Dynamics of the RR-interval versus blood pressure relationship at exercise onset in humans
| Autor: | Frédéric Lador, Aurélien Bringard, Guido Ferretti, Alessandra Adami, Timothée Fontolliet, Enrico Tam, Nazzareno Fagoni, Christian Moia |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Male
Cardiac output baroreflex resetting Supine position Physiology Blood Pressure 030204 cardiovascular system & hematology 0302 clinical medicine heart rate Orthopedics and Sports Medicine Cardiac Output Exercise transients ddc:617 musculoskeletal neural and ocular physiology Baroreflex resetting Baroreflex sensitivity Heart rate Mean arterial pressure Peripheral resistance Adult Exercise Female Humans Posture Baroreflex Public Health Environmental and Occupational Health Physiology (medical) General Medicine baroreflex sensitivity Pulse pressure Anesthesia Cardiology mean arterial pressure peripheral resistance Public Health exercise transients medicine.medical_specialty 03 medical and health sciences Internal medicine medicine business.industry Environmental and Occupational Health Light Exercise 030229 sport sciences Blood pressure business human activities |
| Zdroj: | European Journal of Applied Physiology, Vol. 117, No 4 (2017) pp. 619-630 |
| ISSN: | 1439-6319 |
| Popis: | PURPOSE: The dynamics of the postulated phenomenon of exercise baroreflex resetting is poorly understood, but can be investigated using closed-loop procedures. To shed light on some mechanisms and temporal relationships participating in the resetting process, we studied the time course of the relationship between the R-R interval (RRi) and arterial pressure with a closed-loop approach. METHODS: On ten young volunteers at rest and during light exercise in supine and upright position, we continuously determined, on single-beat basis, RRi (electrocardiography), and arterial pressure (non-invasive finger pressure cuff). From pulse pressure profiles, we determined cardiac output (CO) by Modelflow, computed mean arterial pressure (MAP), and calculated total peripheral resistance (TPR). RESULTS: At exercise start, RRi was lower than in quiet rest. As exercise started, MAP fell to a minimum (MAPm) of 72.8 ± 9.6 mmHg upright and 73.9 ± 6.2 supine, while RRi dropped. The initial RRi versus MAP relationship was linear, with flatter slope than resting baroreflex sensitivity, in both postures. TPR fell and CO increased. After MAPm, RRi and MAP varied in opposite direction toward exercise steady state, with further CO increase. CONCLUSION: These results suggest that, initially, the MAP fall was corrected by a RRi reduction along a baroreflex curve, with lower sensitivity than at rest, but eventually in the same pressure range as at rest. After attainment of MAPm, a second phase started, where the postulated baroreflex resetting might have occurred. In conclusion, the change in baroreflex sensitivity and the resetting process are distinct phenomena, under different control systems. |
| Databáze: | OpenAIRE |
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