Case Study III: Health Screening and Analysis and Interpretation of GXT Data
John is a 38-year-old archeologist whose job requires some walking and hiking when he is collecting data in the field. However, much of his time is spent analyzing artifacts in the laboratory and writing research reports in his office. He is thinking about joining the employee fitness program at work, and therefore contacted you to evaluate his health risk and aerobic fitness level. His last medical examination was 3 months ago. You gave him a GXT using a Bodyguard cycle ergometer and collected the following data:
Client: 38-year-old male
Resting BP: 131/92 mmHg
Resting HR: 71 bpm
Total cholesterol: 210 mg · dl-1
Height: 5 ft 10 in. (177.8 cm)
HDL-cholesterol: 30 mg · dl-1
Body weight: 180.8 lb (82 kg)
Smoking history: 1 pack per day
Activity interests: cycling
Physical activity: job-related walking/hiking
GXT Data
Stage Min Work rate (kgm • min-1) HR BP RPE
1 1 180 110
2 180 115
3 180 119 168/92 7
2 4 360 130
5 360 136
6 360 138 180/90 13
3 7 540 151
8 540 158
9 540 163 215/88 16
Questions
1. On the basis of demographic data, evaluate this client's CHD risk profile. Given his CHD risk classification, did a physician need to be present during the GXT?
2. Identify any normalities or abnormalities in the HR and BP responses during the GXT.
3. What were the pedaling frequency and kg resistance for the third stage of this GXT protocol?
4. Why was this GXT terminated at stage 3?
5. Calculate the energy cost of each workload (three stages) using the ACSM leg ergometry formula. Convert ml · kg-1 · min-1 to METs for each stage.
6. Plot the client's HR versus workload (in METs) on graph paper.
7. What is the client's VO2max (in METs) using (a) the graphing method and (b) the multistage equation method?
8. What is this client's CR fitness classification?
9. Based on this fitness classification, determine the client's target (minimum and maximum) MET zone. Plot the target MET zone on the graph paper. Determine the corresponding target (minimum and maximum) exercise HRs to use to monitor exercise intensity during aerobic cycling workouts.
10. Now use the Karvonen (%HRR) method to identify the target HR zone (minimum and maximum). How do these target HRs compare to those you obtained using the HR versus MET graphing method?
11. How long will he need to cycle at the minimum exercise intensity (in METs) in order to expend 100 kcal during the aerobic workout?
12. What lifestyle changes do you recommend for this client?