a native hydrous magnesium silicate, sometimes with a small amount of aluminum silicate; used as a dusting powder. The inhalation of talc is associated with a wide variety of respiratory disorders.
Factors contributing to poor sleep include vitamin and mineral deficiencies. Magnesium deficiency can cause insomnia; lack of potassium can lead to difficulty staying asleep; and vitamin D deficiency has been linked to excessive daytime sleepiness.
Like deep sleep, REM sleep is associated with increased production of proteins. One study found that REM sleep affects learning of certain mental skills. People taught a skill and then deprived of non-REM sleep could recall what they had learned after sleeping, while people deprived of REM sleep could not.