The results of the survey of 2000 people by insurance company Southern Cross Health Society showed people from Dunedin were the nation's most frequent exercisers, with 47% of Dunedin respondents saying they exercised at least four times a week.
Wellingtonians were close behind and Aucklanders were the country's least frequent exercisers, with 45% exercising once a week or less.
Crystal Graham, from Les Mills Dunedin, said it was great Dunedin people were the most active.
However, it was not surprising, because Dunedin was such a safe city and environment in which to exercise and she believed there was a real understanding among residents of the benefits of exercise to a person's mental health, as well as physical health, she said.
Mother of two Tash Columbus (35) said she joined the gym in May last year because she was in a bad place and wanted to lose some weight.
Exercise had turned her life around, she said.
She now went to the gym or ran twice a day, six days a week, and spent about 14 hours a week in total working up a sweat.
Fourteen kilograms lighter and physically and mentally stronger than she had ever been, she said her life was completely different. Her results had einfluenced her husband to also join the gym.
''It's been hard, but nothing worth having comes easy, and I just love it. It's addictive. The more you do, the more you want to do.''
The survey found the under 30s and over 50s were the most likely age groups to exercise.
About 24% of people said they exercised at least once a day.
Southern Cross Health Society chief executive Peter Tynan said although there were positives, the overall results of the survey showed more than a quarter of respondents exercised less than once a week or not at all and that was a ''huge worry'' for the nation.
''Regular physical exercise can help reduce the risk of chronic conditions such as cardiovascular diseases, cancers, obesity and diabetes. Preventive action through exercise can help to save lives and tax dollars.''