough to award damages to affected former players.

Besides the US$675 million for compensation, the NFL also proposed spending US$10 million for research; US$75 million for baseline assessments and US$5 million to raise awareness in the public.

This data was prepared for lawyers of the former NFL players and is now available to the public.