Sunday December 8, 2019

Human Body May Not Cope With Evening Stress, Study Reveals

The team first measured the diurnal rhythm of salivary cortisol levels from the volunteers and then exposed one group to stress test in the morning, and another to the evening

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Your body may not cope with evening stress: Study. Pixabay

Human bodies which experience stress in the evening release less cortisol — the primary stress hormone in humans — compared to stressful events in the morning, and thus may pose vulnerabilities, according to a new research.

The study, led by medical physiologist Yujiro Yamanaka at Japan’s Hokkaido University, the body’s central system reacts less strongly to acute psychological stress in the evening than it does in the morning, suggesting possible vulnerability to stressful events in the evening.

“Our study suggests a possible vulnerability to stress in the evening. However, it is important to take into account each individual’s unique biological clock and the time of day when assessing the response to stressors and preventing them,” Yamanaka commented.

The study, published in the journal Neuropsychopharmacology Reports, explored a small group of young and healthy volunteers with normal work hours and sleep habits to find out if the “hypothalamic-pituitary-adrenal” (HPA) axis responds differently to acute psychological stress according to the time of day.

The HPA axis connects the central nervous and endocrine systems of the body. Cortisol is released for several hours when the HPA axis is activated by a stressful event.

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Representational image. Pixabay

This helps provide the body with energy in the face of a perceived need for fight or flight. Cortisol levels are also regulated by a master circadian clock in the brain and are normally high in the morning and low in the evening.

The team first measured the diurnal rhythm of salivary cortisol levels from the volunteers and then exposed one group to stress test in the morning, and another to the evening.

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The researchers found that salivary cortisol levels increased significantly in the volunteers that took the stress test in the morning while no such response was observed in those that took the test in the evening.

“Our body can respond to the morning stress event by activating the HPA axis and sympathetic nervous system, but it needs to respond to evening stress event by activating the sympathetic nervous system only,” Yamanaka said. (IANS)

Next Story

Deep Sleep Can Reduce Higher Anxiety Levels

A Study strongly suggests that insufficient sleep amplifies levels of anxiety and, conversely, that deep sleep helps reduce such stress

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Deep Sleep had restored the brain's prefrontal mechanism that regulates our emotions, lowering emotional and physiological reactivity and preventing the escalation of anxiety. Pixabay

Researchers have found that the type of Sleep most apt to calm and reset the anxious brain is deep sleep, also known as non-rapid eye movement (NREM) slow-wave sleep, a state in which neural oscillations become highly synchronised, and heart rates and blood pressure drops.

A sleepless night can trigger up to a 30 per cent rise in anxiety levels, researchers from the University of California said.

“We have identified a new function of deep sleep, one that decreases anxiety overnight by reorganising connections in the brain,” said study senior author Professor Matthew Walker.

“Deep sleep seems to be a natural anxiolytic (anxiety inhibitor), so long as we get it each and every night,” Walker added.

“Our study strongly suggests that insufficient sleep amplifies levels of anxiety and, conversely, that deep sleep helps reduce such stress,” said study lead author Eti Ben Simon.

In a series of experiments using functional MRI and polysomnography, among other measures, researchers scanned the brains of 18 young adults as they viewed emotionally stirring video clips after a full night of sleep, and again after a sleepless night.

Anxiety levels were measured following each session via a questionnaire known as the state-trait anxiety inventory.

After a night of no sleep, brain scans showed a shutdown of the medial prefrontal cortex, which normally helps keep our anxiety in check, while the brain’s deeper emotional centres were overactive.

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Researchers have found that the type of Sleep most apt to calm and reset the anxious brain is Deep sleep, also known as non-rapid eye movement (NREM) slow-wave sleep, a state in which neural oscillations become highly synchronised, and heart rates and blood pressure drops. Pixabay

After a full night of sleep, during which participants’ brain waves were measured via electrodes placed on their heads, the results showed their anxiety levels declined significantly, especially for those who experienced more slow-wave NREM sleep.

“Deep sleep had restored the brain’s prefrontal mechanism that regulates our emotions, lowering emotional and physiological reactivity and preventing the escalation of anxiety,” Simon said.

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Beyond gauging the sleep-anxiety connection in the 18 original study participants, the researchers replicated the results in a study of another 30 participants.

Across all the participants, the results again showed that those who got more nighttime deep sleep experienced the lowest levels of anxiety the next day.  (IANS)