Arm ergometer provides alternative to conventional stress testing
The arm ergometer (also referred to as an arm cycle or arm crank) is a valuable alternative to the treadmill or leg cycle ergometer for exercise testing. In the arm ergometer stress test, the patient can sit or stand while cranking the arm ergometer. The test protocol is graded, just as a treadmill protocol, with increases in workload every two minutes until exhaustion. Either of two protocols may be used — one more vigorous and the other less so — depending on the age, sex and activity level of the patient.
Peak oxygen consumption on the arm ergometer is approximately 65 percent of treadmill peak oxygen consumption and 70 percent of leg cycle peak oxygen consumption, on account of the small exercising muscle mass. However, the peak heart rate reaches 90 to 95 percent of predicted with peak systolic blood pressure reaching 80 to 85 percent of what is typically achieved on the treadmill. Thus, the double product is generally high enough to bring out ischemic changes.
One obvious and well-studied application for arm ergometer stress testing is for patients with paraplegia or other severe lower extremity disability. The advantages of arm ergometry versus pharmacological stress testing for these patients are that heart rate and blood pressure responses can be evaluated and that exercise capacity and symptoms can be quantified.
Another use of arm ergometry is for testing patients who complain of symptoms only or primarily during arm work, a not uncommon presentation in clinical practice. Arm working capacity, as measured during arm ergometry, has been shown to correlate more strongly than functional aerobic capacity or peak VO2 from treadmill testing with performance on tasks such as shoveling, repetitive lifting and carrying loads.
Furthermore, arm exercise is characterized by reduced preload compared with leg exercise, as the lower limbs can act as a passive reservoir of blood, but afterload is elevated because of muscular contractions in the upper extremities. These hemodynamic aspects of arm work explain the generation of angina despite lower overall workload compared with walking.
Arm ergometry stress testing can be performed with or without simultaneous measurement of oxygen consumption.
For more information
For information about arm ergometry or any form of stress testing, contact Thomas G. Allison, Ph.D., director of the Integrated Stress Testing Center at 507-284-6320 or email firstname.lastname@example.org.