a 2003 study showed that alcohol ingested prior to sleep decreases REM and subsequently affects procedural memory, or our CPU. Therefore, an individual who consumes moderate amounts of alcohol immediately prior to sleep may have difficulty remembering a recently learned task. Additionally, a disruption during deep sleep can impair the imprint of recently learned information.

occurs around 5:00pm and is what accounts for the common feeling of a “second wind.” Most people usually face a slump in their level of mental acuity somewhere between noon and 2:00pm, corresponding to the post-lunch slump. Contrary to popular belief, the after-meal lethargy is actually driven by the circadian cycle and has little or nothing to do with the food we ate.

Alcohol acts as a suppressant to REM sleep, especially in the first half of the evening. Because we require the REM phase of sleep for effective learning, any alcohol consumption at or above three to four drinks prior to bedtime can decrease a person’s ability to remember specific things the next day. This memory change might not be noticeable, but it may manifest itself as a decrease in efficiency or a general fuzziness. Another problem with alcohol is that it is a diuretic, meaning it promotes urination. Even one or two drinks within a few hours of bed could result in a full bladder accompanied by a need to use the restroom in the middle of the night.

THE EAT-TURKEY-AND-SLEEP MYTH Are you one of the many Americans who has experienced difficulty staying awake after a large Thanksgiving or Christmas dinner? Or do you simply plan ahead for a post-feast snooze? Many people have suggested that because turkey contains large doses of tryptophan, it is the bird that makes you sleepy. This is not likely the case. In reality, turkey contains about the same amount of tryptophan as chicken but less than cheese or some fish such as cod. It is more likely that the drowsiness you experience is due to the massive food your body is digesting. The body must work overtime to digest large meals. As a result, the body will often divert oxygen-rich blood from other areas such as the brain to the stomach and intestines to provide them additional power. As soon as this blood is diverted from the brain, we begin to feel drowsy.

Meals high in carbohydrates accentuate this natural response. This process is indirectly related to the ingestion of tryptophan but not because of the turkey. When carbohydrates are consumed, the pancreas produces insulin to break down the carbohydrates. Insulin triggers other amino acids (not tryptophan) to move into the muscles. The tryptophan is then left behind in a higher concentration relative to the other amino acids. The tryptophan travels to the brain with little competition from the other amino acids and is converted to serotonin and then melatonin. The higher level of serotonin gives us that satisfied feeling and the melatonin stimulates sleepiness.

Any carbohydrate-rich meal can produce this postprandial (post-eating) feeling of drowsiness. What makes the Thanksgiving or Christmas meal more significant is the sheer quantity of food that is often shoveled down in a single sitting.

In particular, it is the temperature of our hands and feet that affect our sleep the most. Sleep researchers have shown that the ideal sleeping conditions are found in those environments that are cold and dark, similar to a bat cave. However, because of the sensitivity of our hands and feet, we need to have our feet warm.

Our eyelids contain photoreceptors that detect light, which is why closing your eyes in a lit room does not prevent you from seeing the light.

sleep tonic. Many people will drink a glass of alcohol before bed to help them fall asleep. Alcohol helps you fall asleep because it decreases sleep latency. The problem is, it also inhibits dream sleep, thereby reducing the quality of sleep needed for optimal functioning the following day.