Sloan et al. (A-31) note that cardiac sympathetic activation and parasympathetic withdrawal result in heart rate increases during psychological stress. As indicators of cardiac adrenergic activity, plasma epinephrine (E) and norepinephrine (NE) generally increase in response to psychological challenge. Power spectral analysis of heart period variability also provides estimates of cardiac autonomic nervous system activity. The authors conducted a study to determine the relationship between neurohumoral and two different spectral estimates of cardiac sympathetic nervous system activity during a quiet resting baseline and in response to a psychologically challenging arithmetic task. Subjects were healthy, medication-free male and female volunteers with a mean age of 37.8 years. None had a history of cardiac, respiratory, or vascular disease. Among the data collected were the following measurements on E, NE, low-frequency (LF) and very-low-frequency (VLF)

power spectral indices, and low-frequency/high frequency ratios (LH/HF). Measurements are given for three periods: baseline (B), a mental arithmetic task (MA), and change from baseline to task

(DELTA).

Patient No. E NE LF/HF LF Period VLF 5 3.55535 6.28040 0.66706 7.71886 B 7.74600 5 0.05557 0.13960 0.48115 0.99826 DELTA 2.23823 5 3.61092 6.41999 0.18591 6.72059 MA 5.50777 6 3.55535 6.24611 2.48308 7.33729 B 6.64353 6 0.10821 0.05374 2.03738 0.77109 DELTA 1.27196 6 3.66356 6.19236 0.44569 6.56620 MA 5.37157 7 3.29584 4.91998 0.15473 7.86663 B 7.99450 7 0.59598 0.53106 0.14086 0.81345 DELTA 2.86401 7 3.89182 5.45104 0.01387 7.05319 MA 5.13049 8 4.00733 5.97635 1.58951 8.18005 B 5.97126 8 0.29673 0.11947 0.11771 1.16584 DELTA 0.39078 8 4.30407 6.09582 1.47180 7.01421 MA 5.58048 12 3.87120 5.35659 0.47942 6.56488 B 5.94960 12 * * 0.19379 0.03415 DELTA 0.50134 12 * * 0.67321 6.59903 MA 6.45094 13 3.97029 5.85507 0.13687 6.27444 B 5.58500 13 0.20909 0.10851 1.05965 0.49619 DELTA 1.68911 13 3.76120 5.96358 1.19652 5.77825 MA 3.89589 Patient No. E NE LF/HF LF Period VLF 14 3.63759 5.62040 0.88389 6.08877 B 6.12490 14 0.31366 0.07333 1.06100 1.37098 DELTA 1.07633 14 3.95124 5.69373 1.94489 7.45975 MA 5.04857 18 4.44265 5.88053 0.99200 7.52268 B 7.19376 18 0.35314 0.62824 0.10297 0.57142 DELTA 2.06150 18 4.79579 6.50877 0.88903 6.95126 MA 5.13226 19 * 5.03044 0.62446 6.90677 B 7.39854 19 * 0.69966 0.09578 0.94413 DELTA 0.88309 19 2.94444 5.73010 0.72024 7.85090 MA 6.51545 20 3.91202 5.86363 1.11825 8.26341 B 6.89497 20 0.02020 0.21401 0.60117 1.13100 DELTA 1.12073 20 3.89182 6.07764 0.51708 7.13241 MA 5.77424 21 3.55535 6.21860 0.78632 8.74397 B 8.26111 21 0.31585 0.52487 1.92114 2.38726 DELTA 2.08151 21 3.87120 5.69373 1.13483 6.35671 MA 6.17960 22 4.18965 5.76832 0.02785 8.66907 B 7.51529 22 0.16705 0.05459 0.93349 0.89157 DELTA 1.00414 22 4.35671 5.71373 0.90563 7.77751 MA 6.51115 23 3.95124 5.52545 0.24196 6.75330 B 6.93020 23 0.26826 0.16491 0.00661 0.18354 DELTA 1.18912 23 4.21951 5.69036 0.24856 6.93684 MA 5.74108 24 3.78419 5.59842 0.67478 6.26453 B 6.45268 24 0.32668 0.17347 1.44970 0.52169 DELTA 0.39277 24 4.11087 5.42495 0.77493 6.78622 MA 6.84545 1 3.36730 6.13123 0.19077 6.75395 B 6.13708 1 0.54473 0.08538 0.79284 0.34637 DELTA 0.56569 1 3.91202 6.21661 0.98361 7.10031 MA 5.57139 3 2.83321 5.92158 1.89472 7.92524 B 6.30664 3 1.15577 0.64930 0.75686 1.58481 DELTA 1.95636 3 3.98898 6.57088 1.13786 6.34042 MA 4.35028 4 4.29046 5.73657 1.81816 7.02734 B 7.02882 4 0.14036 0.47000 0.26089 1.08028 DELTA 1.43858 4 4.43082 6.20658 1.55727 5.94705 MA 5.59024 5 3.93183 5.62762 1.70262 6.76859 B 6.11102 5 0.80437 0.67865 0.26531 0.29394 DELTA 0.94910 5 4.73620 6.30628 1.43731 6.47465 MA 5.16192 6 3.29584 5.47227 0.18852 6.49054 B 6.84279 6 0.16034 0.27073 0.16485 1.12558 DELTA 1.84288 6 3.13549 5.74300 0.02367 5.36496 MA 4.99991 8 3.25810 5.37064 0.09631 7.23131 B 7.16371 8 0.40547 0.13953 0.97906 0.62894 DELTA 2.15108 8 3.66356 5.23111 0.88274 6.60237 MA 5.01263 9 3.78419 5.94542 0.77839 5.86126 B 6.22910 9 0.64663 0.05847 0.42774 0.53530 DELTA 2.18430 9 4.43082 6.00389 0.35066 5.32595 MA 4.04480 10 4.07754 5.87493 2.32137 6.71736 B 6.59769 10 0.23995 0.00563 0.25309 0.00873 DELTA 0.75357 Patient No. E NE LF/HF LF Period VLF 10 4.31749 5.86930 2.06827 6.70863 MA 5.84412 11 4.33073 5.84064 2.89058 7.22570 B 5.76079 11 3.63759 0.01464 1.22533 1.33514 DELTA 0.55240 11 0.69315 5.82600 1.66525 5.89056 MA 5.20839 12 3.55535 6.04501 1.92977 8.50684 B 7.15797 12 0.13353 0.12041 0.15464 0.84735 DELTA 0.13525 12 3.68888 6.16542 1.77513 7.65949 MA 7.29322 13 3.33220 4.63473 0.11940 6.35464 B 6.76285 13 1.16761 1.05563 0.85621 0.63251 DELTA 0.52121 13 4.49981 5.69036 0.73681 6.98716 MA 6.24164 14 3.25810 5.96358 1.10456 7.01270 B 7.49426 14 * * 0.26353 1.20066 DELTA 3.15046 14 * * 1.36809 5.81204 MA 4.34381 15 5.42935 6.34564 2.76361 9.48594 B 7.05730 15 * * 1.14662 1.58468 DELTA 0.08901 15 * * 1.61699 7.90126 MA 6.96829 16 4.11087 6.59441 0.23319 6.68269 B 6.76872 16 0.06782 0.54941 0.34755 0.29398 DELTA 1.80868 16 4.04305 6.04501 0.11437 6.38871 MA 4.96004 17 * 6.28040 1.40992 6.09671 B 4.82671 17 * 0.12766 0.17490 0.05945 DELTA 0.69993 17 * 6.15273 1.23501 6.03726 MA 5.52665 18 2.39790 6.03548 0.23183 6.39707 B 6.60421 18 1.06784 0.11299 0.27977 0.38297 DELTA 1.92672 18 3.46574 6.14847 0.51160 6.01410 MA 4.67749 19 4.21951 6.35784 1.08183 5.54214 B 5.69070 19 0.21131 0.00347 0.12485 0.54440 DELTA 1.49802 19 4.43082 6.35437 1.20669 4.99774 MA 4.19268 20 4.14313 5.73334 0.89483 7.35045 B 6.93974 20 0.11778 0.00000 0.17129 0.58013 DELTA 1.72916 20 4.02535 5.73334 1.06612 6.77032 MA 5.21058 21 3.66356 6.06843 0.87315 5.09848 B 6.02972 21 0.20764 0.10485 0.41178 0.33378 DELTA 2.00974 21 3.87120 5.96358 0.46137 4.76470 MA 4.01998 22 3.29584 5.95324 2.38399 7.62877 B 7.54359 22 0.36772 0.68139 0.75014 0.89992 DELTA 1.25555 22 3.66356 6.63463 1.63384 6.72884 MA 6.28804