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High Intensity Training vs. Low Intensity Training


Many might wonder the difference between high intensity and low intensity training. Which one is better? Should you do more of one than the other?It’s no surprise that high intensity interval training (HIIT) has gained popularity in a recent number of years.


Before I dive into the difference between the two styles of training, it’s important to understand some basics on the physiological response our bodies have to exercise and producing energy.


Our bodies use three different types of energy systems. These systems function by the production of adenosine triphosphate (ATP). ATP is what stores and transfers chemical energy within cells and is known as “molecular currency”.It is not only vital to important genetic processes like DNA replication and transcription, but is essential in producing energy for physical activity. Without ATP, muscular growth and activity would not be possible(Baechle,2008).


The three energy systems the body uses are the phosphagen system, glycolysis and the oxidative system.


The phosphagen system uses creatine phosphate and adenosine diphosphate (ADP) to create ATP. In layman’s terms, this reaction supplies ATP at a high rate, but cannot be maintained to supply energy for continuous exercise. This phase of energy production dominates n the first 5-6 seconds of maximal effort. Not only necessary during short term, high intensity workouts, phosphagen is always the first energy system to be used during the start of any activity regardless of intensity.


Glycolysis uses glucose to produce ATP instead of oxygen. Without oxygen, the only macronutrient that can be used to produce energy is carbohydrates. Hence, why proper carbohydrate regulation and nutrition have quite a meaningful impact. This energy system is used anywhere from 30 seconds to 3 minutes of activity and is the primary energy source for things like sprints, heavy lifting, interval training and explosive/plyometric movements.


The oxidative (aerobic) system requires oxygen to produce ATP. Because the rate of ATP production is much slower, this source of energy is used for longer duration and lower intensity activities. Aerobic exercise predominately uses carbohydrates and fats for energy. It will only use protein as a last resort in exercises lasting longer than 90 minutes in duration or during extreme starvation (Baechle, 2008). This is the primary energy source for things like long distance running, brisk walking, rowing and swimming.


High Intensity Training


High intensity training involves training at a maximal or submaximal effort for short bursts of time. High intensity interval training (HIIT) is a set period of work followed by a set period of rest.After a bit of background knowledge on how the body creates and uses energy, you can probably guess that interval training will predominately be anaerobic. This type of training is ideal for anyone looking to improve his or her strength, power or ability to tolerate higher intensity training for longer periods of time.


Low Intensity Training


Low intensity training is any training that is done for a prolonged period of time at a sustainable effort. All low intensity training is aerobic and is ideal for anyone looking to burn fat and improve cardiovascular efficiency.


Regardless of training style, any exercise is going to boost your mood, improve quality of sleep, lessen the risk for diseases relating to heart health and blood pressure, aid in weight loss, improve cognitive function, and much, much more. So, be sure to get up, move, and incorporate both high and low intensity training during your week!

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