Why Do Humans Need to Warm Up Before Exercising?

Simon A. asks: Why do people need to warm up before exercise? Many animals don’t seem to have such an issue, like a cat going from completely still to sprinting after prey. So what exactly is going on internally that makes doing some activity with a warm up first less injury prone than if one just jumps into it? Or is it just a myth that we should warm up and it doesn’t actually do anything?


There isn’t a respectable personal trainer in any sport that doesn’t stress the importance of warming up before you begin a workout or athletic endeavor. Most people seem to know you can prevent injuries and allow for better performance should you follow their advice. So, what about warming up allows for these benefits? What exactly is going on in the body when you more slowly prepare it for strenuous activity, rather than just jumping right into it?

The simple answer is that warming up increases blood flow to muscles, allowing for an elevated amount of oxygen and nutrients to be delivered. This prepares the muscles for a rise in workload. Warming up will also begin raising body temperature, which helps you utilize oxygen better. That boost in blood flow also serves to prime the nerves supplying your muscles with impulses, increasing the quality of performance.

Along with the blood flow and temperature benefits, an appropriate warmup also prevents injuries by providing greater range of motion, while simultaneously improving the lubrication of joints, allowing for better movement. Lastly, many trainers posit that a good warm-up before any event where performance is valued can help mentally prepare you for the task to come.

So that’s the high level view of it all. But what actually is going on internally here?

First, let’s look at what gives your body the ability to deliver more oxygen. It seems common sense that if the average heart rate is around 70 beats per minute, and each beat ejects approximately 70 ml of blood, then your heart will circulate about 4.9 liters every minute. The higher the heart rate, the more blood will be pumped. During extreme exercise, studies have shown your heart can pump up to 30 liters per minute! The question then becomes- why does slowly increasing heart rate, and by extension blood flow, vs. suddenly leaping into action and rapidly increasing blood flow allow for better performance, while reducing injury?

When your muscles are working harder than normal, they require more oxygen and nutrients. This provides all the electrolytes responsible for the electrical impulses providing for muscle contraction and glucose to start a cascade of chemical events leading to the production of a molecule called Adenosine Triphosphate (ATP). ATP is responsible for moving those electrolytes (and other molecules) in to, out of, and around your cells. Oxygen is also essential in creating ATP.

When oxygen is used to create ATP, it’s called aerobic metabolism. When you increase the work of your muscles past the point oxygen can make the appropriate amount of ATP, your cells begin to use glucose and acids to make more, also known as anaerobic metabolism.

The byproduct of anaerobic metabolism is the increased production of an acid called pyruvate, which also creates lactic acid. Those acids will cause all kinds of damage to your cells. The resulting pain that follows leaves every marathon runner in agony the next day. The maximum heart rate at which your cells can use oxygen to make ATP is known as your Vo2max.

What does all this chemistry have to do with warming up?

Studies have consistently…

Adding Ice to Medics’ Kits Could Help Patients Survive Blood Loss

ice cubes
Ice cubes

Blair Johnson, a physiologist at the University of Buffalo, recently discovered a method to help balance out Blood Pressure. He discovered that if a bag of ice (or at least ice cold water) is placed on the fact, it forces blood to rush to that area. This method, researchers warn that this isn’t meant for a long term fix, just a temporary patch for when a hospital can be reached in short order. So, if they were to add an ice pack to Medic’s kits, it could help out in a severe bleeding situation.

Medics may have a new tool to help severely injured patients: ice. A bag of it on the face could help to keep blood pressure up in those suffering severe blood loss.

Keeping a cool attitude helps when handling an accident victim who has lost a large amount of blood. But keeping patients cool might also help, a new study finds. It might save their lives.

Here’s why: Losing a lot of blood can lead to a dangerous loss of blood pressure. That can limit how much blood, and therefore oxygen, reaches the brain and other vital organs. If deprived of enough oxygen, those tissues — and the patient — could die.

The body doesn’t have to spill most of its blood for this to happen. Losing about 2 liters (a half gallon) out of the 5 liters (1.3 gallons) or so in the body could be fatal. In fact, most deaths among army troops are due to excess blood loss — even if the inflicted wounds do not directly affect a vital organ, says Victor Convertino. A physiologist, he studies body functions at a research institute of the U.S. Army in Houston, Texas. He was not involved in this study.

Convertino thinks medics and others can save some lives if they can maintain adequate blood pressure — and thereby blood flow — to vital tissues until the victim reaches the hospital. (Vital tissues include the heart and brain.) Once there, blood transfusions can take over.

Blair Johnson may have found a way to achieve this. He is a physiologist at the University of Buffalo in New York. There, he focuses on developing effective ways to maintain blood pressure in the body after potentially catastrophic blood loss. He described a potential new first-aid approach…

Limitless Hydrogen Energy? Breakthrough Seen in Separating H from H2O

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Hydrogen is known to have the potential to become an important source of energy. And there’s an abundant supply of it, in our water, if we can just find a low-cost, efficient way of getting the oxygen in H2O to let go of it. The University of Houston (UH) has just announced that they may have just found it.

Splitting the hydrogen and oxygen in water is accomplished using a process called “water electrolysis” in which both the hydrogen and oxygen molecules separate into individual gasses via separate “evolution reactions.” Each evolution reaction is induced by an electrode in the presence of a catalyst.


Water can also be split using photocatalysis that uses solar power directly instead of electricity, but it’s less efficient since water only absorbs a small range of the light spectrum.

It’s been the lack of an efficient, low-cost catalyst for the oxygen molecules that’s been holding the full-scale extraction of hydrogen back. Up until now, oxygen catalysts have been based on scarce, expensive “noble” metals such as iridium, platinum, or ruthenium.

nobel metals

This is a problem that has been thwarting the full-scale commercial extraction of hydrogen for energy for some time, and UH isn’t the only entity searching for a replacement. Just last spring, the Canadian Department of Energy’s SLAC National Accelerator Laboratory and the University of Toronto announced the discovery of a new oxygen…

Researchers Discover How the Naked Mole Rat Can Survive 18 Minutes Without Oxygen

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The African naked mole rat (Heterocephalus glaber) is repulsive. It looks like an octogenarian sausage with buck teeth. Mostly found in the horn of Africa, these rodents live in warrens underground, serve a ruling queen, and spend most of their days gathering seeds and edible plants, or digging elaborate tunnels with their protruding front teeth and snouts. They live dozens and sometimes hundreds together and only the queen mates and bears young. In this way, they operate more like ants or bees than mammals.

Turns out these heinous, hairless monstrosities are a scientific marvel in quite a number of ways. For instance, they’re cold-blooded. These mole rats survive much, much longer than any other rodent, around 30 years or so. The naked mole rat doesn’t experience most kinds of pain and might even help us cure cancer. They don’t develop it. When researchers tried to sow cancer within them, they proved resistant.

Perhaps the most extraordinary thing about them is, they can survive for a long time without oxygen. Now, researchers have found out why. Turns out, they borrow a biochemical process from plants, according to a recent study published in the journal Science. Neuroscientist Thomas Park, a researcher from the University of Illinois-Chicago, told NPR that he and colleagues wanted to know how long the naked mole rat could last without oxygen.

Naked mole rat’s nose in a tunnel.

How naked mole rats survive in low oxygen environments has been a mystery, until now. By Bernard DuPont from France [CC BY-SA 2.0], via Wikimedia Commons

First they stuck four mole rats in a chamber which mimicked a low oxygen environment, one that would kill a mouse in about 15 minutes. Subjects became sluggish but were unfazed otherwise. They were in there for five hours without any trouble. This aspect of their physiology is important for their survival, as in the wild, they spend long period in tunnels where very little oxygen can be had….