She proved it at the Masters Games by winning five gold medals in endurance sports in the women's 40 to 45 grade.
Cuthbert (44), a physical education teacher at Kaikorai Valley College, won gold in the rail trail duathlon, road duathlon, 50km cycling road race, 10km running road race and the half-marathon.
Gutsell went hard from the start and had a 16sec lead when the half-marathon runners left the Caledonian Ground yesterday.
It had increased to 49sec after the completion of the short lap around Logan Park.
When she started on her fitness programme, Cuthbert weighed 80kg and she faced the starter in the half-marathon yesterday at 60kg.
"I only started running at the age of 37 after I'd had my two children," she said. "It's gradually come off over the last seven years."
The combined benefits of running and cycling and some toning work in the gymnasium have given her a new look.
She also watched her diet.
"I had a niggle in the hamstring for a while but this has come right," she said. "I feel fit and strong at the moment."
She finished yesterday in 1hr 30min 27.53sec and was followed home by Jude Patterson (Lawrence) in 1hr 42min 09.96sec, Sandra Brocks (Dunedin) in 1hr 49min 15.49sec and Janine Wright (Dunedin) in 1hr 52min 54.78sec.
The men and women race together and Cuthbert finished 10 overall.
The men's event was dominated by Southland runner Ricky Gutsell, of Gore.
Gutsell won in 1hr 18min 29.42sec and was followed home by Bruce Halligan (Invercargill) in 1hr 21min 48.30sec, Murray Dempster (Waikouaiti) in 1hr 22min 16.68sec and Peter Frew (Dunedin) in 1hr 24min 09.99sec.
Gutsell (49) won all three road races - 5km, 10km and half-marathon - in convincing fashion.
He started training for the Masters Games in November after winning the Southland Marathon in 2hr 41min.
Gutsell burst out of the blocks and had a lead of 16sec when the runners left the Caledonian Ground. He completed the first of the two full laps in 43min 16sec and had extended his lead to 2min 53sec over Halligan and Dempster.
"It felt pretty good today," he said. "All I wanted to do was to maintain my form and just keep going."
Halligan (45), an environmental planner, applied pressure with 2km left to break away from Dempster.
He also won a silver medal in the 5km run in his sixth Masters Games.
The best of the over-70s runners to finish was retired secondary school teacher Peter Ruhen (71), of Dunedin, who was 39th in 1hr 55min 59.86sec.
Dunedin's Barbara Dixon Grant (59), the oldest female in 2150the half marathon, took up long-distance running as a way to cope with family grief when she lost her 13-year-old son, Kahu, to leukaemia.
She found running therapeutic and has completed the Kepler Challenge three times.
She was the 12th woman home yesterday in 2hr 02min 42.50sec.
Three competitors over 80 completed the 10km walk: Charlie Collette (Invercargill) in 1hr 22min 40.53sec, Dunedin's Isobel Hatherly in 1hr 25min 46.78sec and Agnes Hodges (nee Haig) in 1hr 35min 49.66sec.
Barbara White, in her 15th New Zealand Masters Games, was first home in the walk in the women's 70 to 74 grade in 1hr 14min 53.28sec and Mary McFarlane won the 75 to 79 grade in 1hr 33min 14.04sec.
