Tag: respiration

Categories : Exercise Immune SystemTags :

Firefighter Study Reveals how Extreme Exercise can Suppress the Immune System

On By ModernMedia
Source: CC0

A study of firefighters on a punishing training course has revealed clues as to why extreme exercise temporarily weakens the immune system – a phenomenon seen in elite athletes. The findings, published in Military Medical Research, may lead to better ways to support the health of people who undergo extreme exertion, such as firefighters tackling wildfires.

Thirteen firefighters volunteered for the study, average age 25 and male. They went through a rigorous training exercise, carrying 9 to 20kg of gear over hilly terrain during a 45-minute training exercise in the California sun. Gloves, helmets, flashlights, goggles, and more weighted them down as they sprinted through the countryside wearing fire-resistant clothing to show they were ready to serve as wildland firefighters.

After the training, they immediately gave samples of their blood, saliva, and urine for analysis. Two were excluded, one being unable to finish the course and the other arriving to late to provide a sample. The 11 participants who completed the course lost an average of 2.2% of their initial weight.

Then, the scientists from the Department of Energy’s Pacific Northwest National Laboratory (PNNL) analysed more than 4700 molecules, consisting of proteins, lipids, and metabolites, from each of the firefighters, looking to understand what happens when the body undergoes intense physical exercise. Measuring and interpreting the data from thousands of such measurements is a specialty of PNNL scientists who explore issues related to climate science and human health by analysing millions of sensitive measurements using mass spectrometry each year.

The researchers’ aim was to increase safety for first responders and others.

“Heat stress can be life threatening,” said Kristin Burnum-Johnson, a corresponding author of the study. “We wanted to take an in-depth look at what’s happening in the body and see if we’re able to detect danger from exhaustion in its earliest stages. Perhaps we can reduce the risk of strenuous exercise for first responders, athletes, and members of the military.”

As expected, the team detected hundreds of molecular changes in the firefighters. The differences before and after exercise underscored the body’s efforts at tissue damage and repair, maintenance of fluid balance, efforts to keep up with increased energy and oxygen demand, and the body’s attempts to repair and regenerate its proteins and other important substances.

But in the saliva, the team found some unexpected results. There was a change in the microbial mix of the mouth – the oral microbiome – showing that the body was increasingly on the lookout for bacterial invaders. Scientists also saw a decrease in signaling molecules important for inflammation and for fighting off viral infections.

A decrease in inflammation makes sense for people exercising vigorously; less inflammation allows people to breathe in air more quickly, meeting the body’s eager demand for more oxygen. Having fewer inflammatory signals in the respiratory system helps the body improve respiration and blood flow.

Less inflammation, more inhalation

But less inflammation leaves the body more vulnerable to viral respiratory infection, which other studies observed in elite athletes and others who exercise vigorously. Some studies have shown that a person is up to twice as likely to come down with a viral respiratory infection in the days after an especially energetic workout.

“People who are very fit might be more prone to viral respiratory infection immediately after vigorous exercise. Having less inflammatory activity to fight off an infection could be one cause,” said Ernesto Nakayasu, a corresponding author of the paper. He notes that the work provides a molecular basis for what clinicians have noticed in their patients who do strenuous workouts.

The team hopes that the findings will help explain why come people are more vulnerable to respiratory infection after a workout.

Source: DOE/Pacific Northwest National Laboratory

Categories : LungTags :

Vaping Raises Oxidative Stress Levels Even in Nonsmokers

On By ModernMedia
Photo by Toan Nguyen on Unsplash
Photo by Toan Nguyen on Unsplash

In addition to the well-documented risks of smoking and vaping, a new UCLA study has revealed that a short vaping session can affect the cells of even healthy younger nonsmokers.

According to their study, published in JAMA Pediatrics, a single 30-minute vaping session can significantly increase cellular oxidative stress, which occurs when the body has an imbalance between free radicals, and the antioxidants which neutralise them.

“Over time, this imbalance can play a significant role in causing certain illnesses, including cardiovascular, pulmonary and neurological diseases, as well as cancer,” said the study’s senior author, Dr Holly Middlekauff, a professor of cardiology and physiology at the David Geffen School of Medicine at UCLA.

E-cigarettes, devices that deliver nicotine with flavouring and other chemicals in a vapour rather than smoke, are popularly seen as a safer cigarette alternative, but research by Prof Middlekauff and others has demonstrated that vaping is associated with a number of adverse changes in the body that can presage future health problems.

For the present study, 32 male and female study participants, aged 21 to 33, were split into three groups: 11 nonsmokers, nine regular tobacco cigarette smokers and 12 regular e-cigarette smokers. The researchers collected immune cells from each individual before and after a 30-minute vaping session to measure and compare changes in oxidative stress among the groups.

The researchers repeated this with a control session where participants spent 30 minutes “sham-vaping,” or puffing on an empty straw.

In nonsmokers, oxidative stress levels were found to be two to four times higher after the vaping session than before. Among the regular cigarette and e-cigarette smokers, the same 30-minute exposure did not lead to an increase in oxidative stress, the researchers noted, most likely because their baseline levels of oxidative stress were already increased.
“We were surprised by the gravity of the effect that one vaping session can have on healthy young people,” Prof Middlekauff said. “This brief vaping session was not dissimilar to what they may experience at a party, yet the effects were dramatic.”

The researchers noted that these results are especially troubling due to the increasing popularity of vaping, particularly among the youth. In a 2020 study, nearly a third of high school students reported e-cigarette use during the previous month.

There is still more to be understood about what exactly causes the changes in oxidative stress levels, whether it is caused by the nicotine or non-nicotine elements in e-cigarettes, which will be the subject of future research.

“While there’s a perception that e-cigarettes are safer than tobacco cigarettes, these findings show clearly and definitively that there is no safe level of vaping,” Prof Middlekauff said. “The results are clear, unambiguous and concerning.”

Source: UCLA

Categories : COVID PaediatricsTags :

Child Mask Study Which Reported High CO2 Levels Retracted

On By ModernMedia
Photo by Kelly Sikkema on Unsplash

A study which generated controversy by suggesting that masks may harm children through exposure to high carbon dioxide levels was retracted on Friday.

The research letter released in JAMA Pediatrics on June 30 had reported finding in a lab environment unacceptably high levels of CO2 by German standards in air inside masks worn by children.

The journal editors cited “numerous scientific issues” in the retraction notice, which also included questions over the applicability of the CO2 measurement device and the validity of the study’s conclusions.

“In their invited responses to these and other concerns, the authors did not provide sufficiently convincing evidence to resolve these issues, as determined by editorial evaluation and additional scientific review,” the notice read. “Given fundamental concerns about the study methodology, uncertainty regarding the validity of the findings and conclusions, and the potential public health implications, the editors have retracted this Research Letter.”

The study drew prompt criticism following its publication. Joseph Allen, MPH, DSc, who studies the impact of carbon dioxide on human health at Harvard School of Public Health in Boston, described the study as “terribly flawed”, predicting its retraction on Twitter. He pointed out that the study made no account of the flood of air taken in when children inhale, his key complaint.

The US Centers for Disease Control do not list any known risk wearing facing masks poses to children, and in fact, recently recommended that unvaccinated children wear masks when school reopen later this year. A previous study with adult volunteers had shown short-term but acceptable rises in CO2 when wearing masks,

While many areas of the US have dropped mask mandates, Los Angeles is reinstating its indoor mask mandate regardless of vaccination status as COVID cases and hospitalisations rise, presumably due to the spread of the Delta variant.

Source: MedPage Today