has shown that HIIT regimens produced reductions in the fat mass of the whole-body in young women comparable to prolonged moderate-intensity continuous training (MICT). Some researchers also note that HIIT requires "an extremely high level of subject motivation" and question whether the general population could safely or practically tolerate the extreme nature of the exercise regimen.

Sprint interval training (SIT) is an exercise conducted in a similar way to HIIT, but instead of using "near maximal" effort for the high-intensity