Triathlon 6-pack: Together again, fitter than ever

This week, the CNN Fit Nation Triathlon team is in Kona, Hawaii, for a week of intense training. Follow along on The Chart and on Twitter, @CNNFitNation

One of the most rewarding parts of planning the Fit Nation Triathlon Challenge is watching our 6-pack be transformed from largely sedentary to seriously competitive amateur athletes.

When we first met this year's group in early February, we were very impressed with the work they had already done to change their lives. Some had lost weight before getting to us. Most had started to exercise regularly, and they were all starting to adopt better eating habits.

But, the changes they've made since then have been nothing short of remarkable.

Before he joined the team, Joaquin Brignoni, a father of four, could barely find the time to exercise in between dance practices and PTA meetings.

Yesterday, he biked 18 miles on the extremely hot and windy "Queen K" Highway – site of the Kona Ironman World Championship – at the front of the pack.

Right at his side the entire time, was Dr. Scott Zahn. Four months ago, he had just been put on 3 blood pressure and cholesterol medications.

Yesterday, more than 40 pounds lighter, he knocked out a 4-mile run, an 18-mile bike and a 30-minute swim along with his teammates.

And that was only day 1.

Stay tuned for updates on the rest of the athletes throught the week.