islamabad - According to recent research, intermediate high-density lipoprotein cholesterol levels may help people have a longer life.

Cholesterol is a waxy, fat-like substance that the body needs to help build cells; it is carried through the bloodstream and attaches to proteins called lipoproteins. If blood vessels are damaged, cholesterol can be deposited, eventually causing narrowings. People with kidney disease are more likely to have problems with narrowings in their blood vessels than healthy people.

High-density lipoprotein (HDL) is known as the “good” cholesterol due to the way it assists with removing excess cholesterol from the bloodstream and taking it to the liver, where it is broken down and removed from the body. Higher levels of HDL cholesterol are linked to a lower risk of heart disease, heart attacks, and stroke.

Benjamin Bowe, MPH of Washington University School of Medicine, and Ziyad Al-Aly, MD FASN of Veterans Affairs Saint Louis Health Care System, and colleagues retrospectively studied 1,764,986 American male veterans.

However, findings from the study indicate that both low HDL cholesterol levels less than 25 mg/dL and high HDL cholesterol levels above 50 mg/dL were linked to an increased risk of premature death during follow-up. While intermediate levels between 25-50 mg/dL reduced the risk of early death, thus forming a U-shaped relationship between HDL cholesterol and mortality risk.  In the presence of kidney disease, the beneficial properties of intermediate HDL cholesterol levels were not as strong, but they remained significant.

“The finding that high HDL cholesterol was also associated with higher risk of death was not expected and has not been reported previously in large epidemiologic studies,” says Dr Al-Aly.

“Prior epidemiologic studies significantly advanced our understanding of the relationship between cholesterol parameters and clinical outcomes; however, these studies are limited in that the number of patients in these cohorts is relatively small compared with the current Big Data approach,” he adds.

He notes that a Big Data approach to the investigation allows a more refined examination of the relationship between HDL cholesterol and risk of death across the full spectrum of HDL cholesterol levels.

Exercise does not harm memory: Study

In 2014, a study claimed that new neurons created through physical activity erase old memories. Now, new research by scientists from Texas A&M College of Medicine finds this is not the case. For the new research, Shetty and team replicated the earlier study, but they used rats instead of mice. This is because the neuronal function of rats more closely resembles that of humans.

“This is pretty clear evidence that exercise greatly increases neurogenesis in the hippocampus, which has functional implications,” says first author Maheedhar Kodali, Ph.D., of the Institute for Regenerative Medicine at Texas A&M. “Neurogenesis is important for maintaining normal mood function, as well as for learning and creating new memories.”

The researchers then placed both groups of rats back in the water maze, in order to test whether they could remember how to navigate it.  The team found that the memory recall of the exercising rats was comparable with that of sedentary rats, suggesting that exercise has no detrimental effect on memory. This effect was the same for moderate and brisk runners.

The authors say their findings contradict those of the 2014 study, and they should come as welcome news for individuals who believed their morning run might have negative outcomes for memory.

Ph.D Ashok K. Shetty said that”Exercise is not at all harmful. It doesn’t cause any memory problems, and there are many studies proving its benefits for making new memories and maintaining good mood.

Now, our study showed that exercise does not interfere with memory recall ability. Keep exercising, and don’t worry about losing your old memories.”