Understanding Blood Sugar and Insulin Regulation in CrossFit Workouts


The human body is complex. It comprises numerous organs, body parts, structures, and individual cells which are in constant coordination with each other. Each of the systems strives to maintain homeostasis or an optimal range despite the varying external and internal signals. Blood sugar also referred to as glucose because it is one of the examples of constant exquisite coordination which produces lots of things from basic physiologic functions all the way to elite athletic performance.

CrossFit Workouts

Every cell within the human body uses glucose to generate energy which powers muscle contraction during CrossFit workouts. The major consumers of glucose include the brain, the muscle, liver, and adipose tissue. For instance, the brain uses approximately 120 grams of glucose daily which accounts for about 60% of the total usage by the body.

The protein hormone known as insulin is responsible for regulating glucose homeostasis. Whenever there is an elevated blood glucose level, insulin is secreted from the pancreas and injected into the blood. This particularly comes when you take a carbohydrate meal or fat and protein only meal.

Increased insulin gets detected by the insulin receptors on the surface of the cell and this signals for the absorption of glucose from the blood. This, in turn, increases the internal cell concentration of glucose.

CrossFit Workouts

Insulin is a powerful central regulator of metabolism, and it's presence signals energy sufficiency which drives energy storage in the form of fatty acids or glycogen. It can also usher in energy consuming processes which include cell division. The adipose tissue, liver, and skeletal muscles are the main targets of insulin action.

Even though the glucose uptake by the brain is not controlled by insulin, research indicates that insulin affects the control of energy and glucose homeostasis in the brain.

Day-to-Day Examples of Control

After a full night’s sleep, your glucose levels dip below the day’s average which is usually 70 to 100 mg/dL. When you take your first meal, glucose levels spikes and insulin comes into action to suppress it to below 140 mg/dL. This cycle repeats itself day in day out.

CrossFit Workouts

Where the body system cannot be able to lower glucose, it is indicative of glucose homeostasis regulating the problem. During a CrossFit exercise, the body muscles utilize existing supply of energy which lasts for about 10 seconds. After the depletion of the existing fuel source, the body shifts to glucose and glycogen along the glycolytic pathway.

The glycolytic pathway under maximum body training lasts for about two minutes and paves the way for glycolysis to provide energy. For longer duration activities and workouts, fats are the predominant fuel source.

During exercise, blood glucose levels rise because the liver breaks down its glycogen stores which are about 100 grams or create glucose from other sources through the process of gluconeogenesis and releases it into the blood. This elevated blood glucose levels results in a release of insulin which helps to push the glucose into the muscle cells.

CrossFit Workouts

Through exercises, the muscle cells are triggered to take up blood glucose by another mechanism which doesn’t require the help of insulin. One of the top benefits of CrossFit training is that it enhances your insulin sensitivity through this mechanism because it allows for insulin levels to remain low while blood sugar increases.

During the post-exercise recovery period, the blood glucose levels fall to the normal levels as muscle cells replenish glycogen stores back to the levels before the exercise.


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