title: [Effect of muscle contraction on heart rate and skin blood flow. Preliminary results].
abstract: Evaluation of heart rate variability is an important tool to study several diseases. The most important tests include the variability of the heart rate as a function of time and as function of frequency, variability of blood pressure and pulsatile cutaneous blood flow (PCBF). We studied the effect of a sustained contraction of the quadriceps muscle on the instantaneous heart rate and pulsatile cutaneous blood flow in 10 healthy subjects. We measured the R-R interval and the instantaneous heart rate, in the time domain, 10 beats before the contraction, the R-R interval that coincided with the onset of the contraction, and the 30 R-R intervals after the beginning of the contraction. To measure the PCBF we used a photopletismograph designed for this purpose. We recorded the surface electromyographic activity (EMG) of the quadriceps muscle to determine the onset and end of the muscle contraction, and measured respiratory movements with a belt. We found an increase of the instantaneous heart rate at the first and second beats after the onset of the contraction. There was a decrease of the pulsatile cutaneous blood flow of the finger pad immediately after the contraction, which lasted for approximately eight beats. The findings support the idea of a central command and co-activation of the motor and sympathetic nervous systems. This efferent sympathetic activity seems to act not just on the contracting muscle but also on the heart and the cutaneous blood vessels of the extremities. These findings imply that it is quite likely that the sympathetic efferent effect has a supraspinal origin. This is a test that could be used to study cardiovascular control by the sympathetic nervous system.
authors.affiliation: Departamento de Neurología y Psiquiatría, Laboratorio de Neurofisiología Clínica, Instituto Nacional de Ciencias Médicas y Nutrición Dr. Salvador Zubirán Vasco de Quiroga No. 15 Tlalpan D.F. 14000. noelplascencia@yahoo.com.mx
authors.forename: Noel Isaías
authors.initials: NI
authors.lastname: Plascencia-Alvarez
authors.forename: Bruno
authors.initials: B
authors.lastname: Estañol
authors.forename: Marco Vinicio
authors.initials: MV
authors.lastname: Corona Figueroa
authors.forename: Benita
authors.initials: B
authors.lastname: Mondragón
authors.forename: María Magdalena
authors.initials: MM
authors.lastname: López-Lomelí
authors.forename: Luis
authors.initials: L
authors.lastname: Espinosa-Sierra
authors.forename: Jaime
authors.initials: J
authors.lastname: Ruiz
authors.forename: Guillermo
authors.initials: G
authors.lastname: García-Ramos
authors.forename: Oscar
authors.initials: O
authors.lastname: Infante
authors.forename: Raúl
authors.initials: R
authors.lastname: Martínez Memije
mesh_terms: D000328:Adult; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D012039:Regional Blood Flow; D012867:Skin / Q000098:blood supply*
vernacular_title: Efecto de la contracción muscular en la frecuencia cardiaca y en el flujo sanguíneo cutáneo. Resultados preliminares.