An ambulance was called to Grouville at around 4 am, just an hour after the 48 mile endurance event got underway, early on Saturday morning.
It’s believed the man suffered a heart attack and was resuscitated by one of his fellow walkers.
The Health department say he’s in a stable condition this morning.
Nearly 1,300 walkers trekked their way around the Island’s shoreline on Saturday in the tough 48-mile round Island walk.
It’s now in its 26th year and this year raised money for St John Ambulance, Durrell, Jersey Cheshire Home, Teenage Cancer Trust Jersey Appeal, Jersey Mencap, Silkworth, Les Amis, Ridout House and Age Concern Jersey.