Part 1.
Lincoln is a 50-year old runner who, over the past five years, has completed five half-marathons and four marathons. He regularly runs six to seven days a week, totaling 30–50 miles per week. For his fiftieth birthday Lincoln decided to participate in the Silver Rush 50-mile run. This 50-mile out-and-back run started at an elevation of 10,000 feet in Leadville, Colorado, and ascended 7,400 feet over four peaks, with the highest pass at 12,200 feet. The average ambient temperature during the race was 80°F.; the race had 600 participants.

The first half of Lincoln’s run progressed well, and he made it to the turnaround checkpoint in just under six hours. He was eating and drinking according to plan, but noticed that it took a very long time to chew and swallow his last solid energy bar as he approached the turnaround checkpoint. As he was changing shoes and replenishing his supplies from his drop bag he became nauseated and barely make it to the portapotty before vomitting. He sat next to his drop bag, still nauseated, for ten to fifteen minutes, and began to question whether or not he could continue the race.

He ultimately completed the race, running and walking the last 25 miles in seven hours and 45 minutes, ascending 3,700 feet and running at an average elevation of 10,000–12,000 feet. He ran the last two hours consuming no food and less than one liter of water.

After crossing the finish line he proceeded, as required, straight to the medical tent, discussed his situation, and was administered sips of Coke, pretzels and part of a sandwich. The paramedics working the race assessed his situation and sent Lincoln on his way back to his hotel.

Patient History:

• Patient is five foot nine inches tall, weighs 165 pounts, and has less than 3% body fat.
• Pre-race physicals (conducted six months and one month before the race) were unremarkable.
• No history of heart, cardiopulmonary or G.I. problems.
• Stress tests administered during pre-race physicals were both normal.
• Medications: OTC vitamins, glucosamine-chondroitin sulfate, and one baby aspirin a day.

What is your diagnosis for this patient?