The Windsor Cardiac Centre is now monitoring 250 high-risk heart patients across the country, using satellites.
The real-time surveillance can detect the warning signs of heart attack.
"The body tries to give you a lot of hints, for weeks and weeks before patient actually collapse," said Dr. Wadea Tarhuni.
The monitoring device is called a cardiophone. It is a wireless device that combines heart monitoring and cellphone technology.
From Windsor, Ont., experts at the centre monitor the patients' every heartbeat in real time.
He said one group at a particularly high risk is middle-aged men who play hockey, especially those who only play hockey once a week.
Research shows players between 40 and 60 are at increasing risk of heart attack - especially if they're mostly sedentary the rest of the week. Doctors say hardening of the arteries may go undetected until a player overexerts on the ice.
"Playing hockey, professional or recreational, they're putting a lot of stress on their heart and their brain and they might develop heart attack or stroke," he said.
Tarhuni encourages exercise, but said before someone takes on a sport so intense, they should speak to a doctor first.
Tarhuni said people older than 40 should go to their doctor and request a full cardiac screening, including stress test, before joining a league or exercise program.
Wayne McCaw, 47, saw the effects hockey can have.
"A good friend who plays hockey had some heart issues during a game," he said. "He became short of breath and was exhibiting some odd behaviour and ended up having a double bypass as a result of it."
Each year, approximately 7,000 people in Ontario will have a heart attack.
According to the Windsor Cardiac Centre, up to 85 per cent of cardiac arrests happen at home or in public places. Almost half of cardiac arrests are witnessed by a family member or friend.
There is now a growing trend among doctors of "prescribing" exercise rather than simply suggesting it.
The head of the Heart and Stroke Foundation's stroke recovery centre welcomes the trend.
Dale Corbett said specific exercises with specific instructions on how and when to do them lead patients to actually stick with them.
"It's going to be a very important tool in getting people to exercise more and make it part of their daily routine," he said. "And that's really what we have to get back to, or get to in a lot of cases."
Corbett notes that exercise is beneficial for physical and mental health and longevity.