UMMC fellow studies impact of distance running on immunity
By Patrice Sawyer Guilfoyle
Inspiration for Dr. Kristina Rehm's postdoctoral research developed from her love of running and the conversations she had with fellow running enthusiasts.
Training to run a marathon - 26.2 miles - requires discipline and puts demands on the body, both mentally and physically. Some runners report illnesses in the days to weeks following a marathon.
Because Rehm, a fellow in the Division of Clinical Immunology and Allergy, studies the effects of stress on the immune system and knows all too well that marathon training can be stressful, she wondered if there was a link between the psychological stress of marathon training and the weakened immune system in some runners after a marathon.
She thought it would be interesting to measure the stress and anxiety levels in people training for a marathon and to see if these had any effect on the immune system.
This curiosity planted the seed for a study, and she credits Dr. Gailen Marshall, director of clinical immunology and allergy, with helping her focus her idea. He said the pilot study, which includes about 25 marathon runners in the Jackson area, has the potential to reach beyond the world of running to include people in high-stress jobs, such as firefighters, military personnel, police officers or astronauts.
"The real value of this study is to not only show stress causes changes in the immune system, but it will also establish the next stage," Marshall said. "The hope is that the study will lead to interventions that could prevent illness in people involved in stressful situations."
Rehm has a background in exercise physiology and immunology, and Marshall has an extensive background in psychoneuroimmunology. The combination of skills made for a perfect research match.
The research team's mission is to examine the effects of psychological and physiological stress on various components of the immune system, and ultimately to identify the stress-susceptible individual.
"We first want to establish marathon training/preparation as a model for stress," Rehm said. "We then want to be able to show that this stress has an impact on the immune system, which may or may not translate into clinical disease, such as cold, flu, allergy flare-ups and cold sores."
Rehm said another study of 2,000 runners showed they were six times more likely to get sick in the week following a marathon compared to people that did not participate.
She said distance running has grown in popularity in the Jackson area. Participation in the Mississippi Blues Marathon increased by 9 percent this year compared to last year, and the half-marathon grew by 30 percent this year. The research team is studying runners who participated in that marathon and those who will participate in the New Orleans marathon in March.
The study team sees participants three times during the month before and the month after the race. At each visit, they are asked questions about their perceived stress levels, anxiety, worry and depression. The team also collects saliva to check stress hormone levels, and blood samples to measure specific T cell populations of the immune system.
The study visits are completed one month before the marathon, 24-48 hours before the marathon and one week after the marathon. One month after the marathon, they call participants to find out if any of them became sick.
"Other studies look at factors immediately after the race," Rehm said. "Our study is different in that we follow participants both before and after the race, and we are specifically looking at how the psychological component of marathon training can affect the immune system."
Marshall said so much of human disease has an inflammatory basis, from lung conditions to heart disease. He said the mind-body connection is important.
"Our psychological makeup affects our health and our health affects our psychological make-up. You can't separate the two," he said. "There's so much physical, psychological and emotional stress that goes on in our lives every day.
"If we learn, using this model, that taking a gram of vitamin C daily will help prevent illness, it can be applied to people who are working two jobs a day to make ends meet."
Marshall said they are looking for ways to partner with other studies, such as the Jackson Heart Study, to delve further into the research on stress and health. Also, Rehm will be seeking additional funding from sources such as the Department of Defense or NASA to further her research.
She added that the pilot study has the potential to have community value as well.
"This research could also have applicability to various jobs where the individual experiences high levels of both psychological and physical stress. So we aim to not only keep our runners healthy, but also all of Mississippi."