high-intensity interval training

Objective To explore the association between single nucleotide polymorphisms (SNPs) of the potassium voltage-gated channel subfamily C member 1 ( KCNC1 ) gene and the improvement of aerobic capacity after high-intensity interval training (HIIT), and to screen potential genetic markers sensitive to HIIT. Methods A total of 249 Han college students (115 males and 134 females, aged 21.00 ± 0.07 years) were recruited and underwent 12 weeks of HIIT intervention, three times a week. Aerobic capacity indicators were measured before and after the intervention. Genotyping was performed using the Infinium CGA gene chip, and five KCNC1 gene SNPs were obtained after quality control with PLINK software. Linear regression models were used to analyze the association between SNPs and the training change values (Δ) of each indicator, with gender, age, height and baseline values as covariates. Results After 12 weeks of HIIT, VO 2 max/kg, VCO 2 , and VE significantly increased ( P < 0.01). Submaximal heart rate during running economy (RE) assessment decreased significantly ( P < 0.01), whereas maximal heart rate did not change significantly ( P = 0.124). Association analysis revealed that three SNPs were significantly associated with training sensitivity: rs12574348 was suggestively associated with the Δ values of VO 2 max/kg ( β = -0.9319, P = 0.048) and submaximal HR (RE, β = 3.069, P = 0.020), with CC-type subjects showing the greatest increase in VO 2 max/kg and the greatest decrease in submaximal HR (RE); rs757511 was suggestively significantly associated with the Δ values of VCO 2 ( β = 0.1076, P = 0.014) and maximal HR ( β = 1.827, P = 0.048), with AA-type subjects showing the greatest increase in VCO 2 and GG-type subjects showing the greatest decrease in HR_max; rs61882396 was suggestively significantly associated with the Δ value of VO 2 /kg (RE, β = -0.7673, P = 0.020), with AA-type subjects showing the greatest decrease in VO 2 /kg (RE). None of the above SNPs were significantly associated with baseline indicators ( P > 0.05). Conclusion The polymorphisms of KCNC1 gene rs12574348, rs757511, and rs61882396 are suggestively significantly associated with the improvement of aerobic capacity indicators after HIIT, and the effects are independent of baseline levels, suggesting potential involvement of KCNC1 in training-related neuromuscular adaptations, although the exact mechanisms remain to be established, thereby influencing individual sensitivity to HIIT. This gene may serve as a potential genetic marker for predicting the training effect of HIIT.

matched text: “high intensity interval training”

Purpose Beetroot juice (BJ), a natural source of dietary nitrate, has been widely studied for its potential ergogenic effects; however, evidence integrating both aerobic and anaerobic performance outcomes remains limited. This meta-analysis evaluated the effects of BJ supplementation on maximal oxygen uptake (VO₂max), high-intensity interval sprint (HIS) performance, and mean power output (MPO). Methods A comprehensive literature search was conducted across six databases (Wiley Online Library, Web of Science, Scopus, SpringerLink, PubMed, and ScienceDirect), supplemented by manual searches of Google Scholar. Meta-analysis, subgroup analysis, meta-regression analysis, publication bias assessment, and sensitivity analyses were performed using Stata 17. Results Thirty-three studies were included in the review. BJ supplementation significantly improved HIS (SMD = 0.38, 95% CI 0.17 to 0.59, p < 0.001), MPO (SMD = 0.43, 95% CI 0.21 to 0.64, p < 0.001), and VO₂max (SMD = 0.30, 95% CI 0.05 to 0.55, p < 0.001). Heterogeneity was low across all outcomes (HIS: I 2 = 11.0%, p = 0.343; MPO: I 2 = 0.0%, p = 0.824; VO₂max: I 2 = 0.0%, p = 0.970). In addition, although subgroup difference tests did not show statistically significant differences, the observed data suggest that athlete status, sport type, supplementation strategy, juice brand, and timing of intake may act as potential effect modifiers. These findings should be interpreted as hypothesis-generating and require confirmation in future studies. Conclusion As a natural ergogenic aid, beetroot juice effectively improves both aerobic and anaerobic exercise performance and can be recommended. Systematic review registration Identifier CRD42025636836.

matched text: “high intensity interval”