Paramedics and fitness experts are warning people with new year's resolutions to be careful about exercising after two people suffered heart attacks at local gyms this week.

Paramedic spokesman J.P. Trottier says cardiac arrest calls go up during the winter months, not only at gyms, but at arenas as well. (CBC)

Every day, on average, paramedics respond to about four cases of sudden cardiac arrest outside of hospital, said paramedic spokesman J.P. Trottier.

But in winter months, especially after the holidays, the number of calls rises.

"We do see an increase in our calls for these types of things during the winter, in both gyms and arenas, fitness centres and so on," Trottier said.

Dangerous to work out too hard, too early

Pascal Imbeault, a human kinetics professor at the University of Ottawa, agreed.

"It's typically common because after the Christmas period … we have a lot of [good] intentions and we're tending to go harder than we should go, and this is the reason why some accidents … are occurring," Imbeault said.

When starting a fitness regimen, Imbeault said it is important to choose a gym with certified staff and to go through a physical activity readiness questionnaire with an instructor.

Both heart attacks earlier this week happened at gyms with certified staff — one at GoodLife Fitness and one at the Ottawa Athletic Club.

Pascal Imbeault, a University of Ottawa professor, says while it is dangerous to work out too hard, it is better to be active than not. (CBC)

The questionnaires are available online, Imbeault said.

If people do not have personal trainers, they should get the approval of their family doctors before starting any exercise program, Imbeault said.

And for people training at home, Imbeault said it is a good idea to make slow progress and gradually increase the intensity of workouts.

Age of cardiac arrest victims getting lower

Trottier also said the age of cardiac arrest victims is getting lower.

"It certainly seems like that," he said. "Thirty years ago, it was odd to hear about a call where a man in his 40s had a sudden cardiac arrest, and it seems to be more prevalent now."

While no formal studies have yet been done, Trottier said sometime this year paramedics could go over their cardiac arrest data from the last several decades.

But despite the dangers of working out too hard, Imbeault said it is better to be active than not.

"Please be active," Imbeault said. "I know this is the best time of year to start good resolutions. And if you do it well, you're going to do it forever."