A dad has expressed his concerns over high-caffeine energy drinks after his super-fit teenage son died in his sleep.
Rugby player Joshua Merrick, 19, was found dead in his hotel bed during a work trip with his dad. He had recently completed an intense fitness test and medical to join the Royal Navy.
And the night before he was found dead, he completed a two-hour gym session with his father.
Tests revealed Joshua had an enlarged heart, which could have been caused by excessive exercise, but the cause of death remains 'unascertained'.
However, his dad Andrew, from Didsbury, Manchester, told the inquest into his son's death: "I was concerned about him drinking high-caffeine drinks as stimulants. There is very little, if any, regulation of these products from my investigations.
"I am not saying it is a cause, I'm saying it is contributory to people who have a disposition. People have extreme lows and get palpitations when they crash.
"It is new on the market and available to everybody and rarely gets a check."
Dr Gwen Ayers found Josh had 5.8mg of caffeine per litre of blood. The normal level is up to 10mg.
She said caffeine drinks may have contributed to Josh's death if they triggered complications with his heart, which was so large it resembled of someone in their 60s with high blood pressure.
Manchester Coroner Nigel Meadows described Joshua's death as 'one of those strange things that happens on occasion with no rhyme or reason to it.'
Recording a verdict of death by natural causes, he said: "The doctors have not been able to explain an identifiable cause of death so the medical cause is unascertained.
"I agree that one explanation is a malfunction of the heart - the rhythm may have been disturbed."
He added: "As regards this issue about stimulant drinking, I agree that in some circumstances there maybe something in it but in this particular case I can't see it's played a part in his death.
"This could be described as a parent's worst nightmare. To have a fit young man suddenly die is awful."
Animal Rage contains caffeine, green tea extract, guarana, and coffee bean extract, as well as high levels of Vitamin B12, Niacin, and amino acids.
It claims to give athletes 'increased endurance, improved workouts, competitive strength and optimised focus'.
Athletes are advised only to drink one pack a day and 45 minutes prior to a training session.
Last month, a government advisor said energy drinks should be banned from schools because they are as damaging to young people as drugs.
John Vincent, co-founder of food chain Leon who's been tasked with advising on school meals, told the BBC: "Energy drinks are effectively another form of drugs. The amount of sugar and caffeine in these drinks is effectively allowing drugs into schools.
"We don't do that and in our view these drinks should not be a part of school life.
"They have hugely damaging effects on children. It affects their ability to concentrate, how they feel, and they have health effects."
More on Parentdish: Girl, 14, died after drinking Monster Energy drink