The study included 165 symptomatic patients referred for exercise testing because of known or suspected coronary artery disease. Symptoms included chest pain or shortness of breath during exertion. Participants walked or ran on a treadmill, gradually increasing the intensity, and continuing until exhaustion. Exercise capacity was measured as metabolic equivalents (METs).2 After resting for 15 to 20 minutes, patients were asked to climb four flights of stairs (60 stairs) at a fast pace without stopping, but also without running, and the time was recorded.
The researchers analyzed the relationship between METs achieved during exercise testing and the time it took to climb four flights of stairs. Patients who climbed the stairs in less than 40-45 seconds achieved more than 9-10 METs. Previous studies have shown that 10 METs during an exercise test is linked with a low mortality rate (1% or less per year, or 10% in 10 years). In contrast, patients who took 1.5 minutes or longer to climb the stairs achieved less than 8 METs, which translates to a mortality rate of 2-4% per year, or 30% in 10 years.
During the treadmill test, the researchers also generated images of the heart to assess its function during exercise — if the heart works normally during exercise this indicates a low likelihood of coronary artery disease. They then compared these findings to the results of the stair climb. Some 58% of patients who completed the stair climb in more than 1.5 minutes had abnormal heart function during the treadmill examination. In contrast, just 32% of those who climbed the stairs in less than one minute had abnormal heart function during the treadmill examination.
Dr. Peteiro noted that the correlation between the stairs time and exercise capacity (i.e. METs) would be similar in the general population. But the corresponding mortality rates and heart function by imaging would be more favorable than for patients with symptoms and suspected or confirmed coronary artery disease.
For the record, I am a big fan of stair-climbing. Check out my posts, starting with 5 Reasons why stair-climbing is good for you.