Dehydration can affect your brain, make it tough to perform simple tasks

Dehydration,Health,Wellness

According to a recent study, dehydration alters the human brain shape and activity and even slackens task performance. A Georgia Institute of Technology study suggests that when dehydration strikes, part of the brain can swell, neural signalling can intensify, and doing monotonous tasks can get harder.

The researchers also found that even without dehydration, exertion and heat put a dent in test subjects’ performance, but water loss made the dent about twice as deep. “We wanted to tease out whether exercise and heat stress alone have an impact on your cognitive function and study the effect of dehydration on top of that,” said Mindy Millard-Stafford, the study’s principal investigator.

In the experiments, when participants exercised, sweated and drank water, fluid-filled spaces called ventricles in the centre of their brains contracted. But with exertion plus dehydration, the ventricles did the opposite; they expanded. Functional magnetic resonance imaging (fMRI) revealed the differences. Oddly, the ventricle expansion in dehydrated test subjects may not have had much to do with their deeper slumps in task performance.

“The structural changes were remarkably consistent across individuals,” said Millard-Stafford. “But performance differences in the tasks could not be explained by changes in the size of those brain areas.”

“The areas in the brain required for doing the task appeared to activate more intensely than before, and also, areas lit up that were not necessarily involved in completing the task,” said the study’s first author Matt Wittbrodt. “We think the latter may be in response to the physiological state: the body signalling, ‘I’m dehydrated’.”

The task the subjects completed was mindless and repetitive. For 20 straight minutes, they were expected to punch a button every time a yellow square appeared on a monitor. Sometimes, the square appeared in a regular pattern, and sometimes it appeared randomly. The task was dull for a reason.

“It helped us to avoid the cognitive complexity behind elaborate tasks and strip cognition down to simple motor output,” Wittbrodt said. “It was designed to hit essential neural processing one would use to make straightforward, repetitive movements.” The study has been published in Physiological Reports.

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Simple Leg Exercises Can Reduce Negative Effects On Heart And Blood Vessels

Simple Leg Exercises Can Reduce Negative Effects On Heart And Blood Vessels

Did you know how beneficial are simple leg exercises while lying down? A sedentary lifestyle can cause an impairment of transportation of blood in the body which in turn may increase the risk of diseases in the heart and blood vessels. Performing simple leg exercises can make a huge change and prevent such problems, a new study reveals. Earlier work has demonstrated that prolonged sitting for up to 6 hours results in a decline in both blood flow to the limbs and in our larger arteries’ ability to widen to accommodate increased blood flow.

This is the first study to show that sitting for just 10 minutes is sufficient to reduce blood flow to the legs and impairs the function of small blood vessels supplying muscles in the leg.

This paper also highlights a reduction in the function of small blood vessels when lying down. However, this study suggests that we might be able to reverse this impairment to some extent by performing some simple leg exercises when lying down in bed or on the sofa.

The effects of sitting on blood circulation have been attributed to blood passing more slowly through arteries while sitting. The researchers aimed to find out whether these reductions were caused by sustained sitting, or whether 10 minutes would be sufficient to have a negative effect.

The researchers used a Doppler ultrasound technique alongside the knee to measure blood flow and examined the extent to which blood vessels widened in 18 healthy, young males. These measurements were made prior to and following a 10 -minute period of sitting or during a period of rest while lying down, with or without leg exercises, which were performed by extending the foot back and forth every two seconds for a third of the time spent lying down.

Results showed that a 10 minute period of sitting reduced participants’ ability to rapidly increase blood flow to the lower legs via small blood vessels, but it did not affect the widening of larger arteries in response to increased blood flow. The results also suggest leg exercises can help maintain rapid increases in the blood supply to the limbs.

The study demonstrates changes in blood vessel function measured at the level of the knee. However, the researchers only tested healthy young males and their findings cannot be extended to females. It remains unknown as to how these responses may vary with age, or with people who have heart problems.

Further study may investigate the impact of sitting and inactivity on blood vessels in other places in the body. Studies designed to investigate the impact of repeated bouts of short-term sitting on blood vessel function are needed.

“These findings further our understanding of the negative impact of inactivity on blood vessel function and demonstrate the positive effects of simple leg exercises whilst lying down providing further insight into how inactivity affects vascular health of the lower legs”, says study author Dr Paul Fadel.

The findings appeared in the journal Experimental Physiology.

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