The common belief that the blood going to your digestive tract after eating steals the blood needed to keep your arms and legs pumping during swimming is unfounded, says Mark Messick, MD, a family medicine doctor at Duke Primary Care Timberlyne.



According to Dr. Messick, the body does supply extra blood to aid in digestion, but not enough blood to keep your arm and leg muscles from properly functioning. Your biggest danger related to eating and swimming is probably a minor cramp.