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About this tool
Daily fluid target for older adults from the 30 mL/kg rule with a 1,500 mL floor, adjusted for fever, heat and activity, plus medication cautions.
The Senior Hydration Target Calculator sets a daily fluid figure for an older adult from the 30 mL per kilogram of body weight rule used in geriatric nutrition practice, with the 1,500 mL a day minimum that ESPEN treats as the floor for older adults. It then adds roughly 12% per degree of fever, 500 mL for a hot day and 500 mL per hour of sustained activity, and compares the result with the EFSA adequate intake from drinks of 2,000 mL for men and 1,600 mL for women. Medicines that alter fluid balance are flagged for discussion rather than silently added to the total.
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Uses 30 mL/kg but never falls below the 1,500 mL daily minimum, which matters for small or frail older adults.
A clinician-set fluid restriction overrides the calculation instead of competing with it.
Diuretics, SGLT2 inhibitors, lithium, laxatives and anticholinergics are flagged with what each one changes.
A common clinical estimate is 30 mL per kilogram of body weight, with a minimum of about 1,500 mL a day. That is roughly 1,950 mL for a 65 kg adult. EFSA's adequate intake from drinks is 2,000 mL for men and 1,600 mL for women. Anyone on a fluid restriction for heart or kidney disease must follow the figure their doctor sets instead.
Three changes stack up: the thirst signal blunts with age so dryness is felt later, total body water falls as muscle is lost, and the ageing kidney concentrates urine less efficiently so more water is lost. Reduced mobility and a fear of night-time toilet trips also cut intake, and several common medicines increase losses.
Dark or strong-smelling urine, passing urine fewer than four times a day, a dry mouth and new confusion or drowsiness. In older adults, sudden confusion or unusual sleepiness is often the first thing anyone notices, and it warrants a same-day medical assessment rather than just a glass of water.
Yes. Tea, coffee, milk, soup, juice and even water-rich foods such as curd, watermelon and dal all contribute. The mild diuretic effect of caffeine at normal intakes does not cancel out the fluid in the cup. Roughly 20 to 30% of total water intake comes from food, which is why the from-drinks targets are lower than total water figures.
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