Table 2.
Developmental changes in sleep variables [age 2 years (2 Y) versus 3 years (3 Y); n = 8] for morning (MN), afternoon (AN) and evening naps (EN); significant differences are indicated in bold type
| Nap | Developmental changes (2 Y, 3 Y) Paired t-tests (n = 8) |
|||
|---|---|---|---|---|
| t | d | P | ||
| Time in bed (min) | MN | 0.94 | 0.46 | 0.190 |
| AN | 3.64 | 1.19 | 0.004 | |
| EN | 1.66 | 0.76 | 0.074 | |
| Sleep duration (min) | MN | 1.88 | 0.70 | 0.051 |
| AN | 3.60 | 1.13 | 0.004 | |
| EN† | 3.07 | 1.17 | 0.011 | |
| Sleep latency (min) | MN | −1.39 | −0.68 | 0.103 |
| AN | −0.48 | −0.16 | 0.321 | |
| EN | −0.66 | −0.30 | 0.268 | |
| SWS latency (min) | MN | −1.58 | −0.28 | 0.079 |
| AN | 0.00 | 0.00 | 0.500 | |
| EN | 0.99 | 0.33 | 0.179 | |
| Stage 2 (min) | MN | 1.19 | 0.61 | 0.136 |
| AN | 1.96 | 0.87 | 0.045 | |
| EN | 1.81 | 1.06 | 0.060 | |
| Stage 2 (%)* | MN | 0.36 | 0.20 | 0.726 |
| AN | 0.66 | 0.24 | 0.528 | |
| EN | 0.78 | 0.48 | 0.467 | |
| SWS (min) | MN | 1.20 | 0.57 | 0.134 |
| AN | 2.08 | 0.63 | 0.038 | |
| EN | 0.81 | 0.43 | 0.225 | |
| SWS (%)* | MN | −0.06 | −0.03 | 0.955 |
| AN | −0.43 | −0.19 | 0.679 | |
| EN | −0.66 | −0.37 | 0.535 | |
SWS: slow wave sleep; percentage values were calculated relative to total sleep time.
*
two-tailed t-test.
†
consider result with caution because some children were awakened from their evening nap (see Methods).