Influence of "priming" exercise on oxygen uptake and muscle deoxygenation kinetics during heavy-intensity cycle exercise in type 2 diabetes

Joel Rocha, N. Gildea, D. O'Shea, S. Green, M. Egana

Research output: Contribution to conferenceAbstractpeer-review

Abstract

We tested the hypothesis that priming exercise (PE) would increase the speed of the adjustment of the primary phase (taup, tp) ofpulmonary oxygen uptake (VO2) and/or reduce the amplitude of the slow component of VO2 during high-intensity cycling in type 2diabetes (T2D) given that muscle oxygen supply appears to be limited in T2D. Ten middle-aged participants with uncomplicated T2D(49.6 ± 7.2 years, 30.8 ± 5.0 kg.m2; 8 men / 2 women) and 10 non-diabetic (ND) controls (44.6 ± 9.2 years, 30.8 ± 4.2 kg.m2; 8 men /2 women) were recruited. Participants completed four bouts of constant-load cycling corresponding to 50% between their ventilatorythreshold and VO2 peak power outputs, (i.e. 50%delta) previously established during a ramp incremental test. Two of these boutswere completed without priming exercise and two bouts were undertaken with prior heavy-intensity (50%delta) priming exercise. VO2kinetics was calculated from continuously measured breath-by-breath data, while the rate of muscle deoxygenation (i.e.,deoxygenated hemoglobin, HHb) was continuously measured by near–infrared spectroscopy (NIRS) at the vastus lateralis muscle. Atbaseline the time constant of the primary phase, tp, was approximately 17% slower (P>0.05) in T2D, and PE tended to reduce tp (P =0.06) in both groups by a similar magnitude (T2D, 37.9±17.7 vs. 33.7±10.6 s; ND, 31.0±5.8 vs. 28.0±6.3 s). The amplitude of the slowcomponent (As) was overall significantly lower (P<0.05) in T2D; and PE tended to overall reduce it (P=0.09). These reductions wereof approximately 50% in T2D and only 5% in ND controls (T2D, 0.29±0.13 vs 0.18±0.10 L.min-1; ND, 0.39±0.18 vs 0.37±0.21L.min-1), however, there was no significant interaction between diabetes status and priming bout in As (P = 0.22). The rate ofadjustment or amplitude of deoxygenated heamoglobin (HHb) did not show any differences between groups. These preliminary datasuggest that in middle-aged adults with T2D, priming exercise prior to heavy-intensity exercise can potentially speed the primaryphase VO2 kinetics and reduce the amplitude of the slow component possibly due to an improvement in oxygen delivery.Nevertheless interindividual variability in responses precluded the attainment of statistical significance. 
Original languageEnglish
Publication statusPublished - 1 Jul 2016
Event21st annual Congress of the European College of Sport Science: Crossing Borders through Sport Science - Austria Center Vienna (ACV), Vienna, Austria
Duration: 6 Jul 20169 Jul 2016
Conference number: 21
https://sport-science.org/index.php/congress/where-we-meet

Conference

Conference21st annual Congress of the European College of Sport Science
Country/TerritoryAustria
CityVienna
Period6/07/169/07/16
Internet address

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