Impact of ventilatory threshold on myocardial work during sub-maximal exercise
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Purpose: The primary purpose of this investigation was to identify how myocardial work responds at different ventilatory threshold (VT) points. Method: Subjects completed a standardised incremental exercise test to voluntary fatigue ( ̇O2 max) in order to identify their point of VT. 18 healthy male subjects from a range of exercise modalities volunteered to participate in the investigation. Following determination of VT, individuals were then exercised at 40% of their ̇O2 peak to identify whether different ventilatory thresholds influence myocardial work during sub-maximal exercise. Results: Results revealed that myocardial work (RPP) was shown to be significantly higher in the low VT group compared to the high VT group, (p<0.01). Additionally, HR was significantly higher in individuals with a low VT (p<0.05), despite V O2 mean, systolic and diastolic BP, HRR, ̇O2 reserve, cardiac output, cardiac index, stroke volume, and stroke volume index not being significant (p>0.05), despite exercising at the same relative exercise intensity. There was no difference in V O2 peak between the low and high VT group (p=0.9821). VT was however found to be significantly different between both groups (p<0.0001) demonstrating that VT was not directly related to V O2 peak (p>0.05). Conclusion: Despite similar ̇O2, ̇O2 reserve, ̇E, HRR, %HRR, and similar cardiac output when exercising at the same relative exercise intensity, myocardial work was higher during sub-maximal exercise in humans with a low VT.
- Masters Degrees (Sport) 
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