There are a number of challenges in trying to link chronic dehydration and fluid consumption to various diseases and health outcomes:-
Only a limited number of good studies have been conducted to date. More long-term studies are needed. Larger patient numbers need to be included in future studies.
There are difficulties in assessing patient daily fluid intake and compliance is difficult to monitor. Hydration status constantly changes and hydration can be difficult to measure in some patients especially when daily fluid requirements vary widely from patient to patient.
The diseases that can be complicated or worsened by dehydration are multi-factorial and there are many differences among these diseases. 1
There is, however, increasing evidence that even mild dehydration can play a role in the development of various morbidities (diseases) or conditions. The medical evidence for good hydration shows that it can assist in preventing or treating ailments such as:
- Pressure ulcers – Dehydration is a known risk factor for PU development because of its effect on blood volume and circulation and skin turgor and has been shown to be associated with an increased risk of developing pressure ulcers in 42% of residents in long-term care facilities, home care patients, and elderly patients.2
- Wound healing – Fluid intake to correct impaired hydration, increases levels of tissue oxygen and enhances ulcer healing.3
- Constipation – Studies have confirmed the recommendation to simply increase intake of fluids such as water to prevent constipation.4
- Urinary infections – Urinary tract infections result from a bacterial contamination of the genitourinary tract . They are highly prevalent in both men and women of all age groups, but their frequency is about 50 times higher in adult women. More than half (50–60%) present with at least one UTI at some stage during their lives. Increasing fluid intake and thereby increasing diuresis (the production of urine) has a diluting effect on contaminating bacteria and virulence factors. Secondly, consecutive to increased diuresis, is the flushing effect that occurs with each void, washing out contaminants and cleaning the epithelia. Also, increasing the frequency of voiding has a shrinking effect on the bladder, effectively reducing the available surface area on which bacteria can thrive.5
- Chronic kidney disease – CKD is an inevitably progressive, serious condition associated with impaired quality of life and early mortality, and its prevalence is increasing constantly. CKD is more common among women, men with CKD are 50% more likely than women to progress to end-stage renal disease (ESRD), defined as kidney failure requiring dialysis or transplantation. 44% of people with ESRD have a primary diagnosis of diabetes and 28% of hypertension. Some studies have suggested that increased fluid intake/urine output is associated with a delay in the onset or progression of CKD.6
- Kidney stones – It is predicted that, based on the effects of global warming, the percentage of people living in areas designated as high risk for kidney stone formation would increase from 40% in 2000 to 56% by 2050, and up to 70% by 2095. This would result in a significant “climate-related” increase in kidney stone events.14 Drinking sufficient levels of fluid on a daily basis is an important part of kidney health. Dehydration, especially chronic dehydration, results in the production of urine which has a higher concentration of minerals and waste products. This can lead to the formation of crystals which can affect kidney function and contribute to certain kidney diseases, such as kidney stones. By moderately increasing water intake, to around two litres per day, you may reduce the risk of decline in kidney function 7
- Stokes – Stroke conditions worsened or stayed the same in 42 percent of dehydrated patients, compared to only 17 percent of hydrated patients. Dehydrated stroke patients also had about a four times higher risk of their conditions worsening than hydrated patients.8
- Low blood pressure – Even mild cases of dehydration can cause low blood pressure. Patients with mild dehydration may experience only thirst and dry mouth. Moderate dehydration may cause orthostatic hypotension – a form of low blood pressure in which a person’s blood pressure falls when suddenly standing up or stretching, and severe dehydration (hypovolemia) can lead to shock, kidney failure, confusion, acidosis, coma, and even death.9
- Diabetes – Hypernatremia dehydration is the most devastating type of dehydration because it can result in severe neurological damage from haemorrhage. Normally, an increased osmolality results in water conservation. This does not occur in central Diabetes Insipidus due to a malfunctioning hypothalamus. In hypernatremic dehydration, extracellular osmolality increases and water moves ou of the brain cells. This movement of water causes brain cells to shrink and the blood vessels tear as the brain is pulled away from the skull and the meninges. The tearing of blood vessels results in haemorrhaging and potential for thrombus formation.10
- Cognitive impairment – Delirium is a common manifestation of dehydration that clearly reflects the global impact of dehydration on cerebral function. However, the three areas of the brain most vulnerable to the effects of dehydration are the reticular activating system, which subserves attention and wakefulness; the autonomic structures that regulate psychomotor and regulatory functions; and the cortical and mid-brain structures that are responsible for thought, memory and erception.11
- Dizziness – Dizziness, vertigo or light headedness can occur simply by changing positions, or moving your head or it can occur at the time of or during strenuous exercise.
- Xerostomia – also known as “dry mouth,” is a common but frequently overlooked condition that is typically associated with salivary gland hypofunction. It is estimated that 12-47% of the elderly and 10-19.3% of people in their early 30’s have been suffering from dry mouth. Whilst dehydration may not be the single cause of this condition it can certainly aggravate or worsen the condition.12
- Skin conditions – once the body becomes dehydrated and the skin dries out there is a dysfunction in the skin barrier with an increase in water loss from the body and, subsequently, increased penetration of harmful substances from the environment. This causes the development of sensitization and initiates immune responses resulting in the inflammation of the skin. Skin barrier function depends on several factors including the level of hydration, cellular properties of corneocytes (skin cells), association of these cells in the stratum corneum and speed of changes (turnover) of these cells, amount and composition of intercellular lipids (oils), and skin surface pH (6-20). Water content of the stratum corneum and surface lipids form a balance, which is very important for the function and appearance of the skin, any disturbance of this balance leads to clinical manifestations in the form of dryness and pruritus (itch).13
Recommended daily fluid intake
Approximate adequate daily intakes of fluids (including plain water, milk and other drinks) in litres per day include:
- infants 0–6 months – 0.7 (from breastmilk or formula)
- infants 7–12 months – 0.9 (from breastmilk, formula and other foods and drinks)
- children 1–3 years – 1.0 (about 4 cups)
- children 4–8 years – 1.2 (about 5 cups)
- girls 9–13 years – 1.4 (about 5-6 cups)
- boys 9–13 years – 1.6 (about 6 cups)
- girls 14–18 years – 1.6 (about 6 cups)
- boys 14–18 years – 1.9 (about 7-8 cups)
- Adult women – 2.1 (about 8 cups)
- Adult men – 2.6 (about 10 cups).
These adequate intakes include all fluids, but it is preferable that the majority of intake is from plain water (except for infants where fluid intake is met by breastmilk or infant formula).
Sedentary people, people in cold environments, or people who eat a lot of high-water content foods (such as fruits and vegetables) may need less water. 14
Those working in heated environments or who do heavy work and sports players may also need to increase their water intake.
Care should be taken not to overhydrate.
Also read our blog “HEALTHY SKIN and WATER INTAKE – PART 1”
- Armstrong LE. Challenges of linking chronic dehydration and fluid consumption to health outcomes. J Amer Coll Nutr 70(11): S121-S127, 2012.
- Horn Sd. Et al.; The National Pressure Ulcer Long-Term Care Study: Pressure Ulcer Development in Long-Term Care Residents; Journal of the American Geriatrics Society
- Stotts NA, Hopf HW. The link between tissue oxygen and hydration in nursing home residents with pressure ulcers: preliminary data. Journal of Wound, Ostomy & Continence Nursing 2003;30:184-90
- Arnaud MJ.; Mild dehydration: a risk factor of constipation?; European Journal of Clinical Nutrition (2003) 57, Suppl 2, S88–S95
- Lotan Y. et al.; Impact of fluid intake in the prevention of urinary system diseases: a brief review; Curr Opin Nephrol Hypertens 2013, 22 (Suppl 1):S1–S10
- Romero V. et al.; Kidney Stones: A Global Picture of Prevalence, Incidence, and Associated Risk Factors; Rev Urol. 2010 Spring-Summer; 12(2-3): e86–e96.
- HYDRATION AND KIDNEY HEALTH; Natural Hydration Council UK:http://www.naturalhydrationcouncil.org.uk/wp-content/uploads/2015/03/NHC_hydration_and_kidney_health_FINAL.pdf
- Bahouth MN. et al.; A Prospective Study of the Effect of Dehydration on Stroke Severity and Short Term Outcome; Abstract T MP86:2015; International Stroke Conference Moderated Poster Abstracts – Session Title: In-hospital Treatment Moderated Poster Tour:
- Manouchehr Saljoughian; Hypotension: A Clinical Care Review; US Pharm. 2014;39(2):2-4
- Hospital Hydration Best Practice Toolkit The health and economic benefits of providing water; https://www2.rcn.org.uk/__data/assets/pdf_file/0003/70374/Hydration_Toolkit_-_Entire_and_In_Order.pdf
- Hudson MJ.; Complications of Diabetes Insipidus: The Significance of Headache; Pediatric Nursing
- Wilson MG. and Morley JE.; Impaired cognitive function and mental performance in mild dehydration; European Journal of Clinical Nutrition (2003) 57, Suppl 2, S24–S29
- Mortazavi, H et al. “Xerostomia Due to Systemic Disease: A Review of 20 Conditions and Mechanisms.”Annals of Medical and Health Sciences Research 4 (2014): 503–510. PMC. Web. 4 Aug. 2016.
- Knor T. et al.; Stratum Corneum Hydration and Skin Surface pH in Patients with Atopic Dermatitis; Acta Dermatovenerol Croat 2011;19(4):242-247