Reduction and minimum TST

The reduction of sleep compared to your baseline sleep-requirement, is one of the goals achievable through adaptation to polyphasic schedules.

The amount of sleep that can be reduced is highly individual, depending on age, genetics (-> RSR), and many more, but the most reducing schedule that is possible for most is MonoCore-2, with M3 (in the 4.5h variant) also being possible for some but not many. For those who prefer DualCore, DC1 is a similar level of reduction.