Table 3.
Sleep inertia studies using measured nap sleep time
| Study | n | Mean age | Design | Factor | Subj | Obj | Time before testing | Findings |
|---|---|---|---|---|---|---|---|---|
| Brooks A and Lack L 2006 [49] | 24 | 22.5 | Nocturnal TIB of 5 hours then 3 pm afternoon nap. Crossover design with naps of 0, 5, 10, 20, 30 min sleep | Sleep duration | SSS | SDST, LCT, visual RT | 5 minutes | Improvement in SSS, LCT, and RT lapses after 10 min nap vs no nap; worsening in SSS, SDST, LCT after 30 min nap vs later performance |
| Tietzel AJ and Lack LC 2001 [50] | 12 | 21.8 | Nocturnal TIB 5 hours then counterbalanced to 3 afternoon sessions: 0, 10, 30 min sleep | Sleep duration | SSS, POMS | SDST, LCT | 5 minutes | SSS worsened only in the no-nap group; vigor and SDS worsened after 30 min nap and rest; LCT worsened after 30 min nap |
| Tietzel AJ and Lack LC 2002 [51] | 16 | 22.5 | Nocturnal TIB of 5 hours then counterbalanced to 4 afternoon sessions: 0, 30 s, 90 s, 10 min sleep | Sleep duration | SSS, POMS | SDST, LCT | 5 minutes | No effect on SSS, POMS (fatigue/vigor), SDST, or LCT |
Abbreviations: LCT=letter cancellation task, n=number analyzed, obj=objective measures, POMS=profile of mood states, RT=reaction time, SDST=symbol digit substitution task, SSS=Stanford sleepiness scale, subj=subjective measures, TIB=time in bed, vs=versus