INTERRELATION BETWEEN HEART RATE AND MENTAL WORK AFTER PHYSICAL LOAD

The attitude towards the functional activity of the heart has been changing recently. While contracting the heart is supposed not only to guarantee bloodstream circulation but also to send nervous, hormonal and electromagnetic information, to interrelate the body, the mind, emotions and spirit (Lacey J., Lacey B., 1978; Armor, Ardel, 1994; Goleman, 1995; Childre, Martin, 1999). It was found that the heart rate and its variability sensitively responded to the mental load (Hjortskov et al., 2004; Wand et al., 2005). The changes in the heart during and after the physical load is a question of detailed discussion in literature, but there are few studies on the changes in the heart rate during mental work after the physical load has been applied. The aim of research was to establish the links between the changes in the heart rate variability and the level of mental working capacity after standardized physical load of athletic and non-athletic females. Ten athletic and eight nonathletic females participated in the research. The mean age of the research participants was 23. The study was carried out in the “Center for Research of Human Physical Abilities” at the Lithuanian Academy of Physical Education in 2003. During the research the data were registered as a continuous electrocardiogram with RR intervals, using a special computer program (Vainoras, 2002). We analyzed the indicators of the heart rate and its variability: the median of heart RR intervals in ms; standard heart RR intervals variability in ms — RR dispersion, ms; the percentage of standard heart rate variability — RR dispersion, %; heart rate variability RRj after comparing the duration of heart cycles in ms — RR (j + 1) dispersion, ms; heart rate variability δ (RRj) after comparing the duration of heart cycles in percent — RR ( j + 1) dispersion, %. The research participants performed a mental work test before and after the standardized physical load (150 W) (Grinienė, Vaitkevičius, 1998). We considered the following mental work parameters: work intensity (the number of reviewed signs), accuracy of work (the number of mistakes) and the effi ciency coeffi cient Q which was estimated using the formula Q = (i / 10) / (i / 10) + a, where i — the number of reviewed signs, a — the number of mistakes. Results. It was found that the indicators of the heart rate and its variability in both groups before the physical load were similar. The mental work indicators before the physical load in both groups were similar too because the work was of the same intensity and accuracy. After the physical load athletic females recovered their usual heart rate and its variability sooner compared to non-athletic females (p < 0.05), their mental work indicators were signifi cantly higher while the indicators of the mental in the group of non-athletic females remained unaltered. The results of the research revealed that athletic females possessed better functional activity of the heart after the physical load which favorably affected their mental work. The lower functional activity of the heart in the group of non-athletic females affected their performance in the test of mental work.