The 59-year-old East Kilbride man had a double heart bypass last May and as well as marvelling at the wonders of medical science he is delighted to be back in the swim.
Dougie has covered the distance of 27 marathons, about 715 miles, over the past seven years in the pool.
He is a regular at Glasgow Club Tollcross, which will host the swimming events at this summer's Commonwealth Games, and jumped in at the deep end back in 2005 when he had seven stents inserted to improve his heart condition.
He said: "I took up regular swimming, which helped me lose weight and improve my overall health.
"I was fine for eight years, but last Easter instead of swimming 40 lengths an hour I could only manage two.
"When I experienced unusual sensations in my chest I went straight to the hospital where scans showed I needed a double heart bypass operation.
"This came as a shock as I considered myself relatively fit."
He had surgery on the same day as his 30th wedding anniversary. The best present his wife Margaret could have was a husband on the way back to good health.
Dougie said: "I wasn't allowed to do any exercise until November.
"I'm now back swimming for 45 minutes, doing 30 50-metre lengths.
"Before the operation I was doing 40 50m lengths in an hour so I know I'm at the stage where I can do the full hour but I'm gradually building up to that."
As well as swimming, walking has also helped his recovery and he has covered 403 miles since the operation, taking it at a steady pace of just one and a half miles a day.
In the water, so far this year he has swum 18 miles.
The walking has been good for his legs but he says he has to work on building strength in his arms now, and that's why swimming is so good.
He said: "Swimming is brilliant, it works out the whole body in one exercise. Now I'm back in the pool three times a week."
Dougie said he only learned to swim when he was married and in his late 20s.
His wife Margaret is originally from Hong Kong and she encouraged him to take swimming lessons before going home on holiday because she knew they would be going to the beach.
Over the years Dougie went to the pool with his son Richard when he was growing up.
Now he believes it has helped immeasurably in his recovery back to good health.
"It's amazing what anyone can do for themselves by getting active and trying some regular exercise," he says.
Evening Times Active 2014 aims to improve the health of Scots in the year of the Commonwealth Games and build a lasting legacy of physical wellbeing.
Working with partners Glasgow Life, NHS Greater Glasgow and Clyde and SportScotland we'll be creating exciting opportunities for individuals, communities and businesses to get active as we bid to improve the health of as many people as possible in the community.
The message of this campaign is that even the smallest of changes in activity and lifestyle can make a huge improvement in health.