Document Detail

Estimation of the lactate threshold from heart rate response to submaximal exercise: the pulse deficit.
MedLine Citation:
PMID:  17111313     Owner:  NLM     Status:  MEDLINE    
In this study, we evaluated the validity of a sharp increase in pulse deficit (PD) as a noninvasive index for estimation of the first lactate threshold (LT (1)) in healthy individuals with various levels of aerobic fitness. Three groups of healthy male subjects participated in the study: 15 sedentary individuals, 14 students of physical education, and 13 competitive athletes. Each subject performed a maximal incremental exercise test on the cycle ergometer for the determination of the LT (1), the second lactate threshold, and peak power output. On different days, subjects performed several 8-min bouts of constant-load exercise on the cycle ergometer, corresponding to each of the power outputs of the maximal test, to evaluate PD, which was calculated as the total number of heart beats of the last 4 min minus the total number of heart beats in the first 4 min of exercise. The three groups presented similar blood lactate, heart rate and pulse deficit responses to exercise. For the first power output up to the LT (1), PD showed no significant changes. For the three groups, a sharp increase in PD was seen at the intensity immediately above LT (1). There was a significant correlation between PD and blood lactate changes from the rest to 4th min of submaximal exercise (r = 0.83, p < 0.05). The power output before a sharp increase in PD detected during constant-load exercise (112 +/- 38 W) and the power output corresponding to the LT (1) detected during the incremental test (111 +/- 37 W, p = 0.323) were similar and strongly correlated (r = 0.99, p = 0.0001). The absolute cut-point value of 25 beats for PD had a sensitivity of 100 %, a specificity of 95 %, and a positive predictive value of 90 % for the detection of LT (1). The determination of PD provides an accurate noninvasive estimate of the LT (1) in healthy young men with different levels of fitness. One 8-min submaximal exercise bout can establish if an individual is exercising above or below the LT (1).
B T Roseguini; F Narro; A R Oliveira; J P Ribeiro
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Publication Detail:
Type:  Journal Article     Date:  2006-11-16
Journal Detail:
Title:  International journal of sports medicine     Volume:  28     ISSN:  0172-4622     ISO Abbreviation:  Int J Sports Med     Publication Date:  2007 Jun 
Date Detail:
Created Date:  2007-06-01     Completed Date:  2007-08-15     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8008349     Medline TA:  Int J Sports Med     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  463-9     Citation Subset:  IM    
Cardiology Division, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos 2350, Porto Alegre, RS 90035-007, Brazil.
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MeSH Terms
Anaerobic Threshold / physiology*
Exercise / physiology*
Exercise Test
Heart Rate / physiology*
Lactic Acid / analysis*,  blood,  metabolism
Physical Exertion / physiology*
Reg. No./Substance:
50-21-5/Lactic Acid

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