Impact of exercise in high-humidity on heart rate variability and salivary oxidative stress in obese and lightweight asthmatic children

Abstract

Background: Asthma and obesity are becoming increasingly common among children. Such conditions are known to negatively affect both cardiac autonomic function and oxidative stress. We therefore investigated the heart rate variability (HRV) and oxidative (malondialdehyde, MDA) response to exercise within a high humidity environment (~65%) in obese and lightweight asthmatic children.Methods: Forty-two children participated in this study and were categorized into four groups: obese asthmatic (OA, n = 10), obese non-asthmatic (ONA, n = 15), lightweight asthmatic (LA, n = 10), and lightweight non-asthmatic (LNA, n = 7). Time-domain and nonlinear indices of HRV were assessed at rest, during, and immediately after exercise. Further, saliva samples were collected immediately before and after exercise and analysed for the determination of MDA.Results: HRV significantly decreased during and after exercise compared to baseline (P < 0.05) with short-term fractal scaling exponent (α1) for the LNA group significantly smaller than the OA group after exercise (P < 0.05). In contrast, the long-term fractal scaling exponent (α2) was greater after exercise compared to baseline and during exercise for all groups (P<0.05). MDA significantly decreased after exercise compared to baseline (P<0.05).We also found significant correlations after exercise between salivary levels of MDA with HRV components (i.e., RMSSD, SD1, and α2) in asthmatic groups (all P<0.05). Conclusions:Our findings showed that exercise in high humidity environment does not significantly differentiate the autonomic response among children with various conditions (i.e., obese, asthmatic and healthy). However, a significant relationship was found between HRV and MDA in asthmatic children after exercise, highlighting the inter-relationship between oxidative stress markers and autonomic function in asthmatic children.

Impact of asthma on heart rate variability in children and adolescents: Systematic review and meta‐analysis

“…In addition, 2 of the 4 studies found 5,12 demonstrated lower SDNN values in the asthma group. Regarding RMSSD, 5 of 6 studies 3,6,12,14,25 found higher values in the asthma group; only Rimes et al 26 found a lower value in the asthma group. As for frequency‐domain variables, 6 of 8 studies 4,12,15,25,28,29 found higher HF values in the asthma group; only Kazuma et al 5 and Rimes et al 26 found lower values in the asthma group.…”

“…Ten studies 3,4,6,14–16,24–26,28 assessed HRV using short‐term recordings (ranging from 10 s to 10 min), and 4 5,12,13,29 used long‐term measurements (24 h). Regarding HRV software, 4 studies 4,14,16,24 used Kubios HRV. The main HRV variables included R‐R, SDNN, RMSSD, pNN50, LF, HF, LF/HF, SD1 and SD2 (Table 2).…”

“…All studies were published between 1985 and 2020 (Table 1). Ten studies 3,4,6,[14][15][16][24][25][26]28 assessed HRV using shortterm recordings (ranging from 10 s to 10 min), and 4 Franco et al 4 Polar RS800CX 5 min Kubios HRV HF, LF, LF/HF Note: R-R: mean of R-R intervals; HF: high frequency; LF: low frequency; LF/HF: ratio of LF-to-HF power; NNA: mean of normal-to-normal R-R intervals over 24 h; SDRR: standard deviation of all normal R-R intervals over 24 h; SDANN: standard deviation of the average NN intervals for each 5 min segment of a 24 h recording; SD: mean of standard deviation of all normal R-R intervals for all 5-min periods over 24 h; %RR50: percentage difference between adjacent normal R-R intervals that were greater than 50 ms, computed over the entire 24 h AECG; SDNN: standard deviation of all normal sinus R-R intervals; RMSSD: root mean square of successive differences between normal sinus R-R intervals; PNN50: percentage of successive R-R intervals that differ by more than 50 ms; SNN50: number of R-R intervals exceeding 50 ms; HRV-Triangular Index: integral of the density of the R-R interval histogram divided by its height; HF bf : expanded high frequency power (0.15-Bf Hz); TP: total power; TP bf : total expanded power; LF:HF bf : low and expanded high frequency powers as a ratio; SD1: poincare plot standard deviation perpendicular to the line of identity; SD2: poincare plot standard deviation along the line of identity; DFA: detrended fluctuation analysis, which describes short-term fluctuations (α1) and long-term (α2); AECG: ambulatory electrocardiograph; ECG: electrocardiogram; CAFTS: software package; SCM280: computer-based system; SCM: computer-based system.…”

“…14,16,24 were classified as high quality and 10 3,6,12,13,15,25-29 as T A B L E 3 (Continued) Values expressed as mean ± standard deviation.Abbreviations: A, asthma; C, control; HF, high frequency; LF, low frequency; LF/HF, ratio of LF-to-HF power; nu, normalized units; PNN50, percentage of successive R-R intervals that differ by more than 50 ms; RMSSD, root mean square of successive differences between normal sinus R-R intervals; SD1, poincare plot standard deviation perpendicular to the line of identity; SD2, poincare plot standard deviation along the line of identity; SDNN, standard deviation of all normal sinus R-R intervals.a Coefficient of variation. b No standard deviation provided.…”

Exercise Outcomes in Childhood Obesity-Related Inflammation and Oxidative Status

“…Although there is limited research investigating the impact of physical activity interventions on childhood obesity-associated oxidative stress ( Table 1.2B ), acute aerobic cycling exercise seems to exert contrary effects on oxidative markers in obese children. Specifically, Ahmadian et al ( 70 ) reported a decrease in MDA levels after an acute progressive test until volitional exhaustion in both obese and normal-weight children under the age of 13 years, as well as in their asthmatic counterparts ( 70 ), Paltoglou et al ( 71 ) reported an increase in the levels of TBARS and protein carbonyls (PCs), as well as in TAC, and catalase, along with a decrease in the production of GSH and GSH/GSSG in both prepubertal and pubertal obese children following an acute bout of maximal aerobic exercise. These responses to acute aerobic exercise were also observed in their prepubertal and pubertal normal-weight counterparts.…”