Physiological responses to interval endurance exercise at different levels of blood flow restriction.
OBJECTIVE
We aimed to identify a blood flow restriction (BFR) endurance exercise protocol that would both maximize cardiopulmonary and metabolic strain, and minimize the perception of effort.


METHODS
Twelve healthy males (23 ± 2 years, 75 ± 7 kg) performed five different exercise protocols in randomized order: HI, high-intensity exercise starting at 105% of the incremental peak power (Ppeak); I-BFR30, intermittent BFR at 30% Ppeak; C-BFR30, continuous BFR at 30% Ppeak; CON30, control exercise without BFR at 30% Ppeak; I-BFR0, intermittent BFR during unloaded exercise. Cardiopulmonary, gastrocnemius oxygenation (StO2), capillary lactate ([La]), and perceived exertion (RPE) were measured.


RESULTS
V̇O2, ventilation (V̇E), heart rate (HR), [La] and RPE were greater in HI than all other protocols. However, muscle StO2was not different between HI (set1-57.8 ± 5.8; set2-58.1 ± 7.2%) and I-BRF30 (set1-59.4 ± 4.1; set2-60.5 ± 6.6%, p < 0.05). While physiologic responses were mostly similar between I-BFR30 and C-BFR30, [La] was greater in I-BFR30 (4.2 ± 1.1 vs. 2.6 ± 1.1 mmol L-1, p = 0.014) and RPE was less (5.6 ± 2.1 and 7.4 ± 2.6; p = 0.014). I-BFR30 showed similar reduced muscle StO2compared with HI, and increased blood lactate compared to C-BFR30 exercise.


CONCLUSIONS
Therefore, this study demonstrate that endurance cycling with intermittent BFR promotes muscle deoxygenation and metabolic strain, which may translate into increased endurance training adaptations while minimizing power output and RPE.
Human Performance Research Group, Center for Health and Exercise Science, UDESC, Florianopolis, Brazil. bulhoes_ef@yahoo.com.br.|Division of Pulmonary and Critical Care Physiology and Medicine, Rehabilitation Clinical Trials Center, Los Angeles Biomedical Research Center at Harbor-UCLA Medical Center, Torrance, CA, USA. bulhoes_ef@yahoo.com.br.
Rogério B
http://orcid.org/0000-0002-4880-4935
RB
Corvino
Division of Pulmonary and Critical Care Physiology and Medicine, Rehabilitation Clinical Trials Center, Los Angeles Biomedical Research Center at Harbor-UCLA Medical Center, Torrance, CA, USA.|School of Biomedical Sciences, University of Leeds, Leeds, UK.
Harry B
HB
Rossiter
Human Performance Research Group, Center for Health and Exercise Science, UDESC, Florianopolis, Brazil.
Thiago
T
Loch
Human Performance Research Group, Center for Health and Exercise Science, UDESC, Florianopolis, Brazil.
Jéssica C
JC
Martins
Human Performance Research Group, Center for Health and Exercise Science, UDESC, Florianopolis, Brazil.
Fabrizio
F
Caputo
D000328:Adult; D003326:Coronary Circulation; D015444:Exercise; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply / Q000502:physiology; D010101:Oxygen Consumption; D010807:Physical Endurance; D011652:Pulmonary Circulation; D012039:Regional Blood Flow
Cycle ergometry; High-intensity exercise; Lactate; Near-infrared spectroscopy; O2 uptake; Rating of Perceived Exertion