Why Dehydration Is Common in Older Adults
The first, and perhaps most perplexing, cause of dehydration in older adults is a lack of thirst. During the aging process, thirst sensation naturally decreases, says Dr. Audrey Chun, vice chair of geriatric and palliative medicine outpatient services in the Mount Sinai Health System and director of Coffey Geriatrics at The Martha Stewart Center for Living at Mount Sinai Hospital.
While the mechanisms are not clear-cut, thirst levels in adults older than 65 are commonly far lower than indicative of the body's actual fluid needs. Because of this decreased thirst sensation, many adults do not drink as much as they did in their younger days, says Dr. Sanjay Kurani, medical director of inpatient medicine at Santa Clara Valley Medical Center in San Jose, California.
Plus, throughout the aging process, the kidneys naturally lose some of their ability to conserve water and concentrate urine, leading to greater fluid losses through urination. A decline in muscle mass, referred to as sarcopenia, can also reduce how much water the body can store, as muscle functions as a significant holding area for water molecules. One out of three adults age 60 and older suffers from severe muscle loss, according to a 2014 review published in Age and Ageing.
此外，在整个衰老过程中，肾脏储水和浓缩尿的能力会逐渐地自然丧失，导致排尿时流失更多的水分。肌肉质量的下降，称为肌肉减少症，也会降低身体的储水量，因为肌肉是保持水分子的重要部位。2014年，Age and Ageing期刊上发表的一篇综述表示：60岁及以上的老年人中，三分之一的人患有严重的肌肉损失。
Age-related health conditions can further predispose older adults to dehydration. Undiagnosed or uncontrolled Type 2 diabetes can increase urination, while urinary incontinence and resulting anxieties can cause a reduction in fluid consumption. Reduced mobility can cut down on how often people are willing to make trips to get water and use the restroom, Kurani says. People with Alzheimer's disease or dementia are also at an increased risk of not drinking enough water, according to 2018 research published in Nutrients.
What's more, commonly used over-the-counter and prescription medication can contribute to fluid losses as well. Blood pressure medications such as diuretics are commonly associated with dehydration in the elderly, Kurani says. Antihistamines and laxatives are also medications that can result in dehydration.