Tag Archives: Hydration

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Short sleepers are more likely to wake up dehydrated

Individuals who only get six hours of sleep per night are at a higher risk of dehydration than those that get eight to nine hours. So, if your schedule really doesn’t permit you to get more sleep, these findings suggest that you ought to drink plenty of water first thing in the morning.

Credit: Pixabay.

Credit: Pixabay.

Researchers at Penn State analyzed sleep duration and hydration status in American and Chinese adults, using data from the National Health and Nutrition Examination Survey and the Chinese Kailuan Study, respectively. For both populations, adults who reported sleeping for six hours or less had significantly more concentrated urine and 16-59 percent higher odds of being inadequately hydrated compared to adults who slept eight hours a night, the authors reported in the journal Sleep.

This is an observational study, so no causal relationship can be established at this point. However, the observed association is significant, which should warrant attention.

According to the researchers, the reason why sleep duration may affect hydration comes down to a hormone called vasopressin. This hormone’s job is to regulate hydration in the body and to prevent you from expelling diluted urine. When we drink alcohol the body sends a signal to the pituitary gland to block the creation of this antidiuretic hormone. Your kidneys then begin sending water directly to your bladder instead of reabsorbing the water into the body for use. As a result, cells do not get properly hydrated and you need to go pee every fifteen minutes.

The hormone is released both during the day and the night. However, its release cycles vary more during the night. People don’t drink water while they sleep, so the body has to minimize water loss to remain sufficiently hydrated — this is why you shouldn’t feel thirsty during the night. Improper vasopressin generation and release, for instance, is also one of the main reasons why children wet their beds.

“Vasopressin is released both more quickly and later on in the sleep cycle,” lead author Asher Rosinger, assistant professor of biobehavioral health at Penn State, said in a statement. “So, if you’re waking up earlier, you might miss that window in which more of the hormone is released, causing a disruption in the body’s hydration.”

Poor hydration can mess with the body’s functions, negatively affecting mood, cognition, or physical performance. When dehydration becomes chronic, individuals risk serious problems such as urinary tract infections and kidney stones.

Rosinger and colleagues recommend people get enough sleep in order to stay hydrated. If that’s just not possible, drink plenty of water in the morning to quickly start replenishing water content in your cells.

Harar Old Man.

Proper hydration helps seniors get the full benefit of exercise and keeps their minds limber

When your hairs start turning gray, the water bottle should be your mainstay — at least while exercising. New research shows that middle-aged and older adults should drink more water to gain the full benefits of exercise.

Harar Old Man.

Image credits Gustavo Jeronimo / Wikimedia.

Few things will ruin your workout quite like dehydration. Even if you power through and keep to your routine despite the cottonmouth, you won’t benefit that much from it: dehydration has been shown to impair exercise performance and brain function in young people. However, the effect of dehydration during exercise for older individuals was poorly studied, and thus poorly understood, as there are some key metabolic differences between these age groups.

“Middle-age and older adults often display a blunted thirst perception, which places them at risk for dehydration and subsequently may reduce the cognitive health-related benefits of exercise,” the authors wrote.

Age slows down our metabolic rate, meaning we need fewer calories. Coupled with the fact that we generally tend not be as physically active as we age, elderly people tend to experience a decrease in appetite too. By eating less food, they get less hydration from solid food sources — humans generally get about half their daily water requirement from solid foods, as well fruit and vegetable juices.

To get a better understanding of how this impacts the health benefits of exercise, the New England-based team of researchers recruited recreational cyclists who took part in a large cycling event on a warm day (78-86°F or 25.5-30°C). The participants’ average age was 55.

The cyclists were asked to go through a “trail-making” executive function test: they had to connect numbered dots on a piece of paper, being graded both on their speed and accuracy. Executive functions are a set of processes that all have to do with managing oneself and one’s resources in order to achieve a goal. They include the ability to plan, focus, remember, and multitask. Exercise has been shown to improve intellectual health, including executive function.

The team also tested the volunteers’ urine before they exercised, and divided them into two groups based on the results — either in the ‘normal hydration’ or the ‘dehydrated’ groups.

Those in the normal hydration group showed a noticeable improvement in completion speed of the trail-making test after cycling (relative to their initial results). The dehydrated group also completed the task more quickly after cycling, but the difference in completion times wasn’t significant, the researchers noted.

“This suggests that older adults should adopt adequate drinking behaviors to reduce cognitive fatigue and potentially enhance the cognitive benefits of regular exercise participation,” the researchers wrote.

The paper “Dehydration impairs executive function task in middle-age and older adults following endurance exercise” was presented on Sunday, April 22, at the American Physiological Society (APS) annual meeting Experimental Biology 2018 in San Diego.