Recent reports have raised concerns about the Halo's access to this extensive personal and private health information, the lawmaker wrote in the letter this week.
Amy Klobuchar, a Senator from Minnesota, has asked the department to ensure that users' health data is secure.
"Recent reports have raised concerns about the Halo's access to this extensive personal and private health information," the lawmaker wrote in the letter this week.
"Among publicly available consumer health devices, the Halo appears to collect an unprecedented level of personal information."
Last year, a study by BMJ (formerly the British Medical Journal) found that 79 per cent of health apps studied by researches were found to share user data in a manner that failed to provide transparency about the data being shared.
"The Halo enters the consumer market at a time where there are very few federal regulations in place to require privacy and security protections for consumer's personal health data collected by these wearable fitness devices," Klobuchar said in the letter.
Concerns over health data privacy became particularly relevant last year when Google bought Fitbit and data privacy experts cautioned that current laws and regulations do little to hold Google and other companies accountable to adhere to basic privacy standards.
"More must be done to ensure the privacy and security of health-related consumer devices," she said.
Amazon told TechCrunch in a statement that they have been in touch with Senator Klobuchar's office to address their questions about Amazon Halo.
"Privacy is foundational to how we designed and built Amazon Halo. Body and Tone are both optional features that are not required to use the product. Amazon does not have access to Body scan images or Tone speech samples," the spokesperson was quoted as saying.