Islamabad-Just 2 days of sleep loss may trigger changes in gut microbiota that are associated with poor metabolic health.

According to the researchers of the new study - including first author Christian Benedict of the Department of Neuroscience at Uppsala University in Sweden - some studies in mice and humans have suggested that gut bacteria have a circadian rhythm that might be disrupted by sleep loss.  “However, to date, there are no studies that have investigated the impact of insufficient sleep on the composition of the human gut microbiota,” they add

While the team found no evidence that sleep loss alters the diversity of gut bacteria, their analysis did identify changes in microbiota - such as an increase in the ratio of Firmicutes to Bacteriodetes - that previous studies have associated with obesity.  Additionally, the researchers found that following sleep restriction, subjects showed a 20 percent reduction in sensitivity to insulin - the hormone that regulates blood glucose levels. 

“This decreased insulin sensitivity was however unrelated to alterations in gut microbiota following sleep loss,” says Benedict. “This suggests that changes in microbiota may not, at least in the short-term, represent a central mechanism through which one or several nights of curtailed sleep reduce insulin sensitivity in humans.”

While these findings suggest sleep loss can trigger changes in gut bacteria, the researchers say further investigation is warranted to better understand whether these changes influence metabolic health. 

The authors add:

“Given our small sample size that only involved healthy young men, larger and more long-term studies are required to investigate to what extent these findings persist over longer time periods and whether these are observed in females, older or diseased patients and in other sleep restriction paradigms.  Nevertheless, our study is the first to provide evidence for sleep deprivation-induced changes in microbial families of bacterial gut species, which have previously been linked to metabolic pathologies.”

Meanwhile Lack of sleep has been linked to increased risk of numerous health problems, including high blood pressure, stroke, heart disease, obesity, and type 2 diabetes.

Stronger muscles can improve brain’s cognitive function

The results of recent research revealed that gradually increasing muscle strength through activities such as weightlifting improves cognitive function. The study was conducted in collaboration with the Centre for Healthy Brain Ageing (CHeBA) at the University of New South Wales and the University of Adelaide.

The findings are particularly significant given the high incidence of dementia and Alzheimer’s disease among the aging population. It has been suggested that exercise indirectly helps prevent the onset of Alzheimer’s disease and lowers the risk of cognitive impairment. Exercise helps with physiological processes such as glucoregulation and cardiovascular health. When these are sub-optimal, they increase the risk of cognitive impairment and Alzheimer’s disease.  Exercise also improves other cognitive processes, such as selective attention, planning, organizing, and multitasking.

Some studies have also suggested a connection between an increase in the size of certain brain areas and exercise training.

With age, the hippocampus is known to reduce in size, which leads to cognitive impairment. However, aerobic exercise has shown an increase in the size of the anterior hippocampus by 2 percent, which can improve spatial memory.

Earlier this year, a team of researchers that included Dr. Mavros released a similar test where they noticed cognitive improvement after weightlifting.

Using functional magnetic resonance (fMRI), they analyzed changes in the brain after 6 months of progressive resistance training and computerized cognitive training in older adults. They found that progressive resistance training such as weightlifting “significantly improved global cognition.”

Authors of this study pointed out that it remains unclear whether physical training in itself stops the degenerative effects of old age, or whether they boost some other mechanisms that support cognition.

Although muscle strength seems to be clearly connected with cognitive impairment, the mechanism behind it is still not entirely evident.

Men’s mental health influenced by blood pressure, heart

rate in adolescence

A study finds that differences in heart rate and blood pressure in late adolescence may be associated with an increased lifetime risk for psychiatric disorders, including obsessive-compulsive disorder, schizophrenia, and anxiety disorders.

Antti Latvala, PhD, of the University of Helsinki in Finland, and co-authors included several potential factors that may influence the outcome of the results, including physical, cognitive, and socioeconomic factors.

According to the study authors, IQ is associated with psychiatric morbidity, although its association with resting heart beat and blood pressure is unknown.

Similarly, compared with males in the lower heart rate category, men in the higher heart rate category had a 21 percent increased risk for schizophrenia and an 18 percent greater risk for anxiety. In contrast, teenage males with a lower resting heartbeat were linked to substance use disorders and violent convictions, particularly after adjusting for physical fitness.

The study authors reported similar associations for OCD, schizophrenia, anxiety, substance use disorders, and violence with higher and lower blood pressure readings.

“In this large-scale longitudinal cohort study, we found men with higher resting heart rate and higher blood pressure in late adolescence to be more likely to have received a diagnosis of OCD, schizophrenia, or anxiety disorder later in life,” say the authors.

The strongest associations were seen with OCD, with men in the higher resting heart rate category 70-80 percent more likely to be at risk than men in the lower category. Correspondingly, men in the highest blood pressure category had a 30-40 percent greater risk for OCD than men in the lowest blood pressure category.

Our findings are novel; there are no previous prospective studies linking these cardiovascular measures to subsequent OCD, schizophrenia, or anxiety disorders,” the researchers note. However, they say that their findings cannot establish cause and effect.

The researchers point out that the data included were for men; therefore, it is uncertain whether the same results would be seen in women.

“Compared with men, women have a higher heart rate but show relatively greater parasympathetic control of the heart,” note the authors. “While these differences are poorly understood, they imply that associations between resting heart rate and psychiatric disorders may be different in men and women.”