Heart rate at 4 s after the onset of exercise in endurance-trained men.
It has been suggested that the increase in heart rate (HR) at the onset of exercise is caused by vagal withdrawal. In fact, endurance runners show a lower HR in maximum aerobic tests. However, it is still unknown whether endurance runners have a lower HR at 4 s after the onset of exercise (4th-sec-HR). We sought to measure the HR at the onset of the 4 s exercise test (4-sET), clarifying its relationship to heart rate variability (HRV), spectral indices, and cardiac vagal index (CVI) in endurance runners (ER) and healthy untrained controls (CON). HR at 4th-sec-HR, CVI, and percent HR increase during exercise were analyzed in the 4-sET. High frequency spectrum (HF-nu), low frequency spectrum (LF-nu), and low frequency/high frequency band ratio (LF/HF) were analyzed from the HRV. ER showed a significantly higher HF, and both a lower LF and LF/HF ratio compared with the CON. ER presented a significantly lower 4th-sec-HR, although neither CVI nor HR increases during exercise were statistically different from the CON. In conclusion, ER presented a lower 4th-sec-HR secondary to increased vagal influence over the sinus node. CVI seems to be too weak to use for discriminating individuals with respect to the magnitude of HR vagal control.
['Zaniqueli|Divanei|D|', 'Morra|Elis Aguiar|EA|', 'Dantas|Eduardo Miranda|EM|', 'Baldo|Marcelo Perim|MP|', 'Carletti|Luciana|L|', 'Perez|Anselmo José|AJ|', 'Rodrigues|Sérgio Lamêgo|SL|', 'Mill|José Geraldo|JG|']
D000328:Adult D001794:Blood Pressure D016022:Case-Control Studies D003430:Cross-Sectional Studies D015444:Exercise D005080:Exercise Test D006339:Heart Rate D006801:Humans D008297:Male D010807:Physical Endurance D013997:Time Factors D014630:Vagus Nerve
heart rate vagal withdrawal endurance runners 4 s exercise test heart rate variability coureurs de fond exercice physique physical exercise retrait vagal rythme cardiaque test de l’exercice de 4 secondes variabilité du rythme cardiaque