How sleep apnea affects aerobic fitness

This study discusses how aerobic fitness can be affected by having sleep apnea.

People with sleep apnea may have lower levels of aerobic fitness, a new study suggests.

Sleep apnea causes the upper airway to become blocked by soft tissue in the back of the throat during sleep. This causes pauses in breathing and other symptoms, such as gasping and snoring.

The research included 15 adults with moderate to severe obstructive sleep apnea and a comparison group of 19 adults with mild or no apnea. They pedaled a stationary bike at increasingly harder resistance levels -- similar to climbing up a progressively steeper hill -- and kept going until exhaustion.

On average, people in the sleep apnea group scored 14 percent lower on a test that measures the maximum amount of oxygen a person can take in during intense exercise. This measurement is called VO2 max.

People with sleep apnea are more likely to be overweight or obese, and thus less fit, the researchers noted. However, they found that people with sleep apnea had poorer aerobic fitness than those in the comparison group, even if they were the same body size.

Although this study found an association between lower oxygen intake during activity and sleep apnea, it wasn't designed to prove that sleep apnea was the definitive cause of this difference.

Results of the study were published in the Nov. 15 issue of the Journal of Clinical Sleep Medicine.

"Encouraging patients to exercise more is part of the story, but that is not the whole story," lead author Dr. Jeremy Beitler, assistant clinical professor in pulmonary and critical care medicine at the University of California, San Diego School of Medicine, said in a university news release.

"We believe the sleep apnea itself causes structural changes in muscle that contributes to their difficulty exercising," he added.

The researchers said measuring VO2 max may help identify sleep apnea patients at increased risk for heart attack and stroke, which could encourage earlier treatment of sleep apnea, which is underdiagnosed and often untreated.

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Any physical activity benefits your brain

This study observes how any physical activity has positive benefits for adult brains. -JR

Everyone knows that exercise makes you feel more mentally alert at any age. But do you need to follow a specific training program to improve your cognitive function? Science has shown that the important thing is to just get moving. It's that simple. In fact, this was the finding of a study conducted at the Institut universitaire de gériatrie de Montréal (IUGM), an institution affiliated with Université de Montréal, by Dr. Nicolas Berryman, PhD, Exercise Physiologist, under the supervision of Dr. Louis Bherer, PhD, and Dr. Laurent Bosquet, PhD, that was published in the journal AGE (American Aging Association) in October.

The study compared the effects of different training methods on the cognitive functions of people aged 62 to 84 years. Two groups were assigned a high-intensity aerobic and strength-training program, whereas the third group performed tasks that targeted gross motor activities (coordination, balance, ball games, locomotive tasks, and flexibility). While the aerobics and strength-training were the only exercises that led to physical fitness improvements after 10 weeks (in terms of body composition, VO2 max, and maximum strength), all three groups showed equivalent improvement in cognitive performance.

The subjects in the third group performed activities that can easily be done at home, which is excellent news for sedentary people who can't see themselves suddenly going to a gym to work out. To improve your cognitive health, you can simply start by doing any activity you like.

"Our study targeted executive functions, or the functions that allow us to continue reacting effectively to a changing environment. We use these functions to plan, organize, develop strategies, pay attention to and remember details, and manage time and space," explained Dr. Louis Bherer, PhD.

"For a long time, it was believed that only aerobic exercise could improve executive functions. More recently, science has shown that strength-training also leads to positive results. Our new findings suggest that structured activities that aim to improve gross motor skills can also improve executive functions, which decline as we age. I would like seniors to remember that they have the power to improve their physical and cognitive health at any age and that they have many avenues to reach this goal," concluded Dr. Nicolas Berryman, PhD.

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PTSD and poor sleep

A study claims that poor sleep in people with PTSD could lead to a decrease in physical activity and an increase in obesity.

Poor sleep quality may lower physical activity in people with post-traumatic stress disorder, according to a recent study.

Researchers found that PTSD was independently associated with worse sleep quality at baseline, and participants with current PTSD at baseline had lower physical activity one year later.

Further analysis found that sleep quality completely mediated the relationship between baseline PTSD status and physical activity at the one-year follow-up, suggesting that the association of reduced sleep quality with reduced physical activity could comprise a behavioral link to negative health outcomes such as obesity.

"We found that sleep quality was more strongly associated with physical activity one year later than was having a diagnosis of PTSD," Lisa Talbot, lead author of the study and postdoctoral fellow at the San Francisco VA Medical Center and the University of California- San Francisco, said in a statement. "The longitudinal aspect of this study suggests that sleep may influence physical activity."

For the study, researchers collected and analyzed data from  the Mind Your Heart Study, a prospective cohort study of 736 outpatients recruited from two Department of Veterans Affairs (VA) medical centers. PTSD was assessed with the Clinician-Administered PTSD Scale (CAPS).  At baseline participants rated their sleep quality overall during the last month, and at baseline and again one year later they reported how physically active they have been during the last month. Of the 736 military veteran participants, 258 had current or subsyndromal PTSD.

Researchers said the results suggest that behavioral interventions to increase physical activity should include an assessment for sleep disturbance.

"The findings also tentatively raise the possibility that sleep problems could affect individuals' willingness or ability to implement physical activity behavioral interventions," Talbout said. "Sleep improvements might encourage exercise participation."

The findings were recently published in the  Journal of Clinical Sleep Medicine, which is published by the American Academy of Sleep Medicine.

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Study: Exercise improves brain activity and memory in adults

A study claims that aerobic exercise has many benefits for adults including improved brain activity and memory in addition to physical fitness.

A new study conducted by researchers at the Center for BrainHealth at The University of Texas at Dallas published online in the open-access journal Frontiers in Aging Neuroscience found that engaging in a physical exercise regimen helps healthy aging adults improve their memory, brain health and physical fitness. This finding is significant considering that among adults 50 and older, "staying mentally sharp" outranks social security and physical health as the top priority and concern in the United States.

"Science has shown that aging decreases mental efficiency and memory decline is the number one cognitive complaint of older adults," said Sandra Bond Chapman, Ph.D., founder and chief director of the Center for BrainHealth, Dee Wyly Distinguished University Chair and lead author of the paper. "This research shows the tremendous benefit of aerobic exercise on a person's memory and demonstrates that aerobic exercise can reduce both the biological and cognitive consequences of aging."

For the study, sedentary adults ages 57-75 were randomized into a physical training or a wait-list control group. The physical training group participated in supervised aerobic exercise on a stationary bike or treadmill for one hour, three times a week for 12 weeks. Participants' cognition, resting cerebral blood flow, and cardiovascular fitness were assessed at three time points: before beginning the physical exercise regimen, mid-way through at 6 weeks, and post-training at 12 weeks.

"By measuring brain blood flow non-invasively using arterial spin labeling (ASL) MRI, we can now begin to detect brain changes much earlier than before," said Sina Aslan, Ph.D., founder and president of Advance MRI and collaborator on the study. "One key region where we saw increase in brain blood flow was the anterior cingulate, indicating higher neuronal activity and metabolic rate. The anterior cingulate has been linked to superior cognition in late life."

Exercisers who improved their memory performance also showed greater increase in brain blood flow to the hippocampus, the key brain region affected by Alzheimer's disease. Chapman pointed out that, using noninvasive brain imaging techniques, brain changes were identified earlier than memory improvements, implicating brain blood flow as a promising and sensitive metric of brain health gains across treatment regimens.

"Physical exercise may be one of the most beneficial and cost-effective therapies widely available to everyone to elevate memory performance," Chapman said. "These findings should motivate adults of all ages to start exercising aerobically."

Chapman cautioned that while physical exercise is associated with a selective or regional brain blood flow, it did not produce a change in global brain blood flow.

"In another recent study, we have shown that complex mental training increases whole brain blood flow as well as regional brain blood flow across key brain networks," Chapman said. "The combination of physical and mental exercise may be the best health measures to improve overall cognitive brain health. We have just begun to test the upper boundaries of how we can enhance our brain's performance into late life. To think we can alter and improve the basic structure of the mature brain through aerobic exercise and complex thinking should inspire us to challenge our thinking and get moving at any age."

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