Endurance training improves post-exercise cardiac autonomic modulation in obese women with and without type 2 diabetes

Abstract

Obesity and type 2 diabetes (T2D) are associated with abnormal cardiovascular autonomic function and increased risk for cardiac complications, especially after exercise. Since improvements at rest are not always observed after training, we investigated changes in resting and post-exercise autonomic function in obese women with and without T2D after16-week of walking training. Heart rate (HR) variability (HRV) and baroreflex sensitivity (BRS) were measured at rest and 20 min after a 20 min bout of treadmill exercise at 65% VO(2) peak in obese women with (n = 8) and without T2D (n = 12) before and after training. HRV was analyzed by frequency-domain [high- (HF) power and low-frequency (LF)] and BRS by the sequence method. Exercise training induced similar significant changes in VO(2) peak, resting systolic blood pressure (SBP) and post-exercise autonomic function in both groups. Training increased VO(2 )peak (6%; P < 0.01) and decreased resting SBP (8%; P < 0.001). Increased post-exercise HR recovery (5%; P < 0.001), HF power (14%; P < 0.05), LF power (14%; P < 0.05) and BRS (86%; P < 0.001) were also observed. Resting autonomic function and post-exercise SBP were not altered after training. In conclusion, endurance training reduced blood pressure without changes in HRV and BRS at rest, but training increased HRV and BRS during the recovery of acute endurance exercise indicating an improved post-exercise autonomic modulation of HR, which was similar in obese women with and without T2D.

Effects of aerobic training intensity on resting, exercise and post-exercise blood pressure, heart rate and heart-rate variability

“…41,42 Cross-sectional data showed that endurancetrained participants exhibit a more rapid HR recovery than their untrained counterparts after exercise at similar relative work loads. 43,44 Concordant to some intervention studies, 13,45,19 but at variance with others, 17,18 we found HR recovery to be significantly faster after HI training, and to a lesser extent, also after LI training. Training did not affect post-exercise HRV, which is compatible with the observations of Perini et al, 18 Märtinmaki et al 17 and Verheyden et al, 19 who also did not find any change in post-exercise HRV after, respectively, 8 weeks, 14 weeks and 1 year of low to high-intensity endurance training.…”

“…11 Further, regular physical activity has been shown to lower resting HR; 12 to improve HR recovery after acute exercise 12,13 and to increase global HRV [14][15][16] in several studies, though not all. 15,[17][18][19] These equivocal results could be because of differences in training characteristics.…”

Effect of exercise on cardiac autonomic function in females with rheumatoid arthritis

“…Our results are confirmed by that of Jurca et al in 2004 who, after 8 weeks of moderate exercise training in females, showed improved vagal modulation of heart rate on 10-min resting ECGs [36]. Many previous studies done on diseased populations to evaluate the effect of short-term exercise intervention on short-term HRV modification assessed only supine variables [37][38][39][40][41][42][43]. Sandercock et al in 2007 observed significant increases in the supine RR interval, SDRR, LF(ln) and HF In the present study, only the RR interval increased significantly in the supine position, while the other variables did not show significant changes in favour of the exercise group.…”

“…Similar studies, e.g. on diabetic [43,45] and cardiac patients [38,40,41], had equal or even less participants. Heart rate variability was the only tool used to assess the function of the autonomic nervous system.…”

Early autonomic dysfunction in type 1 diabetes: a reversible disorder?

“…Notably, in heart failure and after myocardial infarction, interventions like physical training have generated rather strong evidence of a reversal of autonomic abnormalities [24,25]. Recent studies also seem to confirm that autonomic abnormalities can also be favourably influenced by physical exercise in patients with type 2 diabetes [47,48]. On the other hand, our findings are not in contrast with the development of progressive autonomic neuropathy at a later stage.…”