Description:
A limited number of studies suggest an association between body mass index (BMI) and neural cardiovascular reactivity to mental stress in humans, but this relationship has not been comprehensively examined. We tested the hypothesis that overweight subjects (BMI ≥ 25 kg/m2) would demonstrate augmented neural and cardiovascular responses to mental stress when compared to normal weight individuals. Retrospective analysis of studies with recordings of heart rate (HR), mean arterial pressure (MAP), and muscle sympathetic nerve activity (MSNA) during 5 min of mental stress (via mental arithmetic) yielded 60 normal weight (age 23±1 yr; BMI 22±0 kg/m2) and 61 overweight (age 24±1 yr; BMI 28±0 kg/m2) subjects. Resting HR and MSNA were similar between normal and overweight subjects, while resting MAP was higher in overweight subjects (77±1 vs. 84±1 mmHg; P<0.05). MAP (Δ11±1 vs. Δ13±1 mmHg), HR (Δ18±1 vs. Δ18±1 beats/min), and MSNA (Δ4±1 vs. Δ5±1 bursts/min) responses to mental stress were similar between normal and overweight participants, respectively. In conclusion, our findings indicate that being classified as ‘overweight’ according to BMI standards does not increase neural or cardiovascular reactivity to mental stress. However, it remains unclear if more specific classifications of obesity (i.e., fat composition and distribution) influence neural cardiovascular reactivity to mental stress. Supported by NIH.