Association between psychological and cardiac functioning in a confined population
Besides weightlessness, inactivity is likely to play a role in cardiovascular deconditioning during long duration missions. Moreover, confinement of a crew in a limited space for a long period of time, as envisaged for the Mars 500 simulation, could produce emotional stress which could in turn lead to altered cardiovascular function and undermine the wellbeing of the crew.
In normal circumstances our heart rate is influenced by the sympathetic and parasympathetic nervous systems, which in basic terms influence accelerated and decelerated bodily activities respectively. They determine our heart rate and strength of contraction and adapt these to different needs during our daily activities. The control of our heart rate receives important feedback information by the baroreflex mechanism (the relationship between heart rate and blood pressure). This monitors our blood pressure and adjusts heart rate to maintain a stable blood pressure within healthy limits.
This study will evaluate the effect of confinement and isolation on changes in the psychological wellbeing of the Mars 500 crew and try to correlate any mood changes with changes in cardiac regulation and cardiopulmonary function. The psychological evaluation of mood alterations will be assessed through questionnaires filled out by the crew. This will be correlated with different physiological measurements. 24-hr ECG data will come from a portable Holter device, and additional short-duration ECG and blood pressure measurements will be taken. Spectral analysis will be used to determine circadian rhythms and sleep alterations, heart rate and blood pressure variability, the baroreflex and synchronization of cardiac activity and respiration. Additional cardiac function data will be obtained using tele-echocardiography and tele-auscultation, which will give some insight into heart mechanics (echo) and hemodynamics (heart sounds).
Science Team: Andre Aubert (BE) et al.