A human's "reaction time" is the amount of time it takes for a person to respond to stimuli, or to perform simple reflexive functions. Reaction time is generally related to reflex, the involuntary movement in response to a stimuli. To slow a reflex is to slow the consciousness and coordination of an individual, which mainly happens by external circumstances.
These circumstances are seemingly endless. Nearly any event can speed up or slow down reaction time, but certain factors have a greater influence than others, one of which being the amount of sleep a person gets.
Sleep deprivation can have serious effects on the body, and they all stem from reaction time being slowed. The less sleep a person gets, the less capable he/she will be to perform all of the body's functions as precisely as possible. In fact, studies show that a person lacking sleep will operate on a similar level as a person intoxicated with alcohol.
While the body would still be able to perform all its regular functions, fine motor skills would be seriously restricted, and precision in any task would decrease tremendously. Response to stimulus would be delayed; alertness and attention span would diminish with each hour of lost sleep. Any simple task like driving to work could become dangerous, as the body may not be able to counter the unexpected.
The greatest danger that can arise from sleep deprivation is slowed reaction time. Since reaction time is essentially the body's ability to perform its functions as best as possible, any problem that occurs can be directly related to too much time lapsing between a stimuli and response.
Age also affects reaction time. As a person gets older, his/her muscle movement becomes slowed and unable to respond as quickly as the muscles of a younger person. Reflexes are at their best in a person's teens and twenties. Exercise also relates to this, as reflexes can be maintained at older ages through regular exercise and constant alertness.
The corpus callosum is a group of neural fibers in the middle of the brain that connects the left and right side. As a person gets older, this becomes weaker, and begins to divide the two sides instead of connect them. This can be a major reason why areas of the brain, like fine motor skills, deteriorate with age. The direct correlation between fine motor skills and reaction time causes reaction time to worsen with age.
The art of today's generation seems to be multi-tasking, but multi-tasking is very unhealthy for the brain. By doing more than one thing at a time, the brain learns to divide its attention to each task rather than spend more time on one specific task. While a person is doing multiple things at a time, he/she is actually focusing less, therefore decreasing reaction time. Such activities like texting or talking on the phone while driving or listening to music while doing homework can seriously slow reaction time and ultimately result in consequences.
Numerous other factors can have an effect on reaction time. Alcohol, just like sleep loss, can impair reaction time and judgment with each sip consumed. According to studies, an increased intake of sugar and caffeine can actually increase reaction time. Obesity can lower reaction time, as muscles will not be able to move as quickly, while an unhealthy diet can release excess lactic acid to the muscles and lower reaction time as well.
Illness or disease can have major effects on reaction time. When the body is sick, many of its regular functions become impaired or shut down altogether in order to preserve energy and fight against the infection. The brain won't be able to act as quickly as it would if fully functioning, and reactions will become delayed.
Any type of distraction should also be accounted for when considering reaction time. While all of the above factors can be considered distractions, things like sex, love, grief, pain, or other emotions can divert attention from any unexpected stimuli that may occur. Emotions are strong enough to control a person's life for the time being, and reaction time becomes greatly influenced because of this.