Overweight and sympathetic overactivity in black Americans

Area of Science:

• Cardiovascular Physiology
• Neuroscience
• Health Disparities

Background:

• The sympathetic nervous system plays a key role in linking obesity and hypertension.
• Existing research primarily involves white populations, limiting generalizability.
• Black Americans face a disproportionately high risk of hypertension.

Purpose of the Study:

• To investigate the relationship between overweight and sympathetic overactivity in Black Americans.
• To determine if body mass influences sympathetic nerve activity differently across racial groups.

Main Methods:

• Microneurography was used to record postganglionic sympathetic nerve discharge.
• Measurements were taken from the peroneal nerve in normotensive Black and White men and women.
• Body mass index (BMI) was assessed across a wide range.

Main Results:

• Overweight Black women exhibited a significant positive correlation between BMI and sympathetic nerve activity (r=0.45, P=0.0009).
• In Black men, sympathetic nerve discharge was not correlated with BMI (r=0.03, P=NS).
• Lean Black men displayed significantly higher sympathetic nerve discharge than lean White men and lean/overweight Black and White women (28±3 vs. 17–21 bursts/min; P<0.05).

Conclusions:

• This study provides the first microneurographic evidence of tonic central sympathetic overactivity in Black individuals.
• Adiposity is linked to sympathetic overactivity in Black women.
• Adiposity-independent sympathetic overactivity is present in Black men, suggesting a unique racial predisposition to hypertension.