How the human body reacts while running

Published June 5, 2017
Aerospace and Operational Physiology

PETERSON AIR FORCE BASE, Colo. — -- Do you ever wonder how your body physiologically responds to an exercise such as running? In order for our muscles, cells and organs to work properly our blood must first carry oxygen and nutrients to them. During intense physical activity, the body’s blood flows to our larger muscle groups, which are generally working the hardest.

The largest muscle in our body, the gluteus maximus, is heavily used while running but rarely used while walking according to the New York Times. Our muscles must have glucose and oxygen to create a molecule called adenosine triphosphate, or ATP, which is our body’s energy currency.

The heart starts beating faster in response to the increased demand for oxygen. Frequent exercise increases the amount of blood it can pump with each beat. This is one reason why those who engage in regular exercise have been found to have lower heart rates than people who are sedentary.

Were humans built to run?

According to conventional wisdom, running longer distances adds extra strain to our bodies, especially our joints. However, according to Christopher McDougall, author of “Born to Run”, running isn’t inherently risky. Mr. McDougall argues that overzealous training combined with poor running form and high-tech shoes are the main sources of injuries.

Running in high tech shoes can change the bio-mechanics of running which increases the chance of injury. Scientific evidence points to the notion that humans evolved to be runners.

Humans have a great cooling system with many sweat glands but little body hair which allows us to stay cool at higher speeds and longer distances by sweating unlike some other animals that pant and would overheat.

When it comes to distances, humans can outrun almost any animal. Every year in the small Welsh town of Llanwrtyd Wells, this notion is put to the test at the annual Man Vs Horse Marathon which began in June, 1980. Each year the races have been close, with the horse winning sometimes only by a few seconds. However, in 2014 a man won and proved that humans can outlast a horse over the course of 26.2 miles. Huw Lobb won in two hours and five minutes, beating the fastest horse by two minutes.

Complications of distance running

If you’re planning on running a marathon anytime soon, keep in mind there is no substitution for preparation.

The average marathon runner will take between 30,000 and 50,000 steps, each of which puts a stress three to four times your body weight on your knees, hips, lower back and ankles. Other factors that could lead to injury include: illness during the weeks prior to running, medication and participation in other sports.

Another risk while running for a great amount of time is hyperthermia, a condition of dangerously overheating. High temperature and levels of humidity can make heat loss more difficult and the body can overheat.
Dehydration can also lead to a lack of heat transfer from the muscles to the skin, worsening the situation. In 2001, a 22 year old man collapsed within 300 yards of finishing the Chicago Marathon and later died with a 107° Fahrenheit internal temperature while the outside air temperature was only in the 50s.

Some key elements to reduce the risk of injury while running are: eating a well-balanced diet, getting an adequate amount of sleep, keeping life stresses to a minimum and training properly for distance running.

Running great distances is both a testament to the endurance of the human body and one of the most popular forms of exercise.

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