Caffeine-shown to increase alertness, performance, and in some studies, memory.

He said, "A 15- to 20-minute nap will increase alertness, productivity and creativity."

Stimulants are drugs that can increase alertness and awareness, usually for a short time only.

Several strategies are common in attempting to increase alertness and counteract the effects of sleep deprivation.

Coffee and other caffeinated beverages seem to increase alertness when consumed throughout the day.

Television engages the mind and can increase alertness, keeping you awake.

Drugs that increase brain activity, alertness, attention, and energy may be helpful.

All these activities can increase alertness and make it difficult to fall asleep.

Recent studies show regular napping may increase alertness and lessen the chance of dying from heart disease.

Soon the nights will be brilliant with snow, while a bit of fresh air does no one any harm and actually increases alertness.