How much sleep you need
Recommendations from the US National Sleep Foundation and the American Academy of Sleep Medicine, used by the CDC:
| Age | Recommended per day |
|---|---|
| Newborns (0 to 3 months) | 14 to 17 hours |
| Infants (4 to 12 months) | 12 to 16 hours incl. naps |
| Toddlers (1 to 2 years) | 11 to 14 hours incl. naps |
| Preschool (3 to 5 years) | 10 to 13 hours incl. naps |
| School age (6 to 12 years) | 9 to 12 hours |
| Teens (13 to 18 years) | 8 to 10 hours |
| Adults (18 to 60 years) | 7 hours or more |
| Adults 61 to 64 years | 7 to 9 hours |
| 65 and older | 7 to 8 hours |
About sleep cycles
A night moves through light sleep, deep sleep and REM sleep several times. Each round lasts about 70 to 120 minutes, with 90 minutes a common average, and later cycles contain more REM. The 90-minute rule is an approximation: your own cycles vary from night to night, so treat these times as a guide. If you often wake tired after enough hours, or snore heavily, talk to a doctor; sleep apnea is common and treatable.
Sleeping better
Keep the same wake time every day, including weekends. Get daylight in the morning, keep the bedroom dark and cool, and avoid caffeine after early afternoon and alcohol close to bedtime. Most adults who sleep less than 7 hours regularly are in what the CDC calls short sleep, linked to higher risk of obesity, diabetes, heart disease and depression.