Apparently, water consumption can be a factor as well. It's best not to let your dog "tank up", especially if it is hot from exercise. If a dog drinks a fair bit, it should not then run. One day the senior vet in the clinic I use said that he always worries about "those guys" (meaning standard poodles) having a drink, running, in the yard, and twisting their guts.
In this neighbourhood, there have been three cases of bloat in the last half-dozen years: a great dane (cause unknown; he died of heart failure when they were trying to treat him), a border collie (cause unknown), and a chow (playing in the yard after dinner). (By "cause unknown", I mean I don't know it: the dane owner was barely coherent and I don't really know the border collie owner.) Only the chow survived.
Here is the PetPlace article on bloat: GDV.