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Exercise intensity modulates brachial artery retrograde blood flow and shear rate during leg cycling in hypoxia.

Iwamoto E, Katayama K, Ishida K - Physiol Rep (2015)

Bottom Line: The subjects performed two maximal exercise tests on a semi-recumbent cycle ergometer to estimate peak oxygen uptake (V˙O2peak) while breathing normoxic (inspired oxygen fraction [FIO2 = 0.21]) and hypoxic (FIO2 = 0.12 or 0.13) gas mixtures.Brachial artery diameter and blood velocity were simultaneously recorded, using Doppler ultrasonography.In contrast, retrograde blood flow and SR in hypoxia remained significantly elevated above baseline and was significantly greater at 60% than at 30% V˙O2peak.

View Article: PubMed Central - PubMed

Affiliation: School of Health Sciences, Sapporo Medical University, Sapporo, Japan e.iwamoto@sapmed.ac.jp.

No MeSH data available.


Related in: MedlinePlus

Cardiorespiratory variables at rest and during exercise under normoxic and hypoxic conditions. (A) HR, (B) SBP, and (C) DBP. Values expressed as mean ± SE. SBP, systolic blood pressure; DBP, diastolic blood pressure; HR, heart rate; Norm 30, 30% O2peak in normoxia; Norm 60, 60% O2peak in normoxia; Hypo 30, 30% O2peak in hypoxia; Hypo 60, 60% O2peak in hypoxia. *P < 0.05 Norm 30 versus Norm 60, §P < 0.05 Hypo 30 versus Hypo 60, †P < 0.05 Norm 30 versus Hypo 30, ‡P < 0.05 Norm 60 versus Hypo 60, a: P < 0.05 versus Rest 1 in Norm 30, b: P < 0.05 versus Rest 1 in Norm 60, c: P < 0.05 versus Rest 1 in Hypo 30, d: P < 0.05 versus Rest 1 in Hypo 60.
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fig02: Cardiorespiratory variables at rest and during exercise under normoxic and hypoxic conditions. (A) HR, (B) SBP, and (C) DBP. Values expressed as mean ± SE. SBP, systolic blood pressure; DBP, diastolic blood pressure; HR, heart rate; Norm 30, 30% O2peak in normoxia; Norm 60, 60% O2peak in normoxia; Hypo 30, 30% O2peak in hypoxia; Hypo 60, 60% O2peak in hypoxia. *P < 0.05 Norm 30 versus Norm 60, §P < 0.05 Hypo 30 versus Hypo 60, †P < 0.05 Norm 30 versus Hypo 30, ‡P < 0.05 Norm 60 versus Hypo 60, a: P < 0.05 versus Rest 1 in Norm 30, b: P < 0.05 versus Rest 1 in Norm 60, c: P < 0.05 versus Rest 1 in Hypo 30, d: P < 0.05 versus Rest 1 in Hypo 60.

Mentions: Respiratory and cardiovascular variables are shown in Tables2, 3 and Fig. 2. Three-way interaction (intensity × FIO2 × time) was significant for HR but not for SpO2, SBP, and DBP. For HR, there were significant simple interactions, for intensity × FIO2 at 30 min, and for intensity × time under both exercise intensities. For BP, main effects of intensity and time on SBP and DBP were significant, but no other main effects were observed. SBP at 60% O2peak was significantly higher than at 30% O2peak under both oxygen conditions, but no significant differences were observed between normoxia and hypoxia. There were no significant differences in DBP between 30 and 60% O2peak under normoxic and hypoxic conditions. DBP in normoxia was unchanged from resting levels except at 30 min of exercise at 30% O2peak. In contrast, DBP in hypoxic trials showed significant decreases from baseline values as exercise progressed, and DBPs at 30 min in hypoxia at both exercise intensities were lower than those in normoxia. For SpO2, there was a significant interaction effect (FIO2 × time), and significant main effects of FIO2 and time. Hypoxia decreased SpO2 at both exercise intensities. RPE at 30 min of exercise at 30% O2peak was significantly lower than at 60% O2peak under normoxic and hypoxic conditions (30% O2peak vs. 60% O2peak, normoxia; 10.3 ± 0.5 vs. 15.9 ± 0.4. Hypoxia; 9.9 ± 0.9 vs. 15.0 ± 0.3).


Exercise intensity modulates brachial artery retrograde blood flow and shear rate during leg cycling in hypoxia.

Iwamoto E, Katayama K, Ishida K - Physiol Rep (2015)

Cardiorespiratory variables at rest and during exercise under normoxic and hypoxic conditions. (A) HR, (B) SBP, and (C) DBP. Values expressed as mean ± SE. SBP, systolic blood pressure; DBP, diastolic blood pressure; HR, heart rate; Norm 30, 30% O2peak in normoxia; Norm 60, 60% O2peak in normoxia; Hypo 30, 30% O2peak in hypoxia; Hypo 60, 60% O2peak in hypoxia. *P < 0.05 Norm 30 versus Norm 60, §P < 0.05 Hypo 30 versus Hypo 60, †P < 0.05 Norm 30 versus Hypo 30, ‡P < 0.05 Norm 60 versus Hypo 60, a: P < 0.05 versus Rest 1 in Norm 30, b: P < 0.05 versus Rest 1 in Norm 60, c: P < 0.05 versus Rest 1 in Hypo 30, d: P < 0.05 versus Rest 1 in Hypo 60.
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fig02: Cardiorespiratory variables at rest and during exercise under normoxic and hypoxic conditions. (A) HR, (B) SBP, and (C) DBP. Values expressed as mean ± SE. SBP, systolic blood pressure; DBP, diastolic blood pressure; HR, heart rate; Norm 30, 30% O2peak in normoxia; Norm 60, 60% O2peak in normoxia; Hypo 30, 30% O2peak in hypoxia; Hypo 60, 60% O2peak in hypoxia. *P < 0.05 Norm 30 versus Norm 60, §P < 0.05 Hypo 30 versus Hypo 60, †P < 0.05 Norm 30 versus Hypo 30, ‡P < 0.05 Norm 60 versus Hypo 60, a: P < 0.05 versus Rest 1 in Norm 30, b: P < 0.05 versus Rest 1 in Norm 60, c: P < 0.05 versus Rest 1 in Hypo 30, d: P < 0.05 versus Rest 1 in Hypo 60.
Mentions: Respiratory and cardiovascular variables are shown in Tables2, 3 and Fig. 2. Three-way interaction (intensity × FIO2 × time) was significant for HR but not for SpO2, SBP, and DBP. For HR, there were significant simple interactions, for intensity × FIO2 at 30 min, and for intensity × time under both exercise intensities. For BP, main effects of intensity and time on SBP and DBP were significant, but no other main effects were observed. SBP at 60% O2peak was significantly higher than at 30% O2peak under both oxygen conditions, but no significant differences were observed between normoxia and hypoxia. There were no significant differences in DBP between 30 and 60% O2peak under normoxic and hypoxic conditions. DBP in normoxia was unchanged from resting levels except at 30 min of exercise at 30% O2peak. In contrast, DBP in hypoxic trials showed significant decreases from baseline values as exercise progressed, and DBPs at 30 min in hypoxia at both exercise intensities were lower than those in normoxia. For SpO2, there was a significant interaction effect (FIO2 × time), and significant main effects of FIO2 and time. Hypoxia decreased SpO2 at both exercise intensities. RPE at 30 min of exercise at 30% O2peak was significantly lower than at 60% O2peak under normoxic and hypoxic conditions (30% O2peak vs. 60% O2peak, normoxia; 10.3 ± 0.5 vs. 15.9 ± 0.4. Hypoxia; 9.9 ± 0.9 vs. 15.0 ± 0.3).

Bottom Line: The subjects performed two maximal exercise tests on a semi-recumbent cycle ergometer to estimate peak oxygen uptake (V˙O2peak) while breathing normoxic (inspired oxygen fraction [FIO2 = 0.21]) and hypoxic (FIO2 = 0.12 or 0.13) gas mixtures.Brachial artery diameter and blood velocity were simultaneously recorded, using Doppler ultrasonography.In contrast, retrograde blood flow and SR in hypoxia remained significantly elevated above baseline and was significantly greater at 60% than at 30% V˙O2peak.

View Article: PubMed Central - PubMed

Affiliation: School of Health Sciences, Sapporo Medical University, Sapporo, Japan e.iwamoto@sapmed.ac.jp.

No MeSH data available.


Related in: MedlinePlus