Chris Johnson Life Expectancy
Former NFL star Chris Johnson has opened up about his ALS diagnosis and his determination to keep fighting for his wife and four children Chris Johnson/Instagram

Former NFL star Chris Johnson has written an emotional letter to his four children as he battles amyotrophic lateral sclerosis (ALS), confronting an uncertain future while revealing that his family remains his 'biggest reason I keep fighting.'

The letter has also renewed questions about Chris Johnson's life expectancy, although ALS experts stress that survival varies significantly from person to person.

Chris Johnson Life Expectancy: What ALS Experts Say

There is currently no cure for ALS, a progressive neurodegenerative disease that damages motor neurons responsible for voluntary movement.

According to the ALS Association, typical life expectancy following an ALS diagnosis is two to five years, but there is no single timeline for the disease. The organisation says average survival is around three years, while about 20% of patients live five years or longer, 10% survive at least 10 years and roughly 5% live for 20 years or more.

Those figures are population-level statistics and should not be interpreted as a prediction of Johnson's individual prognosis.

Johnson, 40, has said his case is sporadic ALS, meaning there is no known family history. The ALS Association says about 90 per cent of ALS cases are sporadic.

Chris Johnson Reveals How His ALS Symptoms Began

Johnson recalled in his Players' Tribune letter that something initially felt wrong with his right hand. During a family road trip, even his water bottle began feeling unusually heavy.

He eventually underwent a nerve conduction study in Nashville. Johnson said the results prompted doctors to recommend further investigation, beginning a process that ultimately led to his ALS diagnosis.

ALS can be difficult to diagnose because there is no single test that confirms the disease. Early warning signs, including muscle weakness, slurred speech and difficulty gripping objects, can resemble symptoms of other conditions.

Johnson publicly revealed his diagnosis in June, saying the disease had progressed rapidly. He recalled being able to pick up his seven-year-old daughter for her birthday little more than a year earlier, something he could no longer do.

Chris Johnson Writes Heartbreaking Letter to His Kids

Addressing Honey Buns, CJ, Kaden and Lee, Johnson urged his children to remain close regardless of what the future brings.

He wrote about his hopes of watching them graduate, seeing his sons become men, walking his daughter down the aisle, meeting future grandchildren and growing old with his wife, Brittany.

Johnson also described how his children's ability to joke with him and maintain a sense of normality helps him temporarily forget the impact of ALS.

'You guys are my biggest reason I keep fighting,' he wrote.

Clinical Trials Offer Hope Amid ALS Battle

Johnson has said he is participating in clinical trials as researchers search for new ways to treat ALS. The ALS Association said the growing pipeline of experimental treatments provides reason for hope, while emphasising that the disease remains fatal.

The organisation has highlighted Qalsody, or tofersen, an FDA-approved gene-targeted therapy for ALS associated with mutations in the SOD1 gene. Johnson has not said he is receiving Qalsody, and his description of his condition as sporadic ALS does not establish whether he would be eligible for the treatment.

Chris Johnson's NFL Career Before ALS Diagnosis

Johnson spent 10 seasons in the NFL after being selected by the Tennessee Titans in the first round of the 2008 draft. The three-time Pro Bowler became one of only nine players in NFL history to rush for more than 2,000 yards in a season after recording 2,006 yards in 2009.

Since making his diagnosis public, Johnson has used his platform to raise awareness of ALS and its potentially rapid progression while continuing his treatment and clinical trial participation.

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