A study on endurance-trained cyclists revealed that dehydration significantly impairs cardiovascular function during exercise, especially when combined with hyperthermia. While hyperthermia or dehydration alone reduced stroke volume by 7–8%, the combination led to a 20% reduction in stroke volume and a 13% drop in cardiac output, causing greater cardiovascular strain. Restoring blood volume reversed the effects of dehydration alone, underscoring the critical role of hydration in maintaining cardiovascular stability during intense exercise in hot conditions.
A systematic review of studies found that producing less than 900 mL of urine per day increases the risk of kidney stones, with a minimum safe urine output of 1.6 liters per day for those who've had stones before. The most effective beverages for prevention include low-calcium water, citrus juices, and blackcurrant juice, while cranberry and plum juices have less favorable effects. Drinking an additional 1.3 liters of fluid daily can help achieve protective urine levels and reduce kidney stone risk.
The study highlights the significant impact of dehydration on sustained attention in middle-to-older-aged adults, who are more vulnerable to dehydration due to age-related changes in thirst perception. While dehydration did not impair memory or problem-solving, it made tasks requiring prolonged focus much harder. The findings emphasize the importance of staying hydrated to maintain mental sharpness, particularly for older adults.
Dehydration impairs concentration, short-term memory, and overall mood.
Dehydration is one of the factors that can influence the onset or exacerbation of headaches. Although the mechanism by which dehydration affects headaches is not fully understood, data suggest that this condition can impact the pain threshold, intensifying pain and increasing the risk of a range of disorders associated with headaches.