Every breath you take: professor looks at lungs? response to exercise

Watching super-fit Olympic athletes performing in Beijing - some winning and some flailing - one can't help but wonder what makes the difference between the athletes who storm the finish line and those who come up short, seemingly running out of steam when they need it most.

It could be something as simple how their lungs process air, according to Dr. Alastair Hodges.

Hodges, a human exercise physiologist, and a recent hire to the faculty from Dalhousie University in Nova Scotia, performs research looking at gas exchange in the lungs - the process of breathing in oxygen and breathing out carbon dioxide - to understand how lungs respond to exercise and how they interact with other systems in the body during exercise.

"In the past, the traditional notion was that lungs perform quite well when humans exercise, assuming that the person is healthy and has no lung disease or asthma," says Hodges. "Lungs don't limit exercise and they don't really adapt that much to chronic exercise training as skeletal muscle or the heart do."

But that doesn't always hold true. "In some high-performance athletes there are problems with gas exchange - and scientists have had a hard time explaining exactly why it's happening," he says, adding that it typically occurs in highly-trained aerobic athletes such as runners, cyclists, tri-athletes and swimmers who are exercising at a high intensity.

"It's not a health threat," emphasizes Hodges, "and the athlete won't notice the performance decrement or even know it is happening because you can't feel it but it is noticeable and it can be measured in the lab."

And it can impact performance.

"It has been shown than when people don't have perfect gas exchange during exercise, they can lose about one percent of their VO2 max (a measure of the maximal rate at which oxygen can be taken in, transported and used by the body to perform muscular work) for every percentage point drop of oxygen in the blood," explains Hodges. In real terms that could mean for a world-class distance runner (e.g. 10,000m race), a few percentage points' decrement in VO2 max could be the difference between a gold medal and not qualifying for the Olympics.

Hodges will continue his work in the Integrative Human Exercise Physiology Lab at the U of A, delving further into the reasons why this happens. He will also be taking his research outdoors, looking at how altitude impacts gas exchange in the lungs. An avid outdoorsman with a recreational interest in mountains and hiking, Hodges says, "When you take people up to altitude, all bets are off in terms of gas exchange being the same as it is at sea level. The lungs have to perform differently than they do at sea level."

In addition, Hodges, who spent 16 seasons in the forestry industry as a tree-planter, crew leader and supervisor in his native British Columbia while putting himself through school, is also interested in occupational physiology and in looking at ways to improve the work environment for tree planters who typically work a physically gruelling 12-hour day, six days a week. "It's like an athletic event in some ways," says Hodges, who went out to prove this one summer, taking body composition measures of workers at the beginning and end of a season. "I found that people lost about three percent of body fat during a 10 week period, despite taking in about 5000 calories a day!"

Chronic injuries dog tree planters, notes Hodges. He's taken his share of knocks including having the ATV he was driving flip over on him, hurting his spine, and fracturing a rib in a separate incident. "Every tree planter I know has had tendonitis of some sort, whether wrist, knee or elbow, or some acute injury from a fall." He plans to apply for funding from Worker's Compensation in Alberta or WorkSafeBC to pursue this research interest. And he says, "I really like the idea of doing research and collecting data outside. If I can do that and publish research and make it a better work environment for others, that'll be rewarding."

This September, when students head back to the classroom, Hodges will be doing the other thing he loves: teaching. "I really like teaching," he says, "and at different levels; it's rewarding to see students become interested in something and succeed. But the main thing I want to get across in the classroom is for them to think objectively and critically."

Hodges is looking forward to taking on graduate students as well. "I think that much later, when I look back on my career, I think it'll be the mentoring of graduate students, having them be successful that will be the most rewarding part."