Heart-Rate Variability and Blood-Lactate Threshold Interaction During Progressive Resistance Exercise in Healthy Older Men

Abstract

The objective of this study was to (a) evaluate the impact of the leg press, at variable percentages of 1 repetition maximum (1RM), on heart rate variability (HRV) and blood lactate and (b) determine the relationship between HRV with blood lactate in a healthy elderly cohort. Ten healthy men (64 +/- 4 years) participated in a progressive leg-press protocol to maximal exertion. Initially, 1RM for the leg press was determined for all subjects. The protocol then began at 10% of 1RM, with subsequent increases of 10% until 30% of 1RM, followed by incremental adjustments of 5% until exhaustion. The measurement of instantaneous R-R interval variability from Poincare plots (SD1 and SD2) and time domain indexes (RMSSD and RMSM), blood pressure, and blood lactate were obtained at rest and all leg-press loads. Significant alterations of HRV and blood lactate were observed from 30% of 1RM leg press (p < 0.05). Additionally, significant correlations were found between the lactate threshold (LT) and the RMSSD threshold (r = 0.78; p < 0.01), and between the LT and SD1 threshold (r = 0.81, p < 0.01). We conclude that metabolic and cardiovascular alterations are apparent during relatively low resistance exercise (RE) loads in apparently healthy subjects. In addition, HRV indexes were associated with blood-lactate levels during RE. The practical applications is the possibility of using HRV as a noninvasive measure obtained at a relatively low cost may be used to identify neural and metabolic alterations during RE in older subjects.

Cardiac autonomic modulation during progressive upper limb exercise by patients with coronary artery disease

“…The progressive decrease in this index beginning at 30% 1RM in both groups can be explained by a decrease in parasympathetic modulation and, consequently, a predominance of sympathetic modulation at higher intensities (6). Similarly, Simões et al (12) observed a significant decrease in SD1 and rMSSD indexes beginning at 30% 1RM in leg resistance exercise that was related to lactate accumulation. They concluded that this intensity (30% of 1RM) was associated with the point at which aerobic metabolism becomes supplemented by anaerobic metabolism.…”

“…However, to our knowledge, autonomic nervous control during RE has been little studied. Specifically, Simões et al (12) studied the behavior of cardiac autonomic modulation during leg press RE, which is common in fitness centers and rehabilitation programs. They found that systolic blood pressure (SBP), HR and blood lactate were significantly increased, but that HR variability (HRV) indexes such as root mean square of successive differences (rMSSD) and the standard deviation of the instantaneous beat-to-beat R-R interval variability (SD1) (parasympathetic markers) decreased at peak exercise load when compared to resting values.…”

Efeito agudo da intensidade do exercício de força na modulação autonômica cardíaca pós-exercício

“…A recent study 12 showed that performing exercises only for the lower limbs improves the cardiac sympathovagal balance after exercise. However, the impact of exercises for the trunk and upper limbs in these responses has not been studied.…”

Resistance Training and Autonomic Modulation in the Elderly

“…It has been observed in the elderly that reducing the vagal component during resistance exercise (RE) reaches a plateau at the transition point between aerobic and anaerobic metabolism (LA) [27,50,51] . This point in resistance exercise occurs around 30% of maximum voluntary contraction [27,49,51] , suggesting that from this charge, hypoxia caused by muscle contraction stimulates glycolysis and accelerates the increase in lactate production.…”

“…This point in resistance exercise occurs around 30% of maximum voluntary contraction [27,49,51] , suggesting that from this charge, hypoxia caused by muscle contraction stimulates glycolysis and accelerates the increase in lactate production. From the anaerobic threshold then there is a reduction of the pH in muscles that stimulates metabolic receptors, causing increased sympathetic activity on the cardiovascular system, raising the HR.…”