RESUMO OBJETIVOS: Os efeitos do teste ortostático sobre o sistema cardiovascular já foram investigados, mas não há dados sobre o comportamento dos índices geométricos de variabilidade da frequência cardíaca. Aqui, foram avaliados os efeitos do teste ortostático ativo nos índices geométricos de variabilidade da frequência cardíaca em mulheres. MÉTODO: O estudo foi realizado em 12 mulheres saudáveis com idades entre 18 e 30 anos. Para a análise da variabilidade da frequência cardíaca, este parâmetro foi registrado batimento a batimento. Os intervalos RR foram transformados em figuras geométricas e, a partir destas, foi calculado o índice triangular, a interpolação triangular dos intervalos RR, o SD1, SD2 e a relacão SD1/SD2, que foram obtidos a partir da plotagem de Poincaré. A análise visual do gráfico foi também realizada. Para o teste, os participantes levantaram-se rapidamente de uma posicão sentada (em 3 segundos ou menos) e permaneceram imóveis, de pé, por 15 minutos. Amostras de variacão de frequência cardíaca foram coletadas em quatro momentos: repouso, 0-5 minutos, 5-10 minutos e 10-15 minutos a pé. RESULTADOS: O índice triangular, a interpolacão triangular dos intervalos RR, o SD1 e SD2 índices apresentaram-se reduzidos (p < 0,05) no intervalo 10-15 minutos depois de os voluntários se levantarem. A relacão SD1/SD2 apresentou-se reduzida durante o intervalo 0-15 minutos depois dos participantes passarem à posicão ortostática. CONCLUSÃO: Os índices geométricos de variabilidade da freqüência cardíaca diminuiram em resposta ao teste ortostático ativo em mulheres saudáveis.

OBJECTIVES: The effects of the orthostatic test on the cardiovascular system have been investigated, but there are no data on the behavior of the geometric indices of heart rate variability. We evaluated the effects of the active orthostatic test on the geometric indices of heart rate variability in women. METHOD: The study was performed on 12 healthy women between ages 18 and 30. For the analysis of heart rate variability, heart rate was recorded beat-to-beat. The RR intervals were transformed into geometric figures, and from these we calculated the triangular index, the triangular interpolation of RR intervals, the SD1, SD2 indexes and the SD1/SD2 ratio, which were obtained from the Poincare´ plot. Visual analysis of the plot was also performed. For the test, participants quickly stood up from a seated position in 3 seconds or less, and remained standing still for 15 minutes. Heart rate variability samples were collected at four moments: rest, 0-5 minutes, 5- 10 minutes and 10-15 minutes at standing position. RESULTS: The triangular index, the triangular interpolation of RR intervals, the SD1 and SD2 indices were reduced (p < 0.05) at 10-15 minutes after the volunteers stood up from seated position. The SD1/SD2 ratio was decreased at 0-15 minutes after the subjects changed from seated to orthostatic position. CONCLUSION: The geometric indices of heart rate variability decreased in response to the active orthostatic test in healthy women.

OBJECTIVES: There are no data in the literature with regard to the acute effects of different styles of music on the geometric indices of heart rate variability. In this study, we evaluated the acute effects of relaxant baroque and excitatory heavy metal music on the geometric indices of heart rate variability in women. METHODS: We conducted this study in 21 healthy women ranging in age from 18 to 35 years. We excluded persons with previous experience with musical instruments and persons who had an affinity for the song styles. We evaluated two groups: Group 1 (n = 21), who were exposed to relaxant classical baroque musical and excitatory heavy metal auditory stimulation; and Group 2 (n = 19), who were exposed to both styles of music and white noise auditory stimulation. Using earphones, the volunteers were exposed to baroque or heavy metal music for five minutes. After the first music exposure to baroque or heavy metal music, they remained at rest for five minutes; subsequently, they were re-exposed to the opposite music (70-80 dB). A different group of women were exposed to the same music styles plus white noise auditory stimulation (90 dB). The sequence of the songs was randomized for each individual. We analyzed the following indices: triangular index, triangular interpolation of RR intervals and Poincaré plot (standard deviation of instantaneous beat-by-beat variability, standard deviation of the long-term RR interval, standard deviation of instantaneous beat-by-beat variability and standard deviation of the long-term RR interval ratio), low frequency, high frequency, low frequency/high frequency ratio, standard deviation of all the normal RR intervals, root-mean square of differences between the adjacent normal RR intervals and the percentage of adjacent RR intervals with a difference of duration greater than 50 ms. Heart rate variability was recorded at rest for 10 minutes. RESULTS: The triangular index and the standard deviation of the long-term RR interval indices were reduced during exposure to both music styles in the first group and tended to decrease in the second group whereas the white noise exposure decreased the high frequency index. We observed no changes regarding the triangular interpolation of RR intervals, standard deviation of instantaneous beat-by-beat variability and standard deviation of instantaneous beat-by-beat variability/standard deviation in the long-term RR interval ratio. CONCLUSION: We suggest that relaxant baroque and excitatory heavy metal music slightly decrease global heart rate variability because of the equivalent sound level.