Does voluntary hypoventilation during exercise impact EMG activity?

Abstract

It has been reported that exercise under hypoxic conditions induces reduced muscle oxygenation, which could be related to enhanced activity on electromyography (EMG). Although it has been demonstrated that exercise under conditions of voluntary hypoventilation (VH) evokes muscle deoxygenation, it is unclear whether VH during exercise impacts EMG. Seven men performed bicycle exercise for 5 min at 65 % of peak oxygen uptake with normal breathing (NB) and VH. Muscle oxygenation; concentration changes in oxyhemoglobin (Oxy-Hb), deoxyhemoglobin (Deoxy-Hb) and total hemoglobin (Total-Hb); and surface EMG in the vastus lateralis muscle were simultaneously measured. In the VH condition, Oxy-Hb was significantly lower and Deoxy-Hb was significantly higher compared to those in the NB condition (P < 0.05 for both), whereas there was no significant difference in Total-Hb between the two conditions. We observed significantly higher values (P < 0.05) on integrated EMG during exercise under VH conditions compared to those under NB conditions. This study suggests that VH during exercise augments EMG activity.

The Effect of Breathing Patterns Common to Competitive Swimming on Gas Exchange and Muscle Deoxygenation During Heavy-Intensity Fartlek Exercise

“…The data in this study show that the aerobic metabolic demand (i.e., VO 2 ) was supported by the decreased S at O 2 ( Table 3 and Figure 3C ) and increased muscle deoxygenation under the reduced perfusion conditions, as reflected by the much greater decrease in mean Δ[Hb tot ] ( Table 3 and Figure 3D ) and modest decrease in Δ[HHb] ( Table 3 and Figure 3A ). A similar reduction in S at O 2 and an increase in muscle deoxygenation were observed by Kume et al (2016) at a PO corresponding to 65% of VO 2max interspersed with 4 s exhalations followed by a maximal inhalation, simulating hypoventilation. Furthermore, previous work by Hoffmann et al (2005) under apneic and rebreathing exercise conditions during higher intensity exercise, which generated similar hypoxia (decreased P ET O 2 in rebreathing), demonstrated greater mean arterial pressure and lower heart rate in the apneic compared to the rebreathing condition, demonstrating that only the apneic state elicited the observed O 2 conservation or diving response that is associated with the decreased intramuscular blood flow.…”

Application of Molecular Hydrogen as an Antioxidant in Responses to Ventilatory and Ergogenic Adjustments during Incremental Exercise in Humans

“…As shown in Figure 4 , the greater deoxy[Hb + Mb] concentrations as a function of ventilation in the HCP subjects might be attributed to increased oxygen extraction at hypoventilation that accompanies the greater recruitment of fast-twitch fibers [ 47 ]. In addition, the S t O 2 value in the RF muscle was lower with HCP compared to the placebo as a result of hypoventilation.…”

Breath Tools: A Synthesis of Evidence-Based Breathing Strategies to Enhance Human Running

“…The various effects of hypoxia and hypercapnia have been rigorously studied ( Millet et al, 2016 ; Girard et al, 2020 ), and BH is an accessible method for runners to replicate such benefits. In short, BH is a strong metabolic stressor similar to hypoxic training that causes accelerated muscle deoxygenation, hypercapnia, and increased muscle activity during exercise ( Kume et al, 2016 ; Toubekis et al, 2017 ). BH protocols lasting 3–5 weeks reported performance gains of 3%–4% related to two acute mechanisms: increased stroke volume (up to 30%) and haemoglobin concentration (up to 10%; Woorons et al, 2016 ; Lapointe et al, 2020 ; Woorons et al, 2020 ).…”