Energy Production in The Body

Adenosine Triphosphate (ATP)

Energy Production in The BodyAdenosine Triphosphate is a chemical stored in the muscles that produces energy for muscle contraction to take place.  During rest more ATP is produced than needed and excess energy is transferred to creatine in your muscles. Increased blood flow by hyperemia help produce Creatine Phosphate. The body can store 80g-100g of ATP at one time. ATP is utilized for quick spurts of significantly demanding activities. During more strenuous workouts Adenosine Triphosphate is broken down at an accelerated rate and is depleted quickly.  

ATP + Creatine <–> ADP + Creatine Phosphate

  1.  Muscle activity breaks down ATP and Creatine as Adenosine Diphosphate(ADP) and Creatine Phosphate are created
  2. Creatine Phosphate (CP) aids to replenish Adenosine Diphosphate(ADP)
  3. ADP is then used to replenish Adenosine Triphosphate(ATP)
  4. ATP is used to convert Creatine to Creatine Phosphate

Naturally ATP and CP levels are replenished after a few minutes of rest after anaerobic activity.  CP level deplete within 15 second of physical activity.  The body stores four to six times more Creatine Phosphate than Adenosine Triphosphate, allowing for rapid ATP replenishment.

During aerobic activity the body uses other resources such as carbohydrates and fats from the glucose in your muscles, liver, and blood to make Adenosine Triphosphates.  The increased blood flow produced during muscle contraction optimizes energy usage for both aerobic and anaerobic activities.

Aerobic vs Anaerobic

At rest our body uses aerobic metabolism to fuel our body with energy. As we gradually start to exercise and slowly increase demand we can maintain use of aerobic energy production.

As intensity increases we get to a point where we start feeling fatigue and anaerobic metabolism begins.  At this point lactic acid begins to build up as the body’s energy expenditure increases.  Activities like weightlifting that require quick surges of energy can immediately provoke anaerobic metabolism.


Anaerobic conditioning stimulates your type II fast twitch muscle fibers for improvements in power, strength, and hypertrophy. Through anaerobic resistance training spikes in testosterone, growth hormones, and cortisol are prevalent. Anaerobic status occurs in high intense training with the absence of oxygen. As oxygen depletes lactic acid builds up causing muscle fatigue.

Lactic Acid

Lactic acid is produced as a byproduct of breaking down glycogen (glycolysis) without oxygen.  Mitochondria in the muscles absorb this lactic acid and use it as fuel. During high intensity training lactic acid can build up in the blood faster than the mitochondria can absorb it thus reaching it’s threshold.  This takes place after about 2 minutes of strenuous exercise and is signaled by feeling fatigued. As anaerobic endurance increases so does lactate threshold allowing for a delay in muscle fatigue and an improvement in performance.

2 Anaerobic System Energy Sources

Anaerobic endurance is fueled by levels of Adenosine Triphosphate(ATP), Creatine Phosphate(CP), and Glycogen.

  • The Phosphagen system uses ATP and CP for energy during the first 10-20 seconds of highly intensive activity and restore during a full recovery of 5-7 minutes.

  • The Glycolytic system kicks in after 10-20 seconds and provides energy through the breakdown of glycogen. This energy lasts for a few minutes of intense exercise with short rests.

Anaerobic exercises include weight training, agility training, intense interval training, and plyometrics. High anaerobic conditioning occurs in track and field sprinters, boxers, short distance swimmers, basketball players,fencers, and strength competitors.


Aerobic Energy Production

During strenuous aerobic exercise the muscles demand oxygen for metabolism.  Aerobic activity is supported by carbohydrates, lipids, and amino acids in circulating blood. During muscle contraction blood flow increases, surging oxygen and nutrients to these areas. This blood flow stimulates enzymes in the muscles to synthesize glycogen to glucose as a source of energy.  This is why long distance runners load carbohydrates or take glucose supplements before a race.

Aerobic Energy Usage

Aerobic exercise puts stress on the respiratory system increasing breathing frequency and volume.  This enhances overall blood flow helping muscles sustain during activity and providing them with more oxygen and nutrients. The development of type I slow twitch muscles improve aerobic endurance. Non-demanding movements for extended periods of time like long distance running or swimming are ideal.





Requires Oxygen

Does Not Require Oxygen

Macronutrient Use

Proteins and Fats


Energy Systems

  • Oxidative System
  • Glycolysis
  • Phosphagen System

  • Glycolysis: Phase 1

Cell Location



Macronutrients consist of Proteins, Fats, and Carbohydrates.  These macronutrients contains chemical energy which is converted into usable energy for our body.

Why an Empty Stomach?

Most pre workout supplements recommend use on an empty stomach…Why does this matter?

On a full stomach the body cannot fully absorb everything a pre workout has to offer because it’s working on digesting and absorbing from different sources. The more food digesting in your stomach before supplement consumption the less likely you will feel its full effect. 

During exercise blood flow increases by 65-75%. In order to meet this demand less blood is distributed to areas that need less oxygen like the stomach, kidney, liver, and intestines . Extra blood is then directed to the skin and muscles that are in immediate demand. The digestion process uses blood that we want focused at our muscles during exercise. Within 5 minutes of eating a meal blood flow is increased by 60%. By splitting up this focus our muscles don’t receive the optimal amount of oxygen and nutrients.

This does not mean you shouldn’t eat anything all day. It is important to maintain a proper diet and eat as needed. To maximize effectiveness of a stimulating supplement reserve a designated window of time for your body to fully digest before working out.  

On the extreme end some pre workouts like NO Xplode recommend use 2 hours after a meal.  Most pre workouts recommend not eating an hour before consumption. This is all based on estimates of how long it takes for food to be fully digested. Things like protein shakes that absorb quickly don’t require as long of a wait and are ideal.  

Meal Size vs Digestion Time

If you are eating a big meal I would recommend doing so 2 hours before. If it’s a light meal anywhere from an hour to 45 minutes will be enough. For the best protein synthesis with fast absorbing whey protein I recommend a protein shake 20 minutes before a pre workout.

Adrenal Fatigue

2 Most Important Adrenal Hormones

The adrenal glands fire as we create stress through exercise. Adrenal hormones are responsible for our fight-or-flight instinct and can be utilized during strength and conditioning. Adrenal glands promote secretion of hormones that provide benefits for strength training; like testosterone. When is comes to exercising the 2 most important hormones secreted from the adrenal glands are cortisol and catecholamines.


Cortisol is responsible for carbohydrate metabolism by converting amino acids into carbohydrates.  Cortisol helps store glycogen in the muscles and this glycogen provides energy for the muscles during contraction.  When the muscles run out of glycogen for energy they turn to protein.  This adrenal hormone increases production of enzymes that break down protein.  The greatest amount of cortisol is produced during anaerobic workouts where total volume is high and rest is short.


Even though Cortisol has essential properties, a large buildup is detrimental. Overtraining and high stress are two major factors that can cause build up of Cortisol.  Signs of overtraining can be a plateau or decrease in performance.  When a large amount of this hormone exists it causes suppression of immune system cells. This negative impact on the immune system leads to a decreased rate of muscle recovery and growth.

Cortisol buildup can result in a loss of protein because it causes an increased rate of protein breakdown. This takes away essential energy from the muscle and decreases strength.  If there is more testosterone and insulin hormones present than they will counter the negative effects produced by cortisol. Even though overtraining can be bad in the short run it can be beneficial in the long run once we decrease the load and allow our muscles to recover.


This hormone has a more physiological effect that contributes to better muscle performance.  Through central motor stimulation catecholamines increase focus, rate of muscle contraction, blood flow, and energy. Greater levels of catecholamine secretion occurs during conditioning sessions with a mixture of high volume , heavy resistance, and low rest.

Optimize Adrenal Hormone Production

Ideally your workout should change often so you do not burn out your adrenal gland and delay muscle recovery rates. Focus on larger muscle group exercises such as deadlifts, power cleans, squats, and bench press.  Our reps should consist of high volume with heavy weight.  Rest should consist of 10-60 seconds, reps could be anywhere from 8-15, sets should range from 2-3, and the weight should be your max for the coinciding repetition. The rest, reps and sets should vary to avoid cortisol buildup.


7 Important Deal Breakers

1) Serving size

2) Price

  • We all want to find the best deal and comparing pre workouts can be tricky.  In order to get the most out of your money you need to look at both serving size and price.  A good way to compare would be to look at the price per serving ratio.

Continue reading

Your Best Pre Workout

Not every supplement is guaranteed to work the way we desire.  Even if it does work at first it might not feel the same way consistently due to variables unrelated to the pre workout supplement itself.  In many cases the pre workout will have fluctuating levels of effectiveness between different people and different days.

3 Steps to Finding Your Pre Workout Supplement

Continue reading