Maria, Thank you for your question. Your health science background will absolutely be advantageous to you in your career. I would personally recommend mechanical engineering but both degrees will be highly valuable in the current job market. I believe that your science background can be applied to many areas that utilize mechanical engineering. For example, physiology and mechanical (or biomedical) engineering are fundamental to researching and designing medical devices (artificial knees, physical therapy equipment, etc.). Also, mechanical engineering is applicable to nearly everything. Most importantly, having any engineering degree signifies an applicant is disciplined in methodical, logical reasoning. You cant go wrong with either choice. Best of luck!