MENTAL CHALLENGE ELICITS ADDITIONAL INCREASES IN HEART-RATE DURING LOW AND MODERATE INTENSITY CYCLING

The combined effects of exercise and mental challenge on heart rate (H R) and T-wave amplitude (TWA) were studied. Twenty male students cycle d at low (40% of their relative maximal HR reserve (MHRR), for 15 min) and medium (60% MHRR, for 10 min) intensity exercise workloads. Subje cts performed a series of mental arithmetic problems for one minute ea ch time: two min before cycling, 10 min into low intensity cycling, 10 min into medium intensity cycling, and two and 20 min, respectively, after cycling. During both exercise workloads, the mental arithmetic e licited significant additional increases in HR. Although TWA decreased in response to mental arithmetic at rest, no changes in TWA were obse rved in response to mental task during exercise. However, TWA increase d significantly following the mental challenge. These results suggest that even a mild mental challenge is capable of inducing further chang es in the autonomic response during low and moderate exercise.