Impaired cognitive function and mental performance in mild dehydration

Abstract

Dehydration is a reliable predictor of impaired cognitive status. Objective data, using tests of cortical function, support the deterioration of mental performance in mildly dehydrated younger adults. Dehydration frequently results in delirium as a manifestation of cognitive dysfunction. Although, the occurrence of delirium suggests transient acute global cerebral dysfunction, cognitive impairment may not be completely reversible. Animal studies have identified neuronal mitochondrial damage and glutamate hypertransmission in dehydrated rats. Additional studies have identified an increase in cerebral nicotinamide adenine dinucleotide phosphate-diaphorase activity (nitric oxide synthase, NOS) with dehydration. Available evidence also implicates NOS as a neurotransmitter in long-term potentiation, rendering this a critical enzyme in facilitating learning and memory. With ageing, a reduction of NOS activity has been identified in the cortex and striatum of rats. The reduction of NOs synthase activity that occurs with ageing may blunt the rise that occurs with dehydration, and possibly interfere with memory processing and cognitive function. Dehydration has been shown to be a reliable predictor of increasing frailty, deteriorating mental performance and poor quality of life. Intervention models directed toward improving outcomes in dehydration must incorporate strategies to enhance prompt recognition of cognitive dysfunction.

A study of fluid intake from beverages in a sample of healthy French children, adolescents and adults

“…It is interesting to note that antihypertensive medication is currently prescribed against these very same hormones (Deedwania, 2007;Nesbitt, 2007). In 2002, a meeting was organized in Dortmund to study the physiological effects of mild dehydration, yet the majority of presentations showed the benefits of increased consumption of fluid, be it at the level of cognition (Wilson and Morley, 2003), exercise performance (Maughan, 2003), urolithiasis Beverage intake in the French F Bellisle et al (Siener and Hesse, 2003), urinary tract infection (Beetz, 2003), dental disease (Smith and Shaw, 2003), constipation (Arnaud, 2003) or even broncho-pulmonary infection (Kalhoff, 2003). Such reports are the outcome of scientific studies, rather than 'urban myths found on the Internet' (Negoianu and Goldfarb, 2008).…”

Military nutrition: maintaining health and rebuilding injured tissue

“…In critical illness, it is recommended that daily energy intake is increased to match increased demands to the order of 20 -30 kcal kg 21 body mass [47,58,101]. Objective evidence demonstrating the benefit of matching energy demands with supply is lacking [105]; however, there are harmful consequences associated with over-and underfeeding [55,58,106].…”

“…inability to carry out physical tasks, poor concentration and decreased vigilance) [21,22]. The long-term effects of both macro-and micro-nutrient imbalances include increased risk of vitamin and mineral deficiencies (potentially predisposing some individuals to an increased risk of stress fractures and rickets), obesity, hypertension, coronary heart disease, diabetes, osteoporosis and kidney failure.…”

Frailty and polypharmacy

“…Dehydration is common in older persons and is often made worse by inappropriate use of diuretics to treat pedal edema (46). Dehydration is associated with frailty, falls, syncope, poor cognition, disability and mortality (47)(48)(49)(50)(51).…”