Insufficient control of exercise intensity by heart rate monitoring in cardiac patients.

Objectives: To test the reliability of heart rate (HR) recommendations for cardiac rehabilitation training obtained from different treadmill tests.

Background: For training in cardiac rehabilitation, HR recommendations are derived from cardio-pulmonary tests. Exercise intensity is often controlled through self-monitoring HR by the cardiac patients.

Design: Non-randomized clinical trial.

Methods: 25 patients of a cardiac sports group (six women, 19 men, age 68.3 ± 5 years, height 171 ± 10 cm, weight 82 ± 12.8 kg) performed a stepwise increasing treadmill test according to a modified Stanford protocol (S) and a ramp treadmill test according to the Balke-Ware protocol (B) until volitional exhaustion. In 16 patients, HR was assessed with a HR monitor and compared with HR obtained by self-monitoring through pulse palpation during three training sessions.

Results: Similar peak cardiopulmonary responses were obtained with the two exercise protocols of significantly (p < 0.001) different duration (S 22:05 ± 7:11 min, B 13:31 ± 4:20 min). During the training sessions, HR exceeded the upper HR limit set at 85% HR(peak) in 15 patients and in nine patients, higher HR(peak) than in the exercise tests was observed. Five participants did not accurately measure their HR by pulse palpation.

Conclusions: All but one patient of the cardiac sports group did not adhere to the HR recommendations derived from incremental treadmill testing, most likely because volitional exhaustion occurred in both treadmill tests before maximal cardiopulmonary responses were reached. In about 30% of the patients, training intensity could not be controlled by self-monitoring because of inaccurate pulse palpation.