David Myers toured Australia with the Great Britain team
A former Great Britain rugby league player who had a heart attack while driving on the M6 was using steroids and amphetamines, an inquest heard.
David Myers, 37, had traces of both substances in his blood and Cheshire Coroner Nicholas Rheinberg ruled they may have contributed to his death.
He died when his van hit a bridge support in Cheshire in October 2008.
A family of six later died when their people carrier was hit by a lorry as traffic queued after the first crash.
David and Michelle Statham and their four children were returning home to North Wales when they were killed.
An inquest at Crewe Municipal Buildings heard Mr Myers had been working as a van driver and nightclub doorman following his retirement from rugby.
His partner, Sarah Southern, told the inquest he was a "keep-fit fanatic" but was working "terrifically long hours".
She said he hoped to return to playing rugby and had obtained a coaching certificate shortly before the crash on 20 October.
Asked by Mr Rheinberg what drove him to work so much, she said: "He needed the money."
Questioned further about his use of amphetamines, Miss Southern said she was not aware of him using them.
She added: "He may have taken things to keep him awake at work."
Miss Southern told the court that on the night before he died, her partner had complained of tiredness and chest pains and had planned to see a doctor.
David Myers died in one of two fatal crashes on the M6
Witnesses to his crash described how Mr Myers' van overtook two vehicles on the northbound carriageway of the motorway and then swerved as it returned to the middle lane.
The van then crashed through a barrier protecting a railway bridge at high speed and hit the bridge itself.
Pathologist Dr Paul Simcock told the hearing a post-mortem examination found Mr Myers suffered little more than minor cuts to his head during the crash, but his heart was twice the normal size.
Dr Simcock said: "Mr Myers was a very fit man and the heart does enlarge when you are fit, nevertheless his heart was over and above what I would have expected to have seen."
He said toxicology reports found traces of paracetamol and codeine as well as the amphetamines and anabolic steroids.
Mr Myers played for Wigan between 1990 and 1992 and had two spells with Widnes.
He toured Australia with Great Britain in 1992.
Mr Rheinberg recorded a verdict of natural causes "to which amphetamine and anabolic steroid use contributed".
The separate crash involving chef Mr Statham, 38, and his 33-year-old wife and their children happened about 90 minutes after the crash involving Mr Myers' van.
Paulo Jorge Nogueira da Silva's 40-tonne lorry hit their car as it waited in tailbacks.
Mr and Mrs Statham died instantly at the scene along with sons Reece, 13, Jay, nine, and Mason, 20 months, and 10-week-old baby daughter Ellouise.
Da Silva, 46, of Murcia, in Spain, was jailed for three years at Chester Crown Court in February for causing their deaths by careless driving.