Significance of daily rhythm for the interpretation of functional diagnostic procedures.

For the first time, the reaction of the cardiovascular system during day and night in young people was examined. We were mostly interested in the influence of the nervous system and any autonomic mechanism. We examined 20 subjects at 4-hour intervals on the ergometer (active exercise) and on the tilt-table (passive exercise) to find out the rhythm in the circulatory regulation. The test person was kept in vertical position on the tilt-table for 10 minutes. On the ergometer he had to perform a work-load of 100 Watt for 10 minutes. We measured pulse rate and blood pressure; we introduced new terms for the evaluation. "Orthostatic Index" and "Performance Index" will be further explained. The results were: A minimum in the orthostatic stability around 1 p.m. and 1--5 am, and a performance maximum at 1 p.m. and 5 p.m. Further details will be reported.