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Hypoxic exercise responses in lean and obese humans
Author(s) -
Limberg Jacqueline K,
Evans Trent,
Blain Gregory,
Zillner Caitlin,
Proctor Lester,
Sebranek Josh,
Schrage William
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.990.7
Subject(s) - forearm , medicine , endocrinology , hypoxia (environmental) , blood flow , skeletal muscle , vo2 max , physical exercise , lean body mass , cardiology , blood pressure , heart rate , chemistry , oxygen , anatomy , body weight , organic chemistry
No studies have tested whether obese humans exhibit reduced skeletal muscle blood flow during dynamic exercise under conditions of hypoxia. We hypothesized that exercise‐induced blood flow to skeletal muscle would be lower in young healthy obese subjects (BMI 38.5±2.0 kg/m 2 ) compared to lean subjects (BMI 23.3±0.6 kg/m 2 ). We measured forearm blood flow (FBF, using Doppler Ultrasound) and oxygen levels (pulse oximetry) during rest and steady‐state dynamic forearm exercise (20 contractions/min at ~20% maximal voluntary contraction) under two conditions: normoxia (0.21 F i O 2 , 98% S a O 2 ) or hypoxia (~0.10 F i O 2 , 80% S a O 2 ). Forearm blood flow relative to muscle mass (rFBF) during steady‐state normoxic exercise was similar between lean (n=18) and obese (n=14) subjects (p>0.05). Forearm exercise under conditions of hypoxia significantly increased rFBF from normoxic levels in lean (p<0.05) but not in obese subjects (p>0.05). Our results suggest that relative forearm blood flow is maintained during dynamic exercise under normoxic conditions in obese subjects. Under hypoxic conditions, lean controls further increase rFBF, whereas obese subjects do not. These results suggest under conditions of hypoxic stress obese, otherwise healthy, adults may not respond appropriately to hypoxia. Research Support: AFAR A08235, AHA 0815622G, NIH HL091397.