Homeostasis is the integration of body systems that is able to maintain a constant unchanging internal environment. Typically homeostasis is what we experience at rest. Exercise places stress on the body which disturbs homeostasis. When exercising the body has mechanisms that can maintain a “steady state” which help to maintain a safe internal environment. All homeostatic mechanisms use negative feedback to maintain a constant unchanging environment to maintain a set-point which the body considers normal.
In order to maintain a safe internal environment, the body has self-regulating control systems. These control systems are made up of receptors, an integrating centre and an effector that corrects any undesirable imbalances within the body to return it to this set-point.
The effector detects a stimulus or change within the body’s system. These then send signals (negative feedback) to the integrating centre. The integrating centre interprets this signal and compares this to the set-point and sends a stimulus to an effector. The effector corrects these changes in order to maintain homeostasis. If a change is made and the receptors still detect an imbalance the cycle will repeat itself until a stable state (acceptable) is achieved. For example when you exercise you sweat. This is an example of how control systems at work within exercise:
There are two sets of thermoreceptors: receptors in the hypothalamus which monitors the temperature of the blood as it passes through the brain (core temperature) and receptors on the skin which detect the external temperature. (McArdle, Katch and Katch, 2010)
The hypothalamus itself is also the integrating centre which compares the detected temperature with the desired temperature. If this detected temperature is outside the safe bandwidth of acceptable body temperature (37o ±0.5o) it sends a signal to an effector to correct the change. The bigger the change detected the bigger the response.
So what? Where can I see Homeostasis in action?
The cardiovascular system is working harder to supply the tissues with more blood which contain oxygen (O2). Breathing rate is increased to possibly keep up with increased demand. I’m red in the face because I’m hot and by sweating I am trying to cool down my body temperature. I’m drained of energy because I know from nutrition studies the muscles have limited stores of glycogen that supply Adenosine triphosphate (ATP) in order to contract my muscles.
I also have observed different responses when training on a cold day or a hot day. On a cold day I shiver before training until I get warmed up. On a hot day I sweat more than on a cold day. In a humid day I feel almost suffocated as I am unable to cool down just by sweating – I normally need to pour cold water on my face and the back of my neck. My body is trying it’s hardest to maintain a stable internal temperature.
McArdle, Katch and Katch (2010) explain the stable temperature of a human body is approximately between 36-38o. In a cold environment we experience heat loss. Most people shiver to keep warm. In a hot environment most people become too hot and tend to sweat.
When thinking about my training routine, why do I have to warm up just so I can get hot and start sweating only to have to warm down?
I learned in exercise prescription that a warm up and warm down is essential as this helps the body prepare for exercise and help it get back to a resting state. I was always told that warming down prevented the likelihood of getting a chill and possibly the flu. I could assume now that warming down could be the gradual internal return to homeostasis from a steady state during exercise. I have always warmed up the football team I coach and explained that we do this to get ready for more intense drills during practice and so we are ready for game performance. I get them to warm down in order to reduce muscle soreness and avoid chills. So what else ?
Obviously many systems change in order to for us to perform exercise. So what happens to our cardiovascular, respiratory and cooling systems when we perform more work such as exercise and performance in sport?
Other areas I think I can see homeostasis at work is within nutrition. When trying to gain or lose weight the body has a set point in which it tries to maintain its current weight. The body doesn’t like change and if we try to adjust our intakes it tries to correct any nutritional imbalances or changes to diet by either increasing appetite or storing excess caloric intakes as fat. This is why we must gradually reduce or increase caloric intake to get the desired result.
From exercise prescription I know you need to apply the principle of overload to make adaptations. I know that in order to get fitter or improve performance you must do more work. If you do more work you increase the disturbance to homeostasis.
How do other systems work together to maintain a steady state when exercising?
So if you want to get fitter or improve your performance how do these systems adapt to an increase in work and how does this increase performance? What modes cause what adaptations?
During a boxing training session I can feel my heart rate increasing, my breathing becomes deeper and more frequent, my skin becomes flushed, I sweat and my muscles start to become fatigued. At the end of a training session I’m thirsty and thoroughly tired.
These symptoms or otherwise known as responses to exercise are examples of systems at work to maintain this “steady state” during exercise in order to function effectively for performance.
So what are these systems?
The cardiovascular system is working harder to supply the tissues with more blood which contain oxygen (O2). Breathing rate is increased to possibly keep up with increased demand. I’m red in the face because I’m hot and by sweating I am trying to cool down my body temperature. I’m drained of energy because I know from nutrition studies the muscles have limited stores of glycogen that supply Adenosine triphosphate (ATP) in order to contract my muscles.
I also have observed different responses when training on a cold day or a hot day. On a cold day I shiver before training until I get warmed up. On a hot day I sweat more than on a cold day. In a humid day I feel almost suffocated as I am unable to cool down just by sweating – I normally need to pour cold water on my face and the back of my neck. My body is trying it’s hardest to maintain a stable internal temperature.
McArdle, Katch and Katch (2010) explain the stable temperature of a human body is approximately between 36-38o. In a cold environment we experience heat loss. Most people shiver to keep warm. In a hot environment most people become too hot and tend to sweat.
When thinking about my training routine, why do I have to warm up just so I can get hot and start sweating only to have to warm down?
I learned in exercise prescription that a warm up and warm down is essential as this helps the body prepare for exercise and help it get back to a resting state. I was always told that warming down prevented the likelihood of getting a chill and possibly the flu. I could assume now that warming down could be the gradual internal return to homeostasis from a steady state during exercise. I have always warmed up the football team I coach and explained that we do this to get ready for more intense drills during practice and so we are ready for game performance. I get them to warm down in order to reduce muscle soreness and avoid chills. So what else ?
Obviously many systems change in order to for us to perform exercise. So what happens to our cardiovascular, respiratory and cooling systems when we perform more work such as exercise and performance in sport?
Other areas I think I can see homeostasis at work is within nutrition. When trying to gain or lose weight the body has a set point in which it tries to maintain its current weight. The body doesn’t like change and if we try to adjust our intakes it tries to correct any nutritional imbalances or changes to diet by either increasing appetite or storing excess caloric intakes as fat. This is why we must gradually reduce or increase caloric intake to get the desired result.
From exercise prescription I know you need to apply the principle of overload to make adaptations. I know that in order to get fitter or improve performance you must do more work. If you do more work you increase the disturbance to homeostasis.
What do I not understand?
How is sweat created and why?How do other systems work together to maintain a steady state when exercising?
So if you want to get fitter or improve your performance how do these systems adapt to an increase in work and how does this increase performance? What modes cause what adaptations?
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