Older Men Need to Hydrate Even When They Are Not Thirsty

A study in the Journal of Physiology examined the effects of dehydration on older adults, reports Medical News Today . The researchers determined that older adults may not feel as thirsty as young people and ought to hydrate when they work or exercise and when the weather is hot. Without sufficient hydration, dehydration in older adults may persist and rise to hazardous levels. Scientists have suggested that older adults feel less thirsty because of a reduced ability to detect and respond to the level of salt in their blood. Ten younger men (18 to 30 years) and 10 older men (54 to 67 years) underwent exercise heat stress tests. At the start of each session, participants received an intravenous saline solution to increase blood osmolality before entering a heated, whole-body direct-air calorimeter for 60 minutes of stationary cycling. An increase in blood salinity in older men was found not to trigger the body's responses to dehydration as it did in the younger participants. Since the researchers investigated the effects of blood osmolality in physically active participants without any known chronic conditions, it is uncertain whether or not the same finding would apply to older adults with common age-related conditions like type 2 diabetes.