Every year, we hear news reports of people, usually older men, having heart attacks or experiencing sudden cardiac death after shoveling snow. In response to these alarming reports, we initiated a series of studies at Beaumont Hospital to better understand what’s happening to the heart during snow removal. We found that, in some people, outsourcing this strenuous activity can be lifesaving.
High heart rate, blood pressure
During the first investigation, we monitored heart rate, blood pressure, and oxygen consumption, a measure of energy expenditure, in 10 healthy, inactive men while they were clearing a 4-inch-high tract of heavy, wet snow for 10 minutes. The heart rate and blood pressure of most of our subjects catapulted to dangerously high levels that were comparable to or higher than the maximum values the same people achieved when exercising to exhaustion during maximal treadmill testing. As expected, men with the lowest fitness levels during treadmill testing had the highest heart rates when shoveling.
Energy expenditure during shoveling was nearly six times higher than energy expenditure at rest, which is equivalent to the energy cost of playing singles tennis. Moreover, the average study participant lifted and threw nearly a ton of snow (12 shovels per minute x 16 pounds per shovel x 10 minutes = 1,920 pounds). That’s the weight of a mid-size automobile.
Snow throwers are risky, too
In a second study, we reported on 20 men (ages 55 to 77) who had experienced heart attacks and were admitted to our hospital’s emergency center over a 12-day period of blizzard conditions.
Five of the men had been clearing snow. All of the men engaged in snow removal had a history of heart problems or coronary risk factors, including a sedentary lifestyle, and four of the five were classified as obese. Interestingly, two were using an electric snow thrower.
We saw additional snow-thrower-
related deaths in our third study, when we reviewed death records from three counties in the weeks before, during, and after two heavy snowfalls that occurred in the greater metropolitan Detroit area. Of the 271 people who experienced sudden cardiac death, 36 (33 men, three women) were engaged in snow removal. Four of them were using an electric snow thrower.
We discovered through these studies that at least five characteristics of snow removal may contribute to the disproportionate demands on the heart:
- the relative inefficiency of arm exercise;
- working in an upright posture when the legs are frequently motionless;
- isometric (static) exertion;
- breath-holding (expiratory strain);
- exposure to dangerous cold air/wind chill factors.
Are you at risk?
We found that the people with the highest risk of cardiac complications during snow removal were older than age 45, had one or more major coronary risk factors, a history of heart problems (exertional chest pain, previous heart attack, bypass surgery, or coronary angioplasty), or had experienced symptoms that suggested a cardiac problem.
If you fit this description, don’t take the risk: Paste a note to your snow shovel or electric snow thrower that reads, “Warning: Use of this instrument for snow removal may be hazardous to your health,” and hire a snowplow service or neighbor to clear your driveway this winter.
