any lifeguards have appreciated the fact that any movement and mild exercise during surveillance tasks can stimulate the muscles and increase blood flow, which oxygenates the brain.
The explanation for this phenomenon is quite complex: Specifically, human attention requires stimulation of two major areas of the brain to function properly, according to Drs. Fred Plum and Jerome Posner in their neurophysiology text The Diagnosis of Stupor and Coma of 1972: The Ascending Reticular Activation System (ARAS) in the upper brain stem and areas of the cerebral cortex.
The ARAS receives additional pathways from, and is stimulated by, every major somatic (organ) and every sensory (nerve) pathway. Simply stated, visual stimuli — as well as stimuli from our muscle groups, centers from respiration and increased sympathetic tone from even minimal exertion — all feed into the ARAS. This area then primes the brain cortex for stimulus reception that, in turn, focuses this arousal energy for heightened arousal.
The prefrontal cortex of the dominant right hemisphere helps maintain attention, and the parietal cortex plays a role in shifting attention. These zones with their limbic connections are the “attentional gate or environmental monitor” for sensory stimulation back to the thalamic portion of the brain.
It is important to understand that this complicated and sophisticated input/feedback system requires the individual to be well-rested and not overly stimulated so he or she can maintain a higher level of vigilance.
This explanation also helps to illustrate why the increased movement, respiration and heart rate of the lifeguard serves to stimulate the neurological pathways for improved attention and concentration.
