Have you ever wondered how scientists study the human body’s responses to extreme conditions such as severe blood loss? Science experiments don’t always involve expensive equipment, glass beakers and dangerous chemicals. In fact, one of the coolest experimental techniques in physiology requires just two common household items: a vacuum cleaner and a box big enough to fit a human (well, at least the lower body)!

Lower body negative pressure (LBNP) allows physiologists to study how the human body reacts to severe bleeding—in a safe and controlled way. It’s surprisingly simple. Participants lie down on a bed with their lower body inside an airtight box, then the researchers use a vacuum device, such as a vacuum cleaner, to slowly suck air out of the box to create a negative pressure inside.

Just like sucking water through a straw, this negative pressure pulls blood volume down into the legs of the participant, so less blood flows into the heart and brain. At this point, the body begins to respond as if it’s actually losing blood.

You may wonder how simple and mundane items such as a box and a vacuum cleaner meaningfully simulate something as drastic as actual blood loss. The facts about LBNP may surprise you:

• The technique has been used in scientific research since the 1950s.
• LBNP can reduce the amount of blood your heart pumps by up to 50% and the blood going to your brain up to 30%, mimicking actual blood loss.
• A study directly comparing LBNP with removal of 25% of blood volume showed very similar physiological responses. This study showed that scientists can learn about how people might respond to blood loss and different treatments without having to actually take blood out of a volunteer’s body.

The LBNP procedure is very safe. As blood is only temporarily moved into the legs and isn’t being removed from the body, simply turning off the vacuum makes the blood immediately return to the rest of the body. The study participant feels “normal” again within a few minutes—their heart rate will slow down, and their blood pressure and brain blood flow will increase back to resting values.

Our laboratory studies blood loss and develops new approaches to monitor and treat blood loss injuries. I’ve been in our LBNP chamber many times as a research participant and as a “test pilot” as we develop new protocols. Everyone’s experience with LBNP is a little different, but I always tell people it feels like the head rush you get while riding a roller coaster! This is one of my favorite parts about being a human physiologist – I get to work with human volunteers using a cool and unique technique like LBNP and get a front seat observing their reactions to that experience (while also monitoring how their physiology responds in real time). And all that can happen from the creative use of just a vacuum cleaner and a box!

So, the next time you see a coffee mug, air fryer, hair dryer, or any other regular household appliance, ask yourself: Is this the key to the next physiological breakthrough waiting to happen?