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Central Hemodynamic Response to Acute Sympathetic Activation via Cold Pressor Test in Healthy Aging
Author(s) -
Pearson James,
Borner Anastasiya,
Murray Kyle
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.1056.8
Subject(s) - cold pressor test , medicine , arterial stiffness , heart rate , pulse wave velocity , blood pressure , cardiology , hemodynamics , sphygmomanometer , anesthesia , mean arterial pressure , photoplethysmogram , supine position , myocardial infarction , filter (signal processing) , computer science , computer vision
The incidence of cardiovascular related events, such as myocardial infarction and stroke, increase in aged individuals. This cardiovascular risk is elevated further during the winter months when environmental temperatures decrease. Increased sympathetic nerve activity accompanies decreases skin surface temperature. This increase in sympathetic nerve activity may have implications for the control of central hemodynamics and arterial stiffness. We aimed to investigate the influence of acute sympathetic activation via cold pressor test upon central hemodynamics and arterial stiffness in young and healthy aged individuals. Eleven young (Young: 7 males, 27±7yrs, 175±9cm, 77.4±13.8 kg) and eleven healthy aged individuals (Aged: 6 males, 57±12 yrs, 172±8 cm, 75.8±23 kg) completed a cold pressor test (CPT) where the left hand was immersed up to the wrist in 2–4°C water for 3 minutes while supine. All participants were free of cardiovascular acting medications and disease. Central hemodynamics and arterial stiffness, including subendocardial viability ratio (SEVR %), were estimated via radial tonometry linked to software with a generalized transfer function (SphygmoCor®, AtCor Medical). Aortic pulse wave reflection was referenced to a heart rate of 75 bpm (augmentation index; Aix75; %). Aortic pulse wave velocity (aPWV; m/s) was estimated using an automated sphygmomanometer (Mobil‐O‐Graph®; I.E.M). Mean arterial pressure (MAP; mmHg) and heart rate (HR; bpm) were estimated using photoplethysmography (NexFin®, BMEYE). Measurements were obtained at baseline prior to, during and at the end of the cold pressor test. Baseline MAP was not different between Young and Aged (90±10 vs. 91±10 mmHg, P > 0.05). Baseline AIx75 and aPWV were both different between Young and Aged (AIx75: −2±16 vs. 15±9% and aPWV: 5.4±0.6 vs.7.9±1.4 m/s, both P < 0.01). At the end of CPT, MAP increased relative to baseline in both Young and Aged (106±8 and 106±11 mmHg; both P < 0.01) but was not different between groups (P > 0.05). At the end of CPT AIx75 increased relative to baseline in both Young (+18±13% to 15±14%, P = 0.0003) and Aged (+12±6% to 26±7%; P = 0.0001). AIx75 was higher in the aged individuals at the end of the cold pressor test (P = 0.027). Relative to baseline SEVR was unchanged at the end of CPT in Young (150±35 to 155±42%; P > 0.05) but decreased in Aged (157±26 to 135±36%; P = 0.0055). Acute sympathetic activation via cold pressor test resulted in a greater aortic pulse wave reflection and reduced subendocardial viability ratio in healthy aged relative to young individuals. This suggests that acute sympathetic activation increases myocardial strain and may help explain the increased incidence of myocardial infarction in aged individuals during winter months.