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BOSTON COLLEGE BIOLOGY

 

 

Immune response to physical exhaustion

during the Race Across America (RAAM)

a case report

 

Larrabee (1), who reported a large increase in blood neutrophils among four athletes who ran the 1901 Boston Marathon, approached the relationship between heavy exertion, immunity and infection early in the century. About 30 years later, Baetjer (2) in a review of exercise and infection, indicated that, although the prevailing view is that muscular fatigue lowers resistance and is a predisposing factor to infectious diseases, little experimental work had been done to test this relationship scientifically.

 

Today, we know much more about the acute immune response to prolonged and intensive endurance exercise (3). Heavy exertion has been associated with the following changes in immunity:

1. Neutrophilia and lymphopenia.

2. Increase in blood granulocytes and monocyte phagocytosis.

3. Decrease in NK cell cytotoxicity activity.

4. Decrease in mitogen-induced lymphocyte proliferation.

5. Increase in pro-and anti-inflammatory cytokines (IL-6 and IL-1ra).

 

However, the emphasis in exercise immunology has been largely based on two situations of exercise stress: the situation of acute time-limited stress, in which individuals are given a single bout of exercise (90’ to 3h) and immune parameters are measured before and after; and the situation of chronic exercise, in which occurrence of clinical disease is tracked in elite athletes and the immunological profile is then correlated with disease episodes. Far less is known about either chronic intermittent exercise stress or chronic exercise stress with superimposed acute episodes (4).

 

Race Across America (RAAM) is a non-stop 3,000 miles bike race that usually pushes the solo riders way beyond their physical and mental limits. To complete the race, one has to ride 22 hours a day for 12 days. Sleep deprivation plays a huge role and there is no resting period on RAAM.

 

The aim of this study is to measure lymphocytes, monocytes and dendritic cells subsets changes during physical and emotional exhaustion. No scientific studies have ever been done in a context of an extreme race where not only resting is simply not possible for 12 days, but also the physical effort is enormous. Changes in the immune system and the blood parameters will probably be dramatic, and more profound than what has been published before. Naturally, a baseline (before the race) and the recovery period will be measured as well, to see how fast or slow the immune system and the blood parameters go back to normal.

 

Larrabee, R. C. Leucotysosis after violent exercise. J. Med. Res. 7: 76-82, 1902

 

Baetjer, A. M. The effect of muscular fatigue upon resistance. Physiol. Rev. 12: 453-468, 1932

 

Nieman, D. C. Immune response to heavy exertion. J. Applied. Physiol. 82: 1385-1394, 1997.

 

Hoffman-Goetz, L and Pedersen, B. K. Exercise and the immune system: a model of the stress response? Immunol. Today. 15: 382-387, 1994

 

 

 

 

BOSTON COLLEGE PSYCHOLOGY

 

 

The Effects of Physical Exertion

on Memory: A Case Study

 

 

Introduction and Background

 

It is well known that stress can influence memory, but the direction of these effects often varies depending on the duration of the stressor and the phase of memory that is assessed.  It has been proposed that circulating stress hormones impair memory retrieval and the maintenance of information in working memory, while simultaneously boosting the ability for new information to be consolidated into memory (Roozendaal et al., 2008).  The present study will take advantage of a unique opportunity to examine the effects of extreme physical stress on memory by following an individual from the Biology department (Patrick Autissier) as he completes a bike race across the country (the Race Across America, or RAAM; www.raceacrossamerica.org).

 

 

Specific Aims/Study Objectives

 

- To gather memory assessments as a bike racer puts himself under extreme physical stress in order to complete a race across country.

- To analyze these data to reveal the effects of stress on different forms of human memory.

 

 

Materials, Methods, and Data Analysis

 

This race will take place over two weeks in June.  A student researcher (Maite Balda) will follow the bike racer during these entire two weeks, trailing in a van that will include an intercom system to communicate with the biker. Memory assessments be given at a baseline time period (prior to the commencement of the race), at multiple time points during the race, and at a time point after the race’s completion.

 

Analyses will examine how memory performance is affected by factors including: heart rate, blood pressure, amount of time since sleep, duration of sleep, amount of time since caloric intake, number of calories consumed, and level of exertion exerted prior to the memory assessment.

 

 

References

 

Roozendaal B, Barsegyan A, Lee S. (2008). Adrenal stress hormones, amygdala activation, and memory for emotionally arousing experiences.