Water vs. Electrolytes: What’s Better for Hot Work?

Both employers and employees play pivotal roles in preventing heat-related illnesses through effective hydration practices. Working in the heat without proper hydration is a key contributor to heat stress and heat-related illnesses. These ailments not only affect productivity, but they can also be life-threatening (i.e. heat stroke). As global temperatures continue to climb, understanding the ins and outs of proper hydration is critical for health and safety while on the job.

We’re here to address a frequently asked question and provide hydration best practices for working in the heat. So, here it is: which is better for working in the heat—water or electrolyte drinks?

Several studies have examined when electrolyte drinks are more beneficial than water during work or exercise in hot conditions. These studies suggest that electrolyte beverages can be particularly advantageous in specific scenarios involving prolonged physical activity and significant fluid loss. However, water is generally sufficient for hydration in lightwork scenarios.

Key Findings from Research

1. Enhanced Muscle Performance: A study involving endurance-trained cyclists exercising in a hot, dry environment found that consuming carbohydrate-electrolyte drinks (like Gatorade and Powerade) during prolonged cycling preserved leg muscle force better than water or no hydration. The study indicated that the sodium content in these drinks played a crucial role in maintaining muscle performance.
2. Improved Hydration and Recovery: Research comparing various hydration beverages after exercise-induced dehydration showed that a carbohydrate-electrolyte solution was more effective in restoring fluid and electrolyte balance than mineral water or other common drinks. Participants who consumed the electrolyte solution returned to their pre-exercise hydration status more effectively.
3. Delayed Onset of Muscle Cramps: In a controlled trial, participants exercising in a hot environment experienced a longer duration before the onset of exercise-associated muscle cramps when consuming a carbohydrate-electrolyte beverage compared to no hydration. This suggests that electrolyte drinks can help delay muscle fatigue and cramps during prolonged activity in the heat.
4. Maintained Plasma Volume During Energy Restriction: A study examining the effects of electrolyte supplementation during severe energy restriction found that participants who consumed sodium and potassium supplements maintained plasma volume and had better exercise capacity in the heat compared to those who did not receive electrolyte supplementation.

When to Choose Electrolyte Drinks Over Water

Electrolyte beverages are particularly beneficial in the following situations:

• Prolonged Physical Activity: Engaging in extended periods of exercise or labor, especially in hot conditions, where significant sweating occurs.
• High Sweat Rates: Individuals who naturally sweat more or are working in environments that induce heavy sweating. This also applies in a heat wave or heat dome, when temperatures are abnormally high and cause excessive sweating.
• Energy Restriction: During periods of limited caloric intake, such as fasting or dieting, where electrolyte balance may be compromised.
• Post-Work Recovery Needs: After working in the heat, electrolyte drinks help with recovery to replenish lost electrolytes and fluids more efficiently.

For routine hydration during light activities or in cooler environments, water remains sufficient. However, in the scenarios outlined above, incorporating electrolyte drinks can help maintain performance, prevent dehydration-related issues, and support overall health.

General Findings

Water Suffices for Most Light Work Situations: For lighter activity levels, drinking water is adequate, especially when combined with a balanced diet.

Electrolyte Drinks for Intense Activity: During prolonged or strenuous work in the heat, the body loses not only water but also essential electrolytes. In such cases, supplementing with electrolyte drinks can help replenish lost minerals. However, moderation is key, as excessive consumption can lead to imbalances.

The National Institute for Occupational Safety and Health (NIOSH) advises consuming 8 ounces of water every 15–20 minutes during heat exposure. Consistent hydration helps regulate the body's metabolic functions and manage heat stress effectively.

Pre-Hydration is Beneficial: Starting the workday with a couple of glasses of water can help maintain hydration levels in the heat. Waiting until thirst sets in may indicate that dehydration has already begun. Starting the workday well-hydrated and replenishing fluids after work can reduce bodily stress and aid recovery.

Avoid Certain Beverages: Sugary, caffeinated, and alcoholic drinks can exacerbate dehydration and should be limited while working in the heat.

Sodium is a Benefit: While salt is generally viewed as a common “dehydrator”, it is highly beneficial when working in the heat. Numerous studies have proven that sodium helps retain water in the body, maintain blood volume, improve exercise capacity, and prevent dehydration in hot conditions. In a study, participants who received sodium supplementation during energy restriction had an exercise capacity of 67.0 minutes, compared to 56.5 minutes in those without supplementation.

Adequate sodium intake supports a stable internal body temperature (thermoregulation) by maintaining blood volume, which is essential for heat dissipation. During prolonged work in the heat, sodium reduces the strain on your heart (cardiovascular strain). It also helps prevent hyponatremia, a sometimes lethal condition that is covered in the following section.

Beware of Overhydration: While staying hydrated is vital, excessive water intake—specifically more than 48 ounces in an hour—can lead to hyponatremia or “water intoxication”. This condition results from blood sodium levels dropping dangerously low. This can cause symptoms like nausea, confusion, seizures, and in severe cases, coma or death. Consuming salty snacks can help maintain electrolyte balance.

Individual Needs Vary: People with certain medical conditions or those on specific medications should consult healthcare providers for personalized hydration advice.

Recognizing Dehydration Signs: Symptoms such as headaches, fatigue, dizziness, flushed skin, muscle cramps, and dark-colored urine can signal dehydration. Early detection is crucial to prevent more severe heat-related conditions.

Employer Responsibilities

• Accessible Water Supply: The Occupational Safety and Health Administration (OSHA) mandates that employers provide cool water (ideally between 50°F and 60°F) in easily accessible locations close to work areas. This encourages regular consumption and helps maintain hydration levels.
• Monitoring and Maintenance: Employers should estimate the necessary water volume for their workforce and assign personnel to monitor and maintain water supplies, ensuring availability throughout the workday.

Maintaining proper hydration is a shared responsibility. Employers must provide adequate resources and education, while workers should adopt proactive hydration habits. Proper hydration in hot weather involves drinking water regularly, recognizing when electrolyte supplementation is necessary, and avoiding overconsumption of fluids. Tailoring hydration strategies to individual needs and activities ensures optimal health and performance during heat exposure.

Sources

Osterberg, K. L., Pallardy, S. E., Johnson, R. J., & Horswill, C. A. (2010). Carbohydrate and electrolyte beverage effects on endurance performance and body temperature. International Journal of Sport Nutrition and Exercise Metabolism, 20(6), 546–554. https://doi.org/10.1123/ijsnem.20.6.546