A consistent premise throughout this book has been the separation or differentiation between forced submersions and dives. This has been justified for psychogenic reasons, experimental protocol, and results. Nevertheless, in a recent review, Blix (1987) has proposed that the difference is a matter of degree more than of substance. This would mean that extended dives are essentially the same as forced submersions. In both cases the diver is prepared for a long and, at least in the one case, unknown breath-hold duration. I have doubts that the two are completely comparable. In Table 14.1 I have summarized some of the similarities and qualitative differences among forced submersions, extended dives, and bout dives. In these comparisons major differences are the character of muscle activity, LA accumulation, mental attitude, and possible concentrations of catecholamines. The point of view that there is no qualitative difference and that forced submersion and diving represent a difference of degree only is an interesting and important issue. It pleads for further investigation.