Importance of Hydration for Resilience

Hello everyone Floyd Meyer here I am a Physician Assistant with a Master’s in public health, a degree in molecular biology, and I am currently working in physical medicine and rehabilitation. Today we are continuing our series on Resilience which is the ability to remain well, recover, or even thrive in the face of adversity.

Last week we discussed how important micronutrients are to improving immune resilience. This week we are going to discuss hydration and how adequate water intake is essential for maintaining our overall resilience.

One major component of resilience is our physiologic reserves. Your “physiologic reserve is the potential capacity of a cell, tissue, or organ system to function beyond its basal level in response to alterations in physiologic demands.” (Whitson et al., 2015)

When our bodies are put into a stressful situation whether that be physical stress or mental stress we are forced to overcome that stress or break under the pressure. The difference in outcomes lies in our body’s ability to function beyond its normal level.

For instance, if you were already red-lining your system by doing an extremely hard work out, but then you were put in a situation that you needed to push your body even farther you may not be able to handle this added stress because your reserves have already been depleted.  

This is how I think about hydration and its influence on resilience.

Mild dehydration is extremely common in many different population groups especially those people who are older or those who participate in activities in warm environments. (Maughan, 2003)

According to an article in the journal Nutrition Reviews, “Under relatively mild levels of dehydration, individuals engaging in rigorous physical activity will experience decrements in performance related to reduced endurance, increased fatigue, altered thermoregulatory capability, reduced motivation, and increased perceived effort.” (Popkin et al., 2010)

You don’t need to be extremely dehydrated to see decreases in the body’s ability to handle added stressors. Not only does dehydration affect the physical body, the mind is also directly impacted.

That same review goes on to state that, “Mild levels of dehydration can produce disruptions in mood and cognitive functioning.” They saw significant changes in subjective mood scores including increased fatigue, confusion, and anger. (Popkin et al., 2010)

So not only is being dehydrated directly decreasing performance it is also affecting your perception of tasks making them seem more difficult and annoying. If you perceive a task as more frustrating and confusing it will take more energy to overcome your perception leaving you less energy to focus on other goals. 

Now that we know that mild dehydration can affect our performance both mentally and physically we should ask how does dehydration impact chronic disease risk?

Unfortunately, there is not a good standard for measuring hydration status at a population level and as such the data surrounding the connection between chronic mild dehydration and chronic disease risk is muddy. What we know for sure is that dehydration directly impacts kidney function.

In an article posted in the Annals of Nutrition and Metabolism they state that, “Multiple associations have been reported between fluid intake and kidney and metabolic health outcomes, including chronic kidney disease (CKD), recurrence of kidney stones, and some metabolic markers of hyperglycemia.” They go on to say that individuals who reported the highest intake of plain water had significantly reduced risk of CKD, and was associated with cardiovascular disease and all-cause mortality.  (Perrier, 2017)

According to the journal Nutrition Reviews, “the kidneys function more efficiently in the presence of an abundant water supply.” Without adequate water intake the kidneys will expend a greater amount of energy and incur more wear and tear on their tissues, and this is especially likely to occur when the kidneys are under stress, e.g., when the diet contains excessive amounts of salt or toxic substances that need to be eliminated. “Consequently, drinking a sufficient amount of water helps protect this vital organ.” (Popkin et al., 2010)

This last statement I think really details this idea of hydration, resilience, and physiologic reserve. The kidneys are an amazing organ, and being dehydrated, unless severe, does not completely shut them down. But what this chronic mild dehydration does is increase the amount of stress on the kidneys decreasing their reserves for future stressors like for example getting sick.

By creating an environment where the body is adequately hydrated you will be in the best possible position having the largest physiologic reserves ready for when stressors are encountered.

But what does it take to be sufficiently hydrated?

In general, “intake requirements range from 2.5 to just over 3 L/day in adults under normal conditions, and can reach 6 L/day with high extremes of heat and activity.” (Popkin et al., 2010)

In my time practicing medicine I have had very few patients who have reached theses daily requirements. Most people go off thirst and taste to guide their fluid intake. Unfortunately, according to the Sports Nutrition Handbook, thirst is not a good measure of hydration status.

First because there are so many distractions throughout a person’s day thirst signals can easily be disregarded. Not only that but in order for our thirst signals to be activated some dehydration must already be present.

In order to maintain an optimal level of resilience through adequate hydration I would recommend a baseline intake of 2-3L of water for most adults. Then if you are active, outside in the heat, or otherwise doing tasks that cause you to sweat then add another 1-2 L as needed.

For example, if you are going to be exercising in a gym for about 1 hour and you sweat an average amount you would want to add about 1L of extra water on top of the normal 2-3L baseline.

If you are going to be exercising outside in the summer heat for an extended period of time and you are sweating profusely then you should probably add 2L extra water on top of the normal 2-3L baseline.

The exact amounts of water necessary for you personally may be higher or lower than the above examples, but this should at least give you a good place to start.

So in summary, adequate hydration is necessary for optimal physical and mental performance. Even mild dehydration can lead to disruptions in mood, cognitive functioning, reduced endurance, increased fatigue, and directly impacts kidney function.

In order to maintain resilience we should ingest between 2-3L of water per day in our food and drink. Then if we are engaging in physical activity or spending time in the heat we will need to add subsequent water on top of this baseline level.

I hope that this has been helpful. If you have any questions please leave them in the comments below. If this resonated with you please share with your friends and family and subscribe and follow for more of this content. The time for action is now. Again this is Floyd Meyer. Have a great day!


El-Sharkawy, A. M., Sahota, O., & Lobo, D. N. (2015). Acute and chronic effects of hydration status on health. Nutrition Reviews, 73(suppl 2), 97–109. doi:10.1093/nutrit/nuv038

Kalhoff, H. (2003). Mild dehydration: a risk factor of broncho-pulmonary disorders? European Journal of Clinical Nutrition, 57(S2), S81–S87. doi:10.1038/sj.ejcn.1601906

Karpinski, C., & Rosenbloom, C. (2017). Sports nutrition: a handbook for professionals. Chicago: Academy of Nutrition and Dietetics.

Maughan, R. Impact of mild dehydration on wellness and on exercise performance. Eur J Clin Nutr 57, S19–S23 (2003).

Nuccio, R. P., Barnes, K. A., Carter, J. M., & Baker, L. B. (2017). Fluid Balance in Team Sport Athletes and the Effect of Hypohydration on Cognitive, Technical, and Physical Performance. Sports Medicine, 47(10), 1951–1982. doi:10.1007/s40279-017-0738-7 

Perrier, E. T. (2017). Shifting Focus: From Hydration for Performance to Hydration for Health. Annals of Nutrition and Metabolism, 70(1), 4–12. doi:10.1159/000462996 

Popkin, B. M., D’Anci, K. E., & Rosenberg, I. H. (2010). Water, hydration, and health. Nutrition Reviews, 68(8), 439–458. doi:10.1111/j.1753-4887.2010.00304.x 

Roussel R, Fezeu L, Bouby N, Balkau B, Lantieri O, Alhenc-Gelas F, Marre M, Bankir L: Low water intake and risk for new-onset hyperglycemia. Diabetes Care 2011;34:2551– 2554

Whitson, H. E., Duan-Porter, W., Schmader, K. E., Morey, M. C., Cohen, H. J., & Colón-Emeric, C. S. (2015). Physical Resilience in Older Adults: Systematic Review and Development of an Emerging Construct. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 71(4), 489–495. doi:10.1093/gerona/glv202 


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