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  • Brian Bender, PhD

Hydration Safety in the Workplace

Updated: May 2

It's hard to overstate the importance of hydration for workplace safety.

A review of 33 studies and over 13,000 workers identified 35% of these employees experience occupational heat stress after their shift, and a a review of 11 studies and over 8,000 workers showed that 30% of these employees reported a loss in productivity due to heat [1]. A further 15% of over 20,000 workers studies presented with kidney disease or acute kidney injury due to prolonged heat exposure.

In fact, BLS statistics show environmental heat stress results in a number of fatalities every year in the US. Yet, according to the National Athletic Trainers' Association, exertional heat stroke (EHS), the most life‐threatening heat‐related illness, is considered 100% survivable when appropriate procedures are in place [2].

Workplace Hydration

Over 13 million individuals work in extreme heat every day in the US alone [3]. The most extreme need arises in workers who spend prolonged time under high heat and humidity, heavy clothing, and high exertional activity. This includes workers in construction, agriculture, firefighters, manufacturing, and other related jobs.

Monitoring hydration in the workplace and imposing proper hydration practices are the best ways to identify at-risk individuals and prevent hydration-related illness.

Although differences in approaches exist, there are several workplace safety guidelines for preventing and managing heat stress:

  • OSHA [4]

  • ACGIH [5]

  • NIOSH [6]

Despite differences, following any of these guidelines improves results, and the majority of heat-related injuries occur when these plans are not in place and thresholds for heat exposure are exceeded.

Studies have shown that employers' primary concerns towards implementing heat-safety procedures are, in order of importance, cost and feasibility [7]. Loss in productivity related to implementing these procedures was also a concern, despite the irony of well-documented hydration-related losses in productivity that occur during frequent heat stress.

How to Maintain Hydration Safety in the Workplace

A recent consensus developed by a panel of 51 experts in occupational health and safety created a suite of recommendations for maintaining hydration safety in the workplace while attempting to meet employers' perceptions of cost, feasibility, and productivity [3].

Eight categories were identified as areas requiring attention for preventing heat and hydration-related illness with specific strategies for each. The following are condensed, high-level notes, and we recommend diving into the consensus report for more details.

  • Heat hygiene

    • Heat education and worker monitoring prior to shifts.

  • Hydration

    • Hydration status monitoring and access to fluids and fluid replacement practices.

  • Heat acclimatization (HA)

    • Gradual introduction of workers to high-heat work environments.

  • Environmental monitoring

    • Environmental heat and humidity monitoring to dictate worker break frequency.

  • Physiological monitoring

    • Devices to monitor physiological health markers should be used when available.

  • Body cooling

    • Access to breaks with body temperature cooling systems.

  • Textiles and personal protective gear

    • Proper PPE that is work appropriate and minimizes heat stress should be prioritized.

  • Emergency procedures and EAPs

    • Emergency should be addressable on-site and this information should be communicated to employees.

Monitoring hydration status at the start, during, and end of work shifts is most easily accomplished using urine specific gravity measurements, as is done in occupational health studies [8].

Typically, when urine specific gravity measurements greater than 1.020 indicate a warning and mild dehydration, while urine specific gravity measurements greater than 1.030 indicate dehydration. The goal for proper hydration is often put at 1.015 or below. Monitoring of these categories before, during, and after work shifts helps plan preventive measures and fluid replacement needs in real-time.

Office Workplace Hydration

Workers exposed to high heat and humidity and/or physically demanding tasks are of significantly higher risk of heat related illness. However, this is not the only negative workplace consequence of dehydration.

Dehydration impairs mood, energy levels, and productivity via losses in cognitive function. A meta-analysis of dehydration demonstrated a statistically significant impairment to cognitive function, including attention, executive function, and motor coordination [9]. Another study showed a decline in ability to perform mathematical operations [10].

So whether your employees work in the heat or in the office, it's important to consider proper monitoring and access to processes and supplies that maintain employee hydration for safety and productivity, alike. Having good water bottles on hand is useful, as is water stations and/or sports drinks with electrolytes when sweating is expected to last hours on end.


  1. Flouris AD, Dinas PC, Ioannou LG, Nybo L, Havenith G, Kenny GP, Kjellstrom T. Workers' health and productivity under occupational heat strain: a systematic review and meta-analysis. Lancet Planet Health. 2018 Dec;2(12):e521-e531. doi: 10.1016/S2542-5196(18)30237-7. PMID: 30526938.

  2. Casa DJ, DeMartini JK, Bergeron MF, et al. National Athletic Trainers' Association Position Statement: Exertional Heat Illnesses [published correction appears in J Athl Train. 2017 Apr;52(4):401]. J Athl Train. 2015;50(9):986-1000. doi:10.4085/1062-6050-50.9.07.

  3. Morrissey MC, Casa DJ, Brewer GJ, Adams WM, Hosokawa Y, Benjamin CL, Grundstein AJ, Hostler D, McDermott BP, McQuerry ML, Stearns RL, Filep EM, DeGroot DW, Fulcher J, Flouris AD, Huggins RA, Jacklitsch BL, Jardine JF, Lopez RM, McCarthy RB, Pitisladis Y, Pryor RR, Schlader ZJ, Smith CJ, Smith DL, Spector JT, Vanos JK, Williams WJ, Vargas NT, Yeargin SW. Heat Safety in the Workplace: Modified Delphi Consensus to Establish Strategies and Resources to Protect the US Workers. Geohealth. 2021 Aug 1;5(8):e2021GH000443. doi: 10.1029/2021GH000443. PMID: 34471788; PMCID: PMC8388206.

  4. https://www.osha.gov/heat

  5. American Conference of Governmental Industrial Hygienists. "Threshold limit values for chemical substances and physical agents and biological exposure indices." American Conference of Governmental Industrial Hygienists, 1995.

  6. NIOSH . (2016). Criteria for a recommended standard: Occupational exposure to heat and hot environments.

  7. Nathan B. Morris, Miriam Levi, Marco Morabito, Alessandro Messeri, Leonidas G. Ioannou, Andreas D. Flouris, George Samoutis, Tjaša Pogačar, Lučka Kajfež Bogataj, Jacob F. Piil & Lars Nybo (2021) Health vs. wealth: Employer, employee and policy-maker perspectives on occupational heat stress across multiple European industries, Temperature, 8:3, 284-301, DOI: 10.1080/23328940.2020.1852049.

  8. Brake DJ, Bates GP. Fluid losses and hydration status of industrial workers under thermal stress working extended shifts. Occup Environ Med. 2003 Feb;60(2):90-6. doi: 10.1136/oem.60.2.90. PMID: 12554834; PMCID: PMC1740457.

  9. Wittbrodt MT, Millard-Stafford M. Dehydration Impairs Cognitive Performance: A Meta-analysis. Med Sci Sports Exerc. 2018 Nov;50(11):2360-2368. doi: 10.1249/MSS.0000000000001682. PMID: 29933347.

  10. Piil JF, Lundbye-Jensen J, Christiansen L, et al. High prevalence of hypohydration in occupations with heat stress-Perspectives for performance in combined cognitive and motor tasks. PLoS One. 2018;13(10):e0205321. Published 2018 Oct 24. doi:10.1371/journal.pone.0205321.


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