Body Mechanics: Exercise Intensity

intense-workoutHello and welcome to another edition of Body Mechanics. Today I thought we would discuss intensity and how it affects our workouts. Not every workout is created equal and not every workout is intended for everyone.

I understand that when we are first starting out, the intensity of our workouts must be reduced to maximize both physical and cognitive adaptations. Both changes must occur, but as Trainers/Coaches our primary job should be to ensure that both are occurring optimally. The brain adapts by improving neuromuscular connections between the brain and the muscle, which improves coordination, sensory perception and correct muscle sequencing. The body adapts by increasing the density of the torn muscle fibers that have been torn in the process. The muscles being used also require more blood to sustain the required movement, the heart increases blood flow to allow proper circulation to required tissues and cells. The body has its own way regulating the way it functions; homeostasis.

The term homeostasis literally means constant and stable in Latin, which makes it simple to explain as our body’s very own thermostat. The process thereby known as homeostasis has many different regulatory responses that the body induces. The human body’s normal temperature is 37 degrees Celsius, our body has many organs such as the kidneys, heart and muscles that help in maintaining this temperature. However the most important component of this process is the hypothalamus. This gland is found at the stem of the brain and plays the biggest role as it integrates the endocrine system with the nervous system. It is important to know that the endocrine system is comprised of many glands that regulate the secretion of hormones, in turn regulating our bodily functions.

As these chemical hormones are released our body reacts by either releasing other hormones or adapting to the hormone. As we exercise our breathing becomes increasingly important and if the oxygen demands are not met our body cannot sustain the activity. Oxygen must be taken in and directed to the appropriate tissues immediately. We know that our muscles require blood flow (oxygen) in order to sustain the movement. Our body’s response to this is through increased heart rate, blood pressure and vasodilation. Our sweat glands may also increase in size which will more adequately cool the body as the intensity of the workouts increases. The function between the autonomic nervous system and the endocrine system occurs involuntary, the greatest multi-task of all time.

armsgirlSo how does this all tie in to what we are discussing and workout intensity? Homeostasis is also the body’s way of functioning optimally or efficiently. What do we know about the word efficient? “Achieving maximum productivity with minimum wasted effort or expense.” So for lack of a better word lazy, our body is extremely lazy. It will only expend the amount of energy required to sustain the movement and no more. Our body adapts and learns very quickly and because of this we must constantly try new exercise or progress ones that have become too easy for us. Homeostasis occurs on all fronts, it improves cardiac response, proprioception and muscle strength. It can even anticipate what we are doing, for instance some people begin to sweat before exercise has even begun, this is the body’s way of saying relax I got this, you’ll be just fine.

Homeostasis also plays a role in caloric expenditure, the food we eat is our energy or our fuel. It takes a certain amount calories in order for our body to function, the amount of calories for us to get through the day is known as the basal metabolic rate (BMR). Every breath you take is using energy, the more muscle you have the more calories required to maintain at rest. All of these calories burned at rest is the BMR at work, and we all have a slightly different BMR.

Oxygen uptake is the ability of the body to take in and use oxygen, the greater the uptake the better shape the person is in. Even if we were to do low intensity exercise we must initially turn to our anaerobic means of energy production, which creates a “debt”. Eventually we will reach steady state and our body will begin to function aerobically. This debt is also known as excessive post-exercise oxygen consumption or EPOC. This oxygen debt must be paid in full immediately post exercise, however just like in real life all debt is not bad. This debt is great for our BMR which we discussed a little bit earlier. Our body must now go into overdrive in order to replenish the oxygen debt to resting values. We must now restore homeostasis and have the body return to functioning optimally.

cyj-tired-athlete-photo-e1328729863667The EPOC may only take a few minutes from what we can see physically. However the processes that occur in our body post exercise are of the utmost importance and may last for several hours. Calories burned during exercise are important but the ones that count the most are the ones burnt after our workouts. Increased intensity will decrease the duration of the activity substantially but it will also increase the amount of calories burned post exercise through EPOC. So work as hard as you can for the amount of time that you are working out and remember that the greatest adaptations occur at the cellular level, which cannot be measured by the eye.

Happy Lifting!

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1 comment for “Body Mechanics: Exercise Intensity

  1. May 15, 2013 at 6:36 am

    Great stuff Carlos. The human body is a complex one and one that is well worth learning about. Thanks for sharing the information and keep these coming!

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