Peripheral Blood Flow Responses to Electromagnetic Energy

Inclusion Criteria:

* Participants will be healthy subjects over the age of 18.
* Men and women will be recruited for participation.
* All ethnicities will be included in this study.

Exclusion Criteria:

Exclusionary criteria include:

* age under 18 years and those over 60 years of age,
* those who are unable to understand the consent process,
* those who cannot read or speak English,
* a history of cancer,
* peripheral artery disease,
* diabetes mellitus,
* active pregnancy,
* hypersensitivity to perflutren contrast agents,
* pulmonary hypertension,
* chronic kidney disease,
* active tobacco or drug use,
* blood pressure over 160/90, BMI\>30,
* sickle cell disease, or
* history of intracardiac shunt.

Additional exclusion criteria include:

* a history of coronary artery disease,
* heart failure,
* the presence of an implanted defibrillator or pacemaker,
* a history of heart murmur or rhythm disorder (atrial fibrillation, atrial tachycardia, or ventricular tachycardia),
* neurological diseases such as stroke, and
* any uncontrolled medical conditions.