Cardiac hypertrophy is defined as an increase in heart weight: body weight (HW:BW) and occurs in two different situations. Cardiac hypertrophy can be caused by exercise (physical induction) or heart disease (pathological induction), each caused by phosphoinositide 3-kinase (PI3K). Swim training was performed on female and male C57/BL6 mice. The mice were subjected to a swimming schedule that started with a 5 minute swim twice a day for a week, then increased to 10 minutes for two days and increased in 10 minute increments every other day until a 90-minute swim session was reached and maintained for 4 weeks. The mice swam 7 days a week throughout the study. The HW:BW of the males increased by 32 percent, but the females only increased by 8 percent. We concluded that swim training does significantly cause cardiac hypertrophy in male mice.