A 28-year-old “workout queen” who fueled her gym visits with caffeine supplements and energy drinks died of a heart attack — and her mother believes it’s because of the beverages.

Although the brand Donnell drank wasn’t identified, some energy drinks can contain up to 200 mg. of caffeine per can. Up to 400 mg. of caffeine a day is considered “safe,” the Mayo Clinic says.

Katie Donnell was a fitness enthusiast who also drank up to three energy drinks a day. Kennedy News and Media “At 28, you just don’t see people dropping dead of a heart attack,” her mother ...