Over the past few decades, tremendous advancements have been achieved in the area of workplace safety, The mandates of ANSI and OSHA, along with an ever-growing concern about worker safety, have focused the energies of industry on the processes with which we operate with a keen eye toward safety. And, that focus continues to pay huge dividends.
However, there are some aspects of our daily operations that have yet to receive the proper degree of scrutiny with respect to overall employee safety as well as job performance. One such area is the proper hydration of workers during the work day, There is a growing body of evidence that supports the idea that dehydration, even mild dehydration, can impair an individual’s performance significantly, And, while we tend to think of dehydration and its effects in terms of physical activity, personal dehydration can also occur in relatively sedentary environments, such as homes or offices.
Water is the single largest component of the human body, accounting for about 50 to 60 percent of body mass. And, interestingly, that water volume turns over (or is replaced) at a rate higher than any other body component, About 5 to 10 percent of the total body water is renewed every day. The sources of normal daily water loss include urination (about 1400 ml), defecation (200 ml), normal breathing (400 ml) and loss via the skin (500 ml), Obviously, these totals can change depending on the individual and their daily routine, including movement (work or exercise) and other factors. So, water replenishment is important to every worker, those who perform manual labor as well as those in offices and other business environments.
Dehydration and cognitive performance
The science of cognitive neuropsychology investigates brain behavior relationships, using objective tools to tie biological and behavior aspects together, This approach is relatively new, in that it is an outgrowth of work done linking dehydration to physical performance. It is a proven fact that physical activity itself increases dehydration, which when left unaddressed limits optimal physical performance. Can the same be said for slower increasing dehydration in non-strenuous environments, like offices and plants?
While data in this area is somewhat limited, indications are that marked decreases in physical, visuomotor, psychomotor and cognitive performance can occur when as little as two percent of an individual’s body weight is lost due to various body functions and outside influences,
Several studies have indicated that in heat induced dehydration the subjects’ general perceptions of their level of fatigue, discrimination of visual cues, visual motor tracking and short-term memory, long-term memory recall, attention and arithmetic efficiency were all adversely affected1.
To evaluate the differences between heat induced and normal exercise induced dehydration, Cian and colleagues2 conducted a study that concluded that, at dehydration levels equivalent to a loss of 2.8 percent of body weight, both heat and exercise induced dehydration resulted in increased fatigue, increased tracking errors, increased reaction time to making a decision and decreased short-term memory were encountered.
It is readily apparent that at virtually any level, dehydration is not conducive to optimal performance, be it physical or mental, Consider the consequences in, for example, a middle school, where teachers might restrict students from obtaining a drink of water during the day so as not to disrupt the class. This absolutely wellintentioned action could result in less than optimal performance from individuals in the classroom. The same situation and results hold true for adults at work.
Earlier research3, which has since been confirmed a number of times4 established that human reliance on thirst as a motivator for rehydration is insufficient, Pitts and colleagues, the authors of the original study, were quoted as saying “It should be emphasized that during work men never voluntarily drink as much water as they sweat, even though this is advantageous for maintaining heat balance, but usually drink at a rate approximating about twothirds of the water loss in sweat.” So, relying on thirst as a motivator to rehydrate, which is the most popular assumption, can lead to a declining hydrated status… further exacerbating potential performance and safety issues on the job.
Making hydration easy and enjoyable
So, hydration on the job enhances performance, concentration and, thereby, safety. But, what is one to do to stimulate greater desire in your employees to maintain the proper level of hydration? It’s simple: Make hydration as important as any other factor in your facility’s safety regimen… make hydration facilities accessible to all and a pleasure to use! You can rest assured that workers forced to use a dirty refillable cooler or garden hose to get a drink will likely not do more than just quench their thirst! The same holds true for office and plant workers, even though their hydration alternatives are usually somewhat better.
The really good news here is that people are more aware of the personal benefits of staying hydrated than ever before. Consider the number of people you encounter every day who carry around bottles of water with them everywhere they go, In the U.S. alone, we consume over 50 billion half liter bottles of drinking water per year! Obviously, bottled water has its own set of cost and environmental concerns, but there are a number of significantly more cost efficient and ecofriendly alternatives to making water accessible to employees and aggressively encouraging their use.
So, go ahead… stay hydrated and stay safe!
References 1 Bursill AE: The restriction of peripheral vision during exposure to hot and humid conditions. Q J Exp Psychol 10 :113 –129,1958 .
2 Cian C, Koulmann N, Barraud P, Raphel C, Jimenez C, Melin B: Influence of variations in body hydration on cognitive function: effect of hyperhydration, heat stress, and exercise-induced dehydration. J Psychophysiology14:29 –36,2000 .
3 Pitts GC, Johnson RE, Consolazio FC: Work in the heat as affected by intake of water, salt and glucose. Am J Physiol 142 :253 –259,1944 .
4 Murray B: Hydration and Physical Performance. J Am Coll Nutr, in press, 2007 and Maughan RJ, Shirreffs SM, Watson P: Exercise, Heat, Hydration, and the Brain. J Am Coll Nutr , in press, 2007 .