Neurocardiologic and fitness changes in marathon skaters during interruption of training after their last competitive contest of the winter season

The authors studied nine male Dutch top marathon skaters during a one-month interruption of their training schedules after their last contest in the winter. Before and after this period a maximal exercise test was done, and at days 0, 4, 7, 14 and 28 neurocardiologic measurement sessions-heart rate (HR) and noninvasive baroreflex sensitivity (BRS), recumbent and tilt-were done. Interruption of training resulted in a significant and relevant decrease in the maximal oxygen uptake (from 65.7/spl plusmn/5.8 to 61.6/spl plusmn/4.7 ml O/sub 2/.kg/sup -1/. min/sup -1/; P=0.03), most likely to be associated with decreased competitive possibilities. A modest increase in resting heart rate (from 54.6/spl plusmn/7.2 to 58.8/spl plusmn/7.5 bpm) became not significant. Heart rate during 60/spl deg/ tilt increased considerably (from 70.3/spl plusmn/6.1 to 80.1/spl plusmn/9.1 bpm; P=0.01), possibly due to a decrease in blood volume and an increase in cardiopulmonary baroreflex gain. Baroreflex sensitivity decreased in the recumbent (from 13.3/spl plusmn/5.4 to 9.8/spl plusmn/3.8 ms/mmHg, P=0.04), but not in the 60/spl deg/ tilt position (from 6.7/spl plusmn/2.0 to 6.0/spl plusmn/2.5 ms/mmHg). The meaning of these neurocardiologic changes for athletic performance is unclear. The authors' data show that detrimental changes in fitness, and neurocardiologic changes were measurable after a month of interruption of training, and will probably also be demonstrable in a larger group after 14 days.