Bond market flashes yield curve warning Should this harbinger of bad news hold, the US economy is nearly certainly looking at a slowdown if not an outright recession. It is not a sure indicator, however, with an inversion in 1966 and a very flat curve in 1998 failing to lead to recessions.
Arsenal duo Henrikh Mkhitaryan and Shkodran Mustafi are also seen in the video, although it is unclear whether the pair took part in inhaling the balloon alongside their teammates.
It is not illegal to possess nitrous oxide, but it is against British law to sell or give the drug to anybody else.
The North London club sit in fifth in the Premier League table, only behind fourth-placed Chelsea on goal difference.
Arsenal started the campaign with consecutive defeats to Manchester City and Chelsea but have embarked on a brilliant 20-game unbeaten run under new boss Unai Emery.