“Lewis and Clark Reloaded: The 3,041-Mile Bike Trail”
Mary Rose Grant
School for Professional Studies
Saint Louis University
Part I—The Adventure Begins … and Comes to a Screaming Halt
1. What body systems are primarily affected and what physiological changes would you expect Joe and Frank to experience during such rigorous exercise?
You may list, as students report out, the physiological changes to the respiratory, cardiovascular, neuromuscular, and urinary systems expected during strenuous exercise and as noted in the case of the cyclist, Joe. Students will respond with answers suggesting increases in heart rate, respiration, sweating and muscle fatigue, as well as muscle soreness as normal. However, in reality, in an effort to sustain maximum energy output over extended periods of time, endurance athletes train so that organ systems make the necessary physiological adaptations and are not subject to radical changes in function. Metabolic changes can occur with extensive endurance training in the muscles, hearts and lungs of the athlete, increasing efficiency of system utilization (Thompson, 2000).
In cycling, due to the posture of the athlete, increased arterial pressures in the lower limbs may cause both a pressure and volume overload on the heart (O’Toole and Douglas, 1995). Intensive training and long endurance events are accompanied by some muscle damage, due to decreases in myoglobin and build up of lactic acid in the tissue (Armstrong, 1986). The VO2 max (aerobic capacity) is important in the transfer of energy. This requires an integration of the respiratory, cardiovascular and neuromuscular systems. Mahler et al (1982) reported that the respiratory system is not a limiting factor in marathon runners, finding no difference between their respiratory function and that of their sedentary controls. Therefore only the cardiovascular and the neuromuscular systems adapt to endurance training.
2. List the symptoms Joe is manifesting on the 20th day of cycling.
Joe manifested the following symptoms:
a. loss of motor control
c. visual sensitivity
d. heart pounding
f. general fatigue in voice
g. aching and weak muscles and stiff joints
h. splitting headache
i. stomach ache
k. loss of consciousness
3. Could Joe’s symptoms be explained by your answers to Question #1 alone?
Some of Joe’s muscle soreness and fatigue may be explained by what is expected for any endurance athlete 20 days into his training and during the event. However, since it appears that the cyclists trained sufficiently prior to the event and had adequate nutrition and hydration during the event, the signs of disorientation, headache, stomach ache, and abnormal behavior must be attributed to some other cause.
Part II—A Change of Scenery
1. What, if any, of this new information might be relevant to this case?
New information presented:
a. Joe’s vital signs: Temperature—99.1 degrees
Heart rate—87 beats per minute
Weight on admission—171 lbs.
b. Joe is nauseous and vomiting
c. Joe and Frank drank plenty of fluids during the trip
d. Joe drank high energy drinks and espresso twice a day, Frank drank water e. Joe and Frank routinely rested and stretched muscles f. Joe and Frank experienced tightened hand and finger muscles g. Both brothers ate high protein and nutritious meals h. For added energy Frank ate peanuts and Joe ate chocolate.
Both brothers seem to be following nearly the same daily exercise, diet, and rest routines, but only one became ill. Joe’s blood pressure and pulse rate are elevated. His temperature is normal as is his admitting weight, down only 8 lbs. from his pre-cycling start weight of 179 lbs.
2. What can you determine from the clinical lab results of Joe’s blood work and urinalysis?
Joe’s blood work indicates that there was some above average fluid loss with the high red blood cell count and increased...