- A number of studies have been done over time linking dehydration to lower physical and mental performance. For example, Wasterlund and Chaseling  studied forest workers in a controlled environment, where one group was properly hydrated and the other dehydrated to an extent of about 1% of body weight loss. The measure was the time required to debark and stack 2.4 cubic meters of pulpwood. The result was a 12% decrease in productivity from the dehydrated group.
- There are many more studies that attained comparable results. With respect to mental performance, Gopinthan et al.  studied the effects of dehydration on decision-making and cognitive performance, which could result in a decline in productivity and also could be associated with an increased risk of work-related accidents. In this study, subjects were passively dehydrated to 1, 2, 3 and 4% of body weight with specific testing throughout the decline. The study concluded that visual motor tracking, short-term memory, attention and arithmetic efficiency were all impaired at dehydration levels of 2% of body weight or more. In the extreme, the Gopinthan study also noted a 23% reduction in reaction time when subjects were 4% dehydrated.
- It’s been estimated that up to 80% of the U.S. adult population goes through their normal day in at least a mildly dehydrated state. And, if one reports for work dehydrated, the odds of that circumstance improving during the day aren’t very good.
- When an employee is performing physical work, sweat output can easily outpace water intake, which will lead to dehydration. And, more severe working conditions can accelerate dehydration. Bishop et al.  observed that fully encapsulated protective clothing increased sweat rates up to 2.25 liters per hour. In the simplest of terms, what fluids leave the body must be replaced or dehydration is inevitable.
- Finally, evidence from several studies seems to indicate that dehydration may be linked to job-related accidents by causing “orthostatic intolerance”. Adolph  cited that dehydrated subjects fainted more quickly when subjected to an orthostatic challenge test (a change in body posture). Similarly, Carter et al.  established that at a 3% dehydrated state from heat exposure subjects experienced a significant reduction in cerebral blood flow velocity when changing from a seated to a standing position.
Assessing hydration status
The conventional wisdom of “eight glasses a day”, doesn’t hold water (pun intended) when one considers the wide variety of body sizes, shapes, states of wellness and the level of outside influences to which each individual is subjected daily.
Assessing urine color, although it has limitations, is one of the best methods of superficially monitoring hydration. This obviously personal assessment certainly involves the individual employee’s commitment and best intentions.
Hydration action planning
Improving overall employee hydration is best accomplished through the use of a three-pronged approach including education, assessment, and implementation of best practices of encouraging fluid intake during the work day.
Education – The most critical component is employee involvement. The personal benefits of proper hydration span all facets of a person’s life. The cognitive and performance-based advantages gained from good hydration at work will, obviously, be available after work as well. From an employee’s perspective, proper hydration involves a decision to improve and the determination to make assessing their hydration state and staying hydrated habitual.
Companies should make hydration education an ongoing part of employee communications. Employees should be made aware of the downside of drinking soda and coffee in the interest of hydration. Both usually contain caffeine, which is a diuretic that will act to further dehydrate the body, while the person drinking them may think they are alleviating dehydration. And, any sugar content further taxes the body, due to its processing demand, again serving to dehydrate. These and other pertinent facts should be reinforced consistently through training and visual reminders.
Assessment – The best way to assess hydration status, given the variables of body mass, work routines and other environmental and personal issues, is to monitor urine color. Urine that is clear to light yellow is a reasonable indicator of proper hydration. However, heavy consumption of water to overcome darker color urine can “falsely” lighten subsequent urinations, as it may take up to 24 hours for the body to assimilate sufficient additional fluids to fully rehydrate itself. The key is consistent hydration and consistent assessment; with consistent hydration and consistent assessment, urine color becomes more stable and monitoring becomes much more accurate. Again, this should all be part of the ongoing education program. Local hospitals usually have dieticians or other professionals on staff who will be eager to help build your educational and reminder programs.
Implementation – The critical third facet in the hydration plan is making drinking water very readily accessible and appealing. While plumbing codes mandate the availability of drinking fountains in commercial buildings, they do not cover either maintenance or water quality issues. With respect to maintenance, consider your own personal acceptance of drinking fountains in your workplace. Are the facilities for providing drinking water inviting enough for you to use them regularly? Don’t forget that you are going to be asking employees to use these facilities much more frequently than ever as part of your increased hydration initiative. How does the water taste?
Many companies moved to bottled water over the years. While that approach can certainly encourage hydration, it is both expensive and environmentally insensitive. In the U.S. alone, we use 50 billion small (half liter) bottles of water each year and place between 30 and 40 billion of those containers in landfills. Bottled water may handle the access to acceptable water issue, but it will inevitably create another problem down the line.
Consider upgrading your existing installed drinking fountains with advanced products that encourage use and can become an active part of your hydration reminder program. Chilled water, filtered to remove the chlorine taste, with enhanced low-maintenance features to allay sanitary fears.
Encouraging employee hydration can have significant impact on your company’s overall performance and safety record, as well as the general welfare and health of your staff. It requires a firm commitment on the part of management, complete buy-in from employees who will be asked to alter their personal habits and continuous reinforcement from all involved.
1 Wasterlund DS, Chaseling J, Burstrom L: The effect of fluid consumption on the forest workers’ performance strategy. Appl Ergon 35:29-36, 2004
2 Gopinathan PM, Pichan G, Sharma VM: Role of dehydration in heat stress-induced variations in mental performance. Arch Environ Health 43:15-17, 1988
3 Bishop PA, Pieroni RE, Smith JF, Constable SH: Limitations to heavy work at 21 degrees C of personnel wearing the US Military chemical defense ensemble. Aviat Space Environ Med 62: 216-220, 1991
4 Van Loan M: Age, gender, and fluid balance. In Buskirk ER and Puhl, SM. (eds): Body Fluid Balance: Exercise and Sport. Boca Raton: CRC Press, pp. 215- 230, 1996
5 Carter R 3rd, Cheuvront SN, Vernieuw CR, Sawka MN: Hypohydration and prior heat stress exacerbates decreases in cerebral blood flow velocity during standing. J Appl Physiol 101:1744-1750, 2006