# Mastering Sleep/Introduction
## Sleep
### Going to Sleep

Avoid drinking caffeine, which is a stimulant that can make it harder to sleep. If one must drink caffeine to stay awake during the day, it should be done several hours before the target bedtime. Also avoid strenuous exercise within a few hours of bedtime. Although intense physical activity is exhausting, doing it shortly before bed can wake up the body more.

### Waking Up

Sleep inertia is a physiological state characterized by a decline in motor dexterity and a subjective feeling of grogginess immediately following an abrupt awakening. The impaired alertness may interfere with the ability to perform mental or physical tasks. Sleep inertia can also refer to the tendency of a person to want to return to sleeping.
In other words, it's easy to fall back asleep after the alarm has gone off, often multiple times! How are we to overcome this hindrance? It takes 15-20 minutes for the body to overcome the desire to go back to bed after waking up, the last thing you should do is lie back down in bed! People have many different methods to try wake up on time, however unsuccessful they may be.
One might begin by having multiple alarms at different times, and at different places in the room. Alarms can cause you to have intense sleep inertia if your are not awoken at an arousal point (semi-awake state) during your sleep. The product WakeMate claims to wake you at these arousal points, to avoid sleep inertia. The product monitors motion during sleep, and uses actigraphy to analyze and decide to sound the alarm.
If multiple alarms don't work, it is advised to create some obstacles (chairs and the like) to the alarm clock. Moving the obstacles will take more time and will get your blood flowing a little bit. Stretching (especially around the neck and shoulders) might also help, as the body can become very sore from lying down for so long. If you don't find it easy to fall asleep in a chair, you may set one beside your alarm clock so you may sit for 15-20 min (instead of lying down) and wake up.

### Polyphasic

Polyphasic sleeping refers to trading core sleep for 20-minute naps during the day. The conversion is generally one 20-minute nap for 1.5 hours of core sleep. These naps should be as evenly spaced out as possible, but may be moved according to your schedule.
| Sleep Schedule | Total Amount of Sleep (hours) | Amount of Core Sleep (hours) | Number of 20-min Naps |
| Monophasic | 8 | 8 | none |
| Siesta | 6.3 | 6 | 1 |
| 2-nap Everyman | 5.2 | 3.5 | 2 |
| 3-nap Everyman | 4 | 3 | 3 |
| 4-nap Everyman | 2.8 | 1.5 | 4 or 5 |
| Uberman | 2 | 0 | 6 |
| Dymaxion | 2 | 0 | 4 30-min naps |
The Everyman polyphasic schedule is most common since it can easily be adapted to a normal work schedule. For example, one might sleep from midnight to 3am, taking naps at 7:30, noon, and 6pm. To account for a typical work schedule, the naps are not evenly spaced.
The Uberman is considered the most difficult of the 20-min nap variety. There is no core sleep, and the naps can't be missed by more than 30 minutes or you will feel very tired! This is in contrast to the Everyman schedule, where naps may be missed by a few hours without much consequence.
The Dymaxion is known to be more difficult than the Uberman because the body's tendency to fall into deep sleep after 20 minutes, making it very difficult to wake from a nap.