PubMed · 3066930
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M Hirakawa. 1988. [Hemodynamic changes in prone position].. https://pubmed.ncbi.nlm.nih.gov/3066930/
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It has been reported that there are differences in autonomic balance between Type As and Type Bs. This study evaluated the sympathovagal interaction in Type A (N = 10) and Type B (N = 10) male students during mental arithmetic task in a solo and a competitive condition by the spectral component analysis of heart rate variability (HRV). The low-frequency (LF) component to high-frequency (HF) component ratio was significantly greater in Type As than in Type Bs, though no significant differences were found in task performance, heart rate change, and blood pressure between the two subject groups in both conditions. The present findings indicate that there was a significant difference in sympathovagal balance between Type As and Type Bs, and that Type As showed dominant sympathetic activity. The results suggest that the power spectral analysis of HRV, which is convenient and non-invasive, has enough sensitivity to discriminate differences in autonomic balance between Type A subjects and Type B subjects, not only during the solo and competitive task period but also during the resting period.
Continuous heart rate recordings were obtained on elite American bi-athletes during competitions to provide a better understanding of the physiological demands of biathlon and the strategies used in approaching the shooting range. The findings demonstrate that the average age heart rate during skiing was approximately 90% of maximum heart rate. Heart rates decreased 10-12 bpm over a time period of approximately 50-60 sec during the approach to the firing line. At arrival to the firing line, heart rates were similar for prone and standing shooting averaging 85-87% of maximum heart rate. Mean minimum heart rates while at the firing line dropped to 61-73% of maximum heart rate and averaged approximately 20 bpm lower for prone shooting. The lower minimum heart rates during prone shooting were accounted for by the bi-athletes spending a longer time at the firing line and having a more rapid decrease in heart rate while in the prone position.
Oscillatory variations of cutaneous blood flow were studied using laser Doppler flowmetry in 20 newborns. Simultaneous monitoring of cardiorespiratory state was also performed. The frequency and amplitude of oscillatory curve varied, even on identical skin regions in each infant. When their respiration and heart rate were irregular, the frequencies of oscillatory curves were significantly higher and with a larger amplitude than when cardiorespiratory function was regular. The frequencies of oscillatory curves at two symmetrical points of an individual were not different, but a significant difference in the oscillatory cycle was recognized at two asymmetrical points. Distributions of peak-to-peak time periods of oscillatory curves were studied in nine healthy and four sick newborns. Seven of nine healthy newborns had more than two peaks in their distributions, while only one peak with a narrowly-spread distribution was observed in the four sick newborns with almost exclusively periodic breathing throughout monitoring. In conclusion, we speculate that cardiorespiratory state and some neurogenic control affects the variations observed. In addition, the narrowly-spread distribution of each time period appeared to be an important indicator of morbidity.