Rehydration Solutions: Use During COVID-19 Pandemic

By: James Mayo & Blanca Lizaola-Mayo MD


Water is a critical nutrient. All known life forms depend on water; it is considered as one of the best solvents for inorganic matter because it exhibits the highest known polarity. Besides, it also exhibits extremely high heat capacity, making it a superior heat regulator. In the human body, water’s role as a solvent – where it dissolves ionic compounds to create solutions that allow transport of metal ions across molecular membranes – is the one with the most significant consequences for our health and well-being.

During day-to-day activities, a person typically loses about two liters of water through breathing, sweat, urine, and bowel movements. This is increased significantly during exercise when fluid loss can be up to two liters per hour. In addition to water, sweat contains different metal ions: mostly sodium (range 10-70 mEq/L) and chloride (range 5-60 mEq/L) (Baker, 2015). During the COVID19 pandemic, hydration is imperative for well-being. In addition, staying active is critical for both physical and mental health. Physical activity helps our mind and body in many ways (VicHealth, 2020;, 2020). But it is essential to be careful as increased physical activity can lead to dehydration if one is not adequately prepared.

Downloadable Report → Rehydration Solutions: Use During COVID-19 Pandemic

Physical exertion places a strain on our immune system. At a higher level of physical exertion, our immune system undergoes significant changes: an increase in stress hormones and cytokine concentrations, changes in body temperature, an increase in blood flow, and dehydration (Nieman, 2007). These changes create a window of 3 to 72 hours when the immune system is impaired, potentially allowing pathogens to gain a foothold in the human body. Fluid replacement is the most effective countermeasure against exertion-related immune perturbations. In addition, a study of thermal dehydration has shown that the changes to hematologic parameters during thermal exposure without exercise are remarkably similar to those during physical exercise (Ohira et al., 1981). Dehydration has the same effect on the human body, regardless of the level of physical activity, and it should always be treated with caution.

Many essential workers have had a significant increase in their workload during the pandemic. The use of personal protective equipment requires more exertion to complete any task, and its relative scarcity during the pandemic means that people spend more time using it than they usually  would. COVID-19 patients commonly exhibit fever, diarrhea, and vomiting as symptoms of the disease. If left unattended, it can lead to severe dehydration, exacerbating their symptoms and making their recovery more difficult.

The issue of dehydration is much more common and dangerous, especially when considering the risks that front line medical workers are facing. Therefore, the proper use of rehydration tools, while seemingly small, can make a big difference: it can help front line medical workers, and their patients fight the disease and help everyone else stay healthy during these challenging times.

Oral rehydration solutions (ORS) are specialized formulations, usually in the form of a powder which contains a mixture of essential salts and sugar that are dissolved in water to create a drink that facilitates faster absorption of water in the human body. Their efficacy is based on the ability of sugar to stimulate sodium and fluid absorption in the small intestine via a cyclic AMPindependent process (Binder et al., 2014). The addition of zinc was found to significantly reduce the duration and severity of diarrheal episodes and the likelihood of subsequent infections for 2-3 months (Khan et al., 2011).

ORS was developed in the 1970s to treat severe dehydration resulting from severe diarrhea without the logistical needs of intravenous hydration using sterile solutions. There have been several significant modifications to ORS since, to improve its efficacy and effectiveness. Original formulations were iso-osmolar: they had the same osmolarity of 311 mOsm/kg H2O as the fluid in the human cells. However, several studies have shown that hypo-osmolar food-based formulations performed better in clinical trials (Gore et al., 1992). It was subsequently determined that hypo-osmolar glucose-based formulations also have superior performance and that this was due to lower osmolarity of these formulations (Duggan et al., 2004). Since then, reduced osmolarity formulations have been adopted by many countries as the standard ORS formulations (Walker et al., 2009).

While ORS has been well established for treating dehydration caused by diarrhea, especially in children, it has not been widely adopted to treat dehydration caused by other medical conditions. Even though ORS is not a drug, it is inexpensive and is ideal for common usage to treat conditions  before drugs are employed. One of the reasons may be that ORS does not alleviate the symptoms of the underlying illness: reduce diarrhea, for instance, but corrects acute dehydration. There is a lack of awareness about the existence of ORS and its ability to prevent dehydration in a variety of conditions. ORS may be used as a preventive tool to avoid dehydration.