Noninvasive method to estimate anaerobic threshold in individuals with type 2 diabetes

Abstract

BackgroundWhile several studies have identified the anaerobic threshold (AT) through the responses of blood lactate, ventilation and blood glucose others have suggested the response of the heart rate variability (HRV) as a method to identify the AT in young healthy individuals. However, the validity of HRV in estimating the lactate threshold (LT) and ventilatory threshold (VT) for individuals with type 2 diabetes (T2D) has not been investigated yet.AimTo analyze the possibility of identifying the heart rate variability threshold (HRVT) by considering the responses of parasympathetic indicators during incremental exercise test in type 2 diabetics subjects (T2D) and non diabetics individuals (ND).MethodsNine T2D (55.6 ± 5.7 years, 83.4 ± 26.6 kg, 30.9 ± 5.2 kg.m2(-1)) and ten ND (50.8 ± 5.1 years, 76.2 ± 14.3 kg, 26.5 ± 3.8 kg.m2(-1)) underwent to an incremental exercise test (IT) on a cycle ergometer. Heart rate (HR), rate of perceived exertion (RPE), blood lactate and expired gas concentrations were measured at the end of each stage. HRVT was identified through the responses of root mean square successive difference between adjacent R-R intervals (RMSSD) and standard deviation of instantaneous beat-to-beat R-R interval variability (SD1) by considering the last 60 s of each incremental stage, and were known as HRVT by RMSSD and SD1 (HRVT-RMSSD and HRVT-SD1), respectively.ResultsNo differences were observed within groups for the exercise intensities corresponding to LT, VT, HRVT-RMSSD and HHVT-SD1. Furthermore, a strong relationship were verified among the studied parameters both for T2D (r = 0.68 to 0.87) and ND (r = 0.91 to 0.98) and the Bland & Altman technique confirmed the agreement among them.ConclusionThe HRVT identification by the proposed autonomic indicators (SD1 and RMSSD) were demonstrated to be valid to estimate the LT and VT for both T2D and ND.

Reliability of heart rate variability threshold and parasympathetic reactivation after a submaximal exercise test

“…An increasing amount of evidence shows that the HRVT point coincides with the ventilatory and lactate threshold 4,11,12,13 , which are considered simple and practical measures for estimating the aerobic/anaerobic transition. Therefore, our results suggest that, beyond being a valid indicator of parasympathetic withdrawal, HRVT is a reproducible measure in a submaximal exercise test.…”

“…The point where the values in these two parasympathetic indices are stabilized is called the heart rate variability threshold (HRVT) and is considered an indicator of parasympathetic deactivation during an incremental exercise test 6,7,11 . Recent publications demonstrated that HRVT coincided with the first ventilatory threshold and lactate threshold, suggesting that HRVT might be a practical and attractive alternative to identify adequate workload for exercise prescription 4,12,13 . Conversely, analysis of vagal activity immediately post-exercise has been considered a complementary alternative for monitoring training status and control of internal load 14,15,16 .…”

Effects of continuous and intermittent endurance exercise in autonomic balance, rating perceived exertion and blood lactate levels in healthy subjects

“…16 The peak treadmill velocity (PTV) is defined as the final velocity reached and maintained for one minute for a maximum incremental test, which is associated with VO 2 max 17 and significantly correlated with the Maximal Aerobic Speed (vVO 2 max) (r = 0.90). 18 Determination of Lactate Threshold (LT) was conducted through the HRV and following the criteria used by Sales et al 19 Briefly, during low to moderate exercise intensity the heart rate increase is mainly controlled by the parasympathetic nervous system (PNS) withdrawal, but at higher intensities there is a reduction in HRR, heart rate reserve.…”

Increased lactate threshold after five weeks of treadmill aerobic training in rats

“…The maximal oxygen consumption (VO 2max ) and anaerobic threshold (AT) are parameters that have been widely considered as hallmarks of aerobic fitness for athletes (Svedahl and MacIntosh, 2003), physically active individuals (Simões et al, 2003) and, to a minor scale, for special populations (Belli et al, 2007;Motta et al, 2010;Sales et al, 2011). AT can be used in specific aerobic evaluations and is considered a gold standard parameter for exercise prescription, including cardiovascular risks groups (Belli et al, 2007;Farsidfar et al, 2008).…”