[ska]

It seems more likely that we are all biologically predisposed to function badly on such a schedule.

Some people probably deal with the deficits better than others, but all of the "positive" results from something that extreme I've heard of are subjective and self-reported, so not worth much as evidence. There is, however, lots of empirical data about loss of cognitive function due to sleep deprivation; to be fair I don't think any of the studies I've seen targeted precisely that (self imposed, cyclic) sort of pattern. On the other hand, none of that research suggests a good outcome would be expected. I'm not referring to all sleep patterns here, just those that rely on very short cycles, e.g. 20 min.