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.

[“source=hindustantimes”]

Cardiovascular diseases, here’s how exposure to toxic metals can affect your heart health

Cardiovascular Health,Toxic Metals,Lead

Exposure to environmental toxic metals such as arsenic, lead, copper, and mercury has become a major global health concern. The metals like arsenic, lead, copper and cadmium are linked to an increased risk of cardiovascular disease and coronary heart disease.

Arsenic and cadmium, for example, are known carcinogens, but there are increasing suggestions that exposure to toxic metals may be an independent risk factor for cardiovascular disease.

To investigate further, an international research team, led by Rajiv Chowdhury at the University of Cambridge, reviewed and analysed the results of epidemiological studies that had looked at the association of arsenic, lead, copper, cadmium, and mercury with coronary heart disease, stroke and composite cardiovascular disease.

They identified 37 separate studies published before December 2017 involving almost 350,000 participants. A total of 13,033 coronary heart disease, 4,205 stroke and 15,274 cardiovascular outcomes were reported across the studies.

The studies were designed differently and were of varying quality, but the researchers were able to allow for that in their analysis. Exposure to arsenic was found to be significantly associated with a 23% greater relative risk of coronary heart disease and a 30% greater relative risk of composite cardiovascular disease, but there was no evidence of an association with risk of stroke.

Exposure to cadmium and copper was also associated with increased relative risks of coronary heart disease and cardiovascular disease, while lead and cadmium were associated with an increased relative risk of stroke (63% and 72% respectively).

In contrast, mercury was not found to be associated with cardiovascular risk. The researchers point out that their review was solely based on observational data, which might be affected by unmeasured factors, making it difficult to draw firm conclusions about cause and effect.

Nevertheless, they say their findings “reinforce the (often under-recognised) importance of environmental toxic metals in enhancing global cardiovascular risk, beyond the roles of conventional behavioural risk factors, such as smoking, poor diet and inactivity.”

Furthermore, they say their study highlights the potential need for additional worldwide efforts and strategies “to reduce human exposures even in settings where there is a relatively lower average level of exposure (such as many Western countries).”

[“source=hindustantimes”]