Marck, Jan Willem

BACKGROUND Psycho‐socio stressors may over time result in dominance of the sympathetic nervous system (SNS) over the parasympathetic nervous system (PNS). Reduced PNS control over cardiovascular processes has been associated with decreased health. Heart rate variability (HRV) has been proposed as a technique to quantify SNS and PNS interactions and thus might offer a noninvasive predictive index. OBJECTIVE To investigate the impact of real‐life stressors on HRV fluctuations in independent living elders (EL). METHODS For three months every two weeks EL (N=22; Age=75±9; M/F ratio=17/5) performed autonomic tests consisting of quiet breathing, paced breathing and hand grip. All did a questionnaire assessing depression, positive/negative live events, and isolation. RESULTS Negative events (r=0.36, p=.01) and isolation (r=0.35, p=0.02) are correlated with HR. Personal changes in HRV, SDNN (r=−0.43, p<0.005) and Poincare Width (r= −0.42, p<0.005), are correlated to negative life events. CONCULSION Negative life events reduce HRV which suggests either SNS activation and/or PNS withdrawal. Research was made possible by Healthy for Life, TNO, and the Center for Innovation, Mayo Clinic.

BACKGROUND Exposure to high altitude (HA) results in sympathetic nervous system (SNS) activation. This might interact with HA related illness. HRV is a technique to quantify SNS and parasympathetic nervous system (PNS) interactions and thus offers a noninvasive index in extreme environments. OBJECTIVE To quantify the changes in HRV in elite athletes (AT), acclimatized for 2 mo. at Everest base camp (BC) prior to summiting, relative to a control group (CT) (climbing and acclimatizing to BC in 3 wks). METHODS AT (N=4, Age=35±10 y, BMI=22±2, M/F ratio 2/2) and CT (N=8, Age=35±10 y, BMI=26±2, M/F ratio 8/0) performed autonomic tests consisting of quiet breathing, paced breathing prior to, mid‐way at BC and at 2 wks post expedition. RESULTS At BC, AT had (compared to CT) higher HR (p=0.07) and reduced HRV (SDNN, p=0.09). For AT and CT combined: measures of HRV were reduced at BC (SDNN, p=0.05, Poincare length, p=0.05) and remained below baseline 2 wks post climb (SDNN, p=0.01; PCL, p=0.01). CONCULSION HRV is reduced with HA exposure in both AT and CT and remains reduced 2 wks post exposure, suggesting either SNS activation and/or PNS withdrawal. FUNDING : Mayo Clinic & The North Face.

The steadily growing elderly population calls for efficient, reliable and preferably ambulant health supervision. Since cardiovascular risk factors interact with psychosocial strain (e.g., depression), we investigated the potential contribution of psychosocial factors in discriminating generally healthy elderly from those with a cardiovascular condition, on and above routinely applied physiological assessments. Fifteen elderly (aged 60 to 88) with a cardiovascular diagnosis were compared to fifteen age and gender matched healthy peers. Six sequential standardized lab assessments were conducted (one every two weeks), including an autonomic test battery, a 6-min step test and questionnaires covering perceived psychological state and experiences over the previous two weeks. Specific combinations of physiological and psychological factors (most prominently symptoms of depression) effectively predicted (clinical) cardiovascular markers. Additionally, a highly significant prognostic model was found, including depressive symptoms, recently experienced negative events and social isolation. It appeared slightly superior in identifying elderly with or without a cardiovascular condition compared to a model that only included physiological parameters. Adding psychosocial parameters to cardiovascular assessments in elderly may consequently provide protocols that are significantly more efficient, relatively comfortable and technologically feasible in ambulant settings, without necessarily compromising prognostic accuracy.