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Obesity and neural cardiovascular responses to mental stress in humans
Author(s) -
Wakeham Travis,
Harwood Morton,
Carter Jason,
Durocher John
Publication year - 2015
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.29.1_supplement.806.5
Subject(s) - body mass index , blood pressure , obesity , heart rate , medicine , sympathetic nervous system , mean arterial pressure , endocrinology , psychology , cardiology
The relationship between body mass index (BMI) and reactivity to mental stress remains inconclusive in humans. We tested the hypothesis that obese individuals (BMI > 30 kg/m 2 ) would demonstrate augmented neural and cardiovascular responses to mental stress when compared to normal weight (BMI < 25 kg/m 2 ) individuals. Heart rate (HR), mean arterial pressure (MAP), and muscle sympathetic nerve activity (MSNA) were simultaneously recorded during 5 min of mental stress (via mental arithmetic) in 26 normal weight (age 24±2 yr; BMI 22±0 kg/m 2 ) and 14 obese (age 29±2 yr; BMI 34±1 kg/m 2 ) participants. Resting MAP was higher (p<0.01) in obese (89±2 mmHg) vs. normal weight participants (77±1 mmHg), while resting HR and MSNA were similar between groups. Perceived stress (2.5±0.2 vs. 2.6±0.1 units) and HR (Δ17±2 vs. Δ18±2 beats/min) responses to mental stress were similar for the normal weight and obese, respectively. The MAP response to mental stress was augmented (p<0.05) in the obese (Δ15±2 mmHg) compared to normal weight (Δ11±1 mmHg). In contrast, the MSNA responses to mental stress were blunted (p<0.05) in the obese (Δ1±2 bursts/min) compared to normal weight (Δ5±1 bursts/min). In conclusion, obesity is associated with an augmented MAP reactivity to mental stress, but this augmentation was associated with a paradoxical reduction of MSNA reactivity. Future work might be aimed at replicating the augmented MAP reactivity in obese participants, and examining sympathetic vascular transduction and other potential mechanisms.