When Gary Blakie was 12, he was diagnosed with type 1 diabetes. It hasn't stopped him from representing the UK in the World Triathlon Age Group Championships.
How did you react when you were diagnosed with type 1 diabetes?
"I was diagnosed when I was 12, on a family holiday in the US. I'd been feeling awful and going to the toilet a lot, but I didn't know anything was seriously wrong.
"It was a shock, although in the first few days I knew nothing about diabetes or what the diagnosis meant."
Did it change your attitude to sport and physical activity?
"Not really. I just wanted to carry on doing what I did before. I wasn't involved in any serious sport at that time, but my dad and uncles always did triathlon and my mum is a sports therapist, so sport has always been a part of my life.
"When I was 13, I started running with my dad. I had only recently learned how to control my blood sugar, and now I had to try to keep my levels steady while I exercised (physical activity can cause blood sugar levels to fall too low or rise too high). Not surprisingly, I got it wrong a lot at first, but I learned each time."
Surely diabetes made it difficult to train for serious athletics?
"I got into triathlon through running. I did my first triathlon in 2001, and progressed from there.
"During training, the main problem is managing your blood sugar levels around your regime. When I started, there wasn't a lot of information available, so I did a lot of guessing. I experimented with insulin injections and foods at different times around exercise. I always aimed to keep my blood sugar level steady throughout a period of exercise.
"I learned a lot about how my body responds to different types of activity and different foods. One hour of swimming, for example, tended to lower my blood sugar level by about 3mmol/l. So if I began the swim with a level of around 5.6, I guessed that I'd need something to eat halfway through.
"As anyone with diabetes knows, if your blood sugar becomes too high you'll feel tired and thirsty, and your heart rate will increase a lot. If it's too low, you'll have very little energy. Neither are any good if you want to run, swim or cycle as fast as possible."
Did you have problems during the early races?
"Yes. During my first triathlon, I stopped at intervals and measured my blood sugar levels. Obviously this isn't ideal: 30 seconds in a triathlon can cost you five places.
"It took me three years to find a regime that was right for me, and didn't involve stopping for tests or insulin during the race.
"For example, in the sprint triathlon I swim 400 metres, then do a 13-mile bike ride, followed by a three-mile run. At the start of the race my blood sugar would be around 5.6, which is great, but by the end it was 19 or 20.
"So I decided to take less long-acting insulin and instead take a dose of short-acting insulin before the race. This stopped my sugar levels climbing so high. But then I starting having hypos, as my blood sugar became too low."
Now you have a regime that works?
"Yes - 2005 was the year when I finally got my insulin regime right. In that year, I did about eight races. The best part was racing for the UK team at the World Championships in Hawaii. That was a great feeling.
"My regime is different, depending on the race. For the sprint triathlon, I'll take my normal 15 units of long-acting insulin the night before. In the morning, I'll take an extra 15 to 20 units of long-acting insulin two hours before the race, because background insulin takes two hours to start working. This way, if I start with a blood sugar level of 5.6, I'll finish with a level of around 6.4. These days, I know I can rely on that.
"I don't eat heavily before the race. Eating a little and often is good. I'll usually carry a snack bar and eat a little bit every 30 minutes during the race to keep my glucose levels up.
"But other people with diabetes will need to find what works for them. The important thing is that it's possible play sport with diabetes, and that there are benefits beyond sport. Once you know how your body responds to activity and food, it helps you manage your diabetes throughout the day."
How can other people with diabetes discover what works for them?
"My method was guesswork. But these days there are good sources of information out there that can help. Take a look at the Runsweet website, where there are lots of shortcuts and tips on how to manage diabetes during all kinds of physical activity."
What is a typical training day now?
"I'll go for an early 30-minute swim at 6.30am. I don't eat beforehand, and I'll test my blood sugar prior to the swim, to see if I'll need to eat food halfway through the session.
"After work, I go for a 90-minute run. Again, I'll test my blood sugar beforehand and adjust what I eat accordingly. I always bring food with me when I run, in case my blood sugar falls really low. Ideally, you'd bring your insulin kit with you, but I have enough experience to know that my levels won't get really high, so I don't need the kit any more."
Do you have to stick to a special diet?
"Not really. I don't eat burgers and chips or curries. I eat pretty healthily, but I don't have a special diet. With diabetes, you just have to be aware of the consequences of what you eat. You can have a bit of chocolate occasionally, but if you eat too much you know your sugar level will rise too high."
What's your message to other sportspeople with diabetes?
"I am proof that people with diabetes can perform in high-level sport. You simply have to find out what regime works for you and then go for it."
Article provided by NHS Choices