serial killers halloween physiology

You’re walking in the woods. Alone, with no cell reception. Suddenly, there’s a rustling in the bushes. Maybe it’s the newly revamped Michael Myers, or actual cannibal Shia LeBeouf. Whoever it is, they’ve got a weapon, and they’re coming for you. As the soon-to-be killer sprints from the shadows, one question determines your fate: Are you fit enough to make it out alive?

Carol Ewing Garber, Ph.D., a Columbia University professor of movement sciences, tells Inverse that escaping will be much harder than it seems, even for the physically fit.

“It just takes a lot more energy to run the body under those circumstances,” she says, explaining the many different biological factors at play that may impact the odds of survival. Here, she outlines how to outrun a killer, how much they’ll struggle to catch you, and what you can do to prepare yourself.

You know, just in case.

Escaping a Killer: Physical Factors

The odds of survival largely come down to whether it’s the killer or the victim that’s expending the most energy in a chase. The victim doesn’t have the burden of carrying a heavy weapon, like a chainsaw, which is a plus. But it might not make up for the main energy suck: running in fear.

“It’s hard to know exactly how fast someone would be running. But I would be running as fast as I humanly could run, so your usual runner might be going somewhere around a six-minute mile,” Garber says.

Garber estimates how much energy it actually takes to run from a killer using the Compendium of Physical Activities, a database of energy expenditure estimates for certain activities. Cross-country running requires nine METS (the metric used to measure energy expenditure) — that is, nine times the energy expenditure of sitting around doing nothing.

Whereas “walking for pleasure” requires 3.5 METS, running a six-minute mile to escape from a killer requires around 14.5 METS on a flat surface. Assuming the terrain is rocky (isn’t it always in horror films?), Garber suggests that the actual amount of energy expended would be slightly higher than 14.5.

But on top of regular physical expenditure, there’s the added hardship of running under high-stress conditions.

Horror films have an effect on the brain as well.

Escaping a Killer: Hormonal Factors

The stress of knowing that dismemberment by a psychopath is imminent activates the sympathetic nervous system, also known as the body’s fight-or-flight response. Its activation stimulates a sharp increase in adrenaline, a hormone that dilates pupils to improve vision and help the body convert stored glucose into quick energy to make an escape — like a quick sprint into town to the nearest police station.

“I would say whenever there’s a case where there’s a lot of stress and fear, any exercise with running or carrying will probably take more energy,” Garber says. “Your adrenaline will be flowing, and heart rate and breathing will increase just from the stressful experience. It would be more than if you were just running without someone chasing you.”

But over the course of a long night of fleeing, the constant rush of stress hormones will take its toll — especially if safety is far away. For a typical untrained individual, Garber predicts that adrenaline will provide a boost for up to ten or 15 minutes, depending on how terrified the victim is. Unfortunately, an untrained body isn’t positioned to continue to deliver oxygen to the muscles with enough efficiency to maintain the sprint.

“Where they’re really frightened, the adrenaline might help them go a bit farther, but I would guess they probably would have to stop. That person’s probably not going to make it,” she says.

Running with a chainsaw requires more energy than running without a weapon 

Good Thing Chainsaws Are Heavy

All is not lost for those who haven’t been training to escape death. Even the most physically fit killer has to expend extra energy by wielding a weapon during the chase.

The Compendium of Physical Activity shows that it takes 5 METS to walk on level ground while carrying a 15-pound load. It also notes that gardening with power tools (it lists a chainsaw as an example) requires 5.8 METS. So, given that the killer must also chase the very scared victim at a six-minute-mile pace, this additional energy expenditure will certainly slow them down. This may give the victim, spurred on by the sympathetic nervous system, a brief advantage out of the gate.

As we learn anecdotally from movies like The Texas Chainsaw Massacre, killers occasionally pause the chase to dismember other victims. Perhaps you were not alone in the woods after all!

The closest activity to dismemberment in the Compendium is “hunting large game, dragging carcass,” which requires 11.3 METS of energy. The bodies of your friends — if enough of them were were with you in the forest — could represent a serious energy suck for the killer, allowing a savvy would-be victim to escape.

Taken altogether, the data suggest that for most untrained people, context is everything. At the beginning of the chase, the killer is likely expending slightly more energy than the victim while wielding the chainsaw. But after that crucial 15-minute mark, an untrained victim may begin to feel the consequences of muscles unaccustomed to sustaining high-intensity exercise, allowing the slow and steady killer to close in. In that case, the only hope is that the killer catches someone else first and expends some extra energy that way.

How to Train For Survival

Not all is lost, says Garber. Some basic exercises may help improve the chances of survival. She suggests focusing on endurance exercises, similar to those used for half-marathon training. Begin by increasing the distance — building a base to ensure that the body can make it past that 15-minute mark.

But simply increasing distance isn’t enough, she warns. Adding some high-intensity intervals or sprints might be what makes the difference between being caught and making it the last 100 feet to safety.

Over the course of the night, stress starts to take its toll 

“If you’re already a runner, increase your distance in a gradual way,” Garber says. “But also add some high-intensity intervals, so that way you have the ability to change speeds. As the guy is getting close, you need to sprint to get ahead of them.”

It is, of course, entirely possible that the murderer might finally close in for the kill. If this happens, having done some muscle strengthening activities like lifting weights will come in handy, says Garber. But seeing as hand-to-hand combat is the situation you most want to avoid, the best chance of survival comes from, at least occasionally, going for a quick run — just in case.

Photos via Giphy (1, 2)