A correlation between GDV and heart rate variability measures
GDV and heart rate variability
This study [Cioca G, et.al. 2004] was an extension of the studies previously presented [Bundzen, 2002; Korotkov, 2002; Buyantseva, 2003]. The control subjects (n=24) from that study were volunteers from the State Medical Academy in Russia and were used for the Orthostatic test. Fourty-three athletes (age 19-24) from the State Research Institute of Sport in Russia volunteered for the exercise tests.
Heart Rate Variability (HRV). HRV measures were recorded using a traditional electrocardiogram with four leads attached to the left + right hands and the left + right ankles. HRV was calculated using the NeuroSoft Company (Russia) and Polar Electro (Finland) Software. Heart Rate (HR) was calculated using following formula: HR= 60×103 msec/R- R, where R-R is the average length in seconds of the R-R intervals (RRNN) for each group. Two parameters were calculated from the time domain measures of R-R interval variability. The standard deviation of R- R intervals (SDNN) can be used as a measure of sympathetic nervous activity, whereas the root-mean square of successive differences in R-R intervals (RMSSD) reflects parasympathetic activity.
Spectral analysis of time domain curves reveals peaks in the very low frequency range (VLF: 0.004-0.04 Hz), the low-frequency range (LF: 0.04- 0.15 Hz) and the high frequency range (HF: 0.15-0.5 Hz). LF/HF is the ratio of the low / high frequency power components. The VLF parameter is believed to measure the hormonal regulation (with some sympathetic nervous system activity), the LF parameter is a measure of the sympathetic nervous system and the HF parameter is a measure of the activity of the parasympathetic system.
Background HRV and GDV measures were taken after 5 minutes of resting in a quiet room. In addition HRV and GDV measures were also taken following the three experimental conditions. For the Orthostatic test, subjects were asked to deep breathe in a supine position for 5 minutes (controlled breathing involved 6 breaths per minute with 5 second inhalations and 5 second exhalations). Then subjects stood up and resumed regular tidal breathing. After 5 minutes GDV and HRV measures were obtained.
Electrophotonic Analysis in Medicine
The exercise test involved 10 minutes of strenuous physical exercise before GDV and HRV measures were obtained. The third experimental condition was the consumption of dark chocolate, three hours after which GDV and HRV measures were taken. Correlation coefficients were calculated for GDV and HRV results obtained during the background and during the three experimental conditions. In addition to analysis of individual sessions, the difference between the orthostatic and background tests was calculated. Significant correlations were seen using GDV parameters from individual fingers (eg 5R), for differences between two fingers (eg. 5L-5R) or by using all 10 fingers (eg. deviations in absolute values, or mathematical combinations of all ten (stress index). Two GDV parameters (stress index and area) correlate with a balanced sympathetic and parasympathetic regulation of HRV. The same balanced regulatory state has been previously reported for other positive emotional stimuli (McCraty, 1995).
In the present study, despite the parasympathetic dominance associated with exercise, the sympathetic component of HRV (LF) was correlated with the stress index parameter of GDV. Thus the sympathetic nervous activity appears to best correlate with GDV parameters in two different experimental conditions controlled by either sympathetic or parasympathetic activity.
In conclusion HRV and GDV were correlated in a non-diseased population under different physiological conditions. In situations where either the sympathetic or the parasympathetic nervous systems were activated, the HRV parameter corresponding to sympathetic regulation of heart rate was correlated with GDV. In a situation inducing a positive emotional state, the HRV parameter which correlates with GDV is the balance between the sympathetic and parasympathetic nervous systems. In all cases, GDV entropy correlated with the different HRV parameters. Since these HRV parameters reflect involuntary reactions of the heart to psycho-physical loading, the observed correlation between HRV and GDV allows the conclusion that well being can be measured as a resilience to psycho-physical stimuli.
In another research 60 athletes in the age of from 18 till 23 years, among them 30 wrestlers of high qualification took part [Lovygina 2005]. GDV and HRV parameters were measured both in initially and after the loading. Significant correlations between respiratory waves (RW) and GDV area (r = – 0.70 p < 0.05) and sluggish waves of the 1st order (SW-1) (r = – 0.69 p < 0.05) was found.
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