Assessment of the adaptive state of students based on the analysis of heart rate variability indicators

In the course of the study, the adaptive state of VlSU students was assessed by temporal, spectral, cardiointervalographic and integral indicators of heart rate variability. The characteristic of the state of the regulatory systems of students is given. The obtained results can serve as a certain addition to the understanding of the peculiarities of the process of adaptation of young students in the conditions of studying at higher school. Key words: heart rate variability (HRV), students, adaptation, regulatory systems, sympathetic and parasympathetic influence.

Features of changes in heart rate variability indices in driving school cadets with different levels of preparedness

The research was carried out on two independent experimental groups of boys and girls. The first was observed in traffic conditions, the second during the period of auto-simulator training. The HRV indices were determined: HR - heart rate, IN - index of tension of regulatory systems, AMo - amplitude of the mode, LF/HF - index of vagosympathetic interaction. A pronounced sympathetic reaction of more prepared cadets to the training load with the subsequent restoration of the studied characteristics was revealed. Key words: heart rate variability, autonomic regulation, vagosympathetic interaction, driver training, level of preparedness.

Assessment of the functional state of military men with different types of autonomic regulation in the midland’s conditions

The article presents the results of assessment and dynamic control over the functional state of military men in the midlands conditions. Depending on the initial type of autonomic regulation, groups with vagotonic (24%), sympatotonic (26%) and normotonic (50%) directions of regulatory processes were identified. It has been established that the state of optimal working voltage with more economical functioning of regulatory mechanisms is characteristic of carriages; for sympathotonics - an overstrain of regulatory mechanisms, and for normotonics - a moderate tension of regulatory systems with the mobilization of the functional reserves of the body. Key words: heart rate variability, functional state, types of autonomic regulation, midlands, military men.

Blunted Cardiac Autonomic Responsiveness to Hypoxemic Stress in Healthy Older Adults

Supine resting cardiac dynamics and responses to steady-state hypoxemia were investigated in six healthy older (59-72 yrs) adults using coarse-graining spectral analysis of heart rate variability (HRV) and were compared to six young (22-29 yrs) adults studied previously (Lucy et al<normal + trebuchet ms char,12 pt char, black char, condensed by 0.05 pt char>.,</normal + trebuchet ms char,12 pt char, black char, condensed by 0.05 pt char> 2000). End-tidal carbon dioxide pressure (PETCO2) was clamped at 1-2 mmHg above the usual resting value for 11 min of euoxia (PETO2100 mmHg), followed by 22 min of hypoxia (PETO2 55 mmHg). During euoxia, vagally mediated harmonic and fractal power of HRV of older adults was minimal. Hypoxia induced an increase in ventilation, p < 0.01, and heart rate, p < 0.05. The heart rate increase (mean ± SE) of 0.23 ± 0.08 beats•min−1 per 1% decrease in arterial O2 saturation was 25% of that demonstrated previously by young subjects, p < 0.001. In older adults, HRV spectral power remained unchanged during hypoxia, providing further evidence of an age-related blunting of cardiac autonomic function. Key words: heart rate variability, coarse-graining spectral analysis, cardiac vagal control, acute isocapnic hypoxia, dynamic end-tidal forcing (DEF) technique

Validation of a heart-rate monitor for measuring a stress response in dairy cows

In three experiments, a commercial non-invasive heart-rate monitor, Polar® Sport Tester (PST), was validated for use with dairy cows. First, 10 monitors were tested using a pulse generator, which produced pulses at levels between 30 and 240 bpm. PST values and generated beats were highly correlated (r = 0.97) but with varying delay (5–55 s), depending on pulse-rate level.In a second experiment, 10 dairy cows were quietly standing or exercising on a treadmill while their heart rates were recorded by direct-wire electrocardiograph (ECG) as well as the PST. Correlations between ECG and PST values during standing (0.88) and exercising (0.72) were significant and differed between cows. During standing, inter-beat interval and PST standard deviations were significantly correlated (Rsp = 0.76), as were their coefficients of variation (Rsp = 0.89).The third experiment showed that the heart rate of 10 dairy cows increased rapidly immediately after an individual was isolated from the herd. Cows showed no obvious signs of being hampered by the equipment during the 1-h trials.Change in heart rate may be a relevant parameter for studying an animal's response to a stressor. As heart-rate variability is thought to serve as an important mechanism for adaptability in humans, this aspect needs further attention in farm animals. The PST is suitable for measuring both heart rate and heart-rate variability in dairy cows. Key words: Heart rate, dairy cows, stress, treadmill