Field & Stream Online Editors
Field & Stream Online Editors

Consider this: You go into the woods this fall, but instead of dragging out a deer, your friends end up dragging you out, just as dead as the deer would have been. No, you weren’t shot; the odds of that happening are almost nil these days. Your own heart killed you.

Medical science is just learning that deer hunting is the perfect way to trigger a heart attack. With a combination of factors found in no other sport, it can cause traditional coronary blockage¿¿¿style heart attacks, and more-it can explode weakened arteries, block oxygen flow from the lungs via blood clots, and cause such electrical chaos in cardiac muscle that the frenetic pump in its final moments resembles a bag of worms. It’s also fun, so those who take part in it lose all sense of what they’re enduring and wildly exceed their own physical limitations.

**Prime Candidates **
“Deer hunting is unlike any other single physical activity,” says Susan Haapaniemi, a researcher and registered clinical exercise physiologist at William Beaumont Hospital in suburban Detroit. “Not only does it elicit tremendous levels of sudden, strenuous exercise, which is itself a well-documented risk factor for cardiac death, but it also leads to a huge rush of adrenaline and other fight-or-flight hormones. This rush just builds and builds over the course of the hunt.”

Though no one keeps exact statistics, Haapaniemi says that many more hunters die each year from heart-related problems than from any other cause. “Every hunter,” she says, “has a story about a friend found dead from a heart attack.”

In states like Michigan and Pennsylvania, about a million hunters take to the woods each deer season, and about a quarter of these are men 45 and older-prime candidates for the Cardio-Reaper.

It’s true that hunting poses the greatest risk to those with either existing heart disease or heavy-duty risk factors (or both), but even apparently healthy people can be vulnerable. Dean Wolz, M.D., a Pittsburgh-based cardiologist and lifelong big-game hunter, who says that nearly half his patients are deer hunters, explains, “We’re finding heart disease earlier than we ever used to think was likely. Younger men and women are having heart attacks in their 20s, 30s, and 40s.”

This deserves repeating: You do not get a free pass from death if you’re under 50. If you’re planning on hunting, especially in remote areas far from emergency medical care, consider seeing your doctor first about a stress test.

Hunter Heart Study
In an effort to document the physiological toll that deer hunting takes, Haapaniemi recruited 25 male volunteers from the Great Lakes Hunting Club in Rochester Hills, Michigan. “We walked in,” she recalls, “and the room was thick with cigarette smoke. These guys were loading up their plates with beef and gravy.”

Perhaps not surprisingly, the majority of these hunter volunteers had already been diagnosed with atherosclerosis (hardening of the arteries) or had at least two major risk factors for heart disease. Before they went into the field, Haapaniemi gave each man a treadmill stress test in the lab, during which she measured their pulses during maximum exertion as well as the electrical activity in their heart muscles.

On the morning of the hunt, each man was rigged up to a Holter monitor-a Walkman-size device that records every heartbeat and rhythm. Later, when the day’s data was analyzed, even Haapaniemi was shocked to find just how grueling a day spent in the woods can be. Each individual phase of a hunter’s activities came with its own heart risks, cumulatively increasing the burden of the steps to come:

**(1) Walking to the stand. **The American Heart Association recommends that a heart rate “target zone” for exercise should be between 50 to 75 percent of your maximum. (If you haven’t had an “exercise to exhaustion” stress test yet, youu can get a rough estimate of your own upper limit by simply subtracting your age from 220.) Merely walking to the tree stand in the early morning caused the hearts of 21 of the 25 volunteers to climb to an average of 94 percent of their maximum-“well above,” says Haapaniemi, “what we recommend for training in the gym.”

Likely reasons ranged from rough terrain to cold weather (which constricts peripheral blood vessels, forcing the heart to work harder), to the fact that those on heart medications had just swallowed their pills (so meds like beta blockers, which limit how fast the heart can beat, hadn’t had a chance to kick in yet).

**(2) The long wait. **Once on their stands, the hunters stopped moving for up to several hours. “When you’re either standing or sitting motionless for long periods of time,” says cardiologist Wolz, “blood clots can form in the legs of vulnerable individuals.” These can then dislodge during subsequent exercise or excitement, travel to the lungs, and trigger a pulmonary blockage. This, in turn, can cut off oxygen flow to the right side of the heart, often killing the victim.

To reduce their odds of forming leg clots in the first place, Wolz gives his hunting patients the same advice he recommends to passengers immobilized during long plane flights: periodically flex your ankles, walk in place, and do isometric leg contractions to keep blood moving through the veins.

**(3) Buck fever. **The appearance of a deer caused the men’s heart rates to soar, on average, to 114 percent of maximum. This may seem impossible, but the flood of adrenaline-like hormones and neurotransmitters, says Haapaniemi, can stimulate hearts well beyond the highest level measurable in the lab. One hunter’s heart rate jumped in moments from 78 to 168 beats per minute. After the shot, it can sometimes escalate even higher-in one man, up to 118 percent of his treadmill max.

And all of this is made worse because it comes so abruptly. With most forms of exercise, Haapaniemi says, participants work their way into it with a warm-up period, but “none of this happens with deer hunting. You’re not warmed up, you’ve been sitting very still, you’re usually out in the cold so your peripheral vessels are constricted. Then, without warning, you’re asking your body to do sudden, very strenuous exertion.”

(4) Tracking and dragging. Once they locate the deer, the most demanding physical part of the hunt begins: getting it back to the car or truck, a process that can often take an hour or longer and cause the heart rate to rise to 116 percent of peak. “I’ve done all types of manual labor in my life,” says Wolz. “I played football and lifted weights, but nothing has come close to dragging 100 to 200 pounds of dead weight on dry ground up a hill.”

Most men 45 and over know that it’s unwise to shovel heavy wet snow, and they don’t hesitate to pay a neighborhood kid to do it for them. But there’s something about hauling your own deer out of the woods that seems to tap deep into male machismo. Wolz pushes his patients to show some sense. “It’s just like everything else as you age,” he says. “Try not to get in bar fights, drink too much, or drag your own deer.”

“The thing about dragging a deer,” adds Haapaniemi, “is that it’s not just an isolated activity. It’s the final stage in a whole crescendo, during which the excitement and adrenaline have been building.”

Despite the rigors of hunting, Haapaniemi is not urging people to give up a sport they love. Rather, be smart about how you hunt. “Some of our volunteers had scar tissue in their heart muscle from previous heart attacks. I suggested they take their sons or buddies out, and let them drag the deer. If you’re sensible about it, even hunters with very compromised hearts can still enjoy hunting.”