09 Oct What is Metabolic Flexibility and Why Does it Matter?
You’ve probably heard of burning fats and sugars and may even have heard the term metabolic flexibility, but what does it mean and why does it matter for your fitness and health?
What is it?
Metabolic flexibility is the ability to switch between fuel sources - dietary and stored fat, glucose (sugar) and glycogen (sugar stores). Being metabolically flexible means that you are able to switch your metabolism to meet your body’s physical demands. Getting “hangry” is a sign that you aren’t tapping into your stores when you need to. High caloric consumption with low energy expenditure is the culprit for most people with metabolic inflexibility, i.e. low or excess levels of glucose or fat metabolites.
Why does it matter?
Exercise training can improve metabolic flexibility so that muscle and fat tissue are better at communicating with one another to meet energy demands. Engaging in both aerobic and endurance exercise trains metabolic flexibility, which allows the body to switch between fat-burning and glucose production on demand. On the other hand, lack of activity can lead to excess levels of glucose and fat metabolites in the blood, which causes metabolic inflexibility as muscles are slower to take up and burn these fuels as an energy source.
How do you measure it?
The two key biomarkers that influence metabolic flexibility are glucose and beta-hydroxybutyric acid (BHB). Glucose is a simple carbohydrate. It is your body and brain's key source of energy. High glucose levels usually mean there is an impairment in your body’s capacity to use dietary sugar. Low glucose usually means your carbohydrate intake is insufficient for your needs or that your body is slow to produce glucose after fasting. BHB is a ketone, a product of fat metabolism. BHB can be used as an energy source when glucose levels are low. High fasting BHB levels indicate that your body is metabolizing fat stores but not using BHB as an energy source, whereas low fasting BHB levels indicate that your body is not burning fat stores.
What type of training improves sugar usage?
High intensity exercise increases the use of glucose to supply fast twitch muscle fibers (used for sprinting or powerful bursts of energy).
What type of training improves fat usage?
Endurance exercise increases the use of fats and ketones to fuel slow twitch muscle fibers (used for distance running, swimming, cycling) and other organs such as the heart, brain and liver. Exercising in a fasted state can also help train the body to use fats for energy.
How can I get tested for metabolic flexibility?
myFitnessFx tests uses blood marker analysis, to show what’s happening in the body, at the molecular level, in response to exercise. The product looks at five primary areas of fitness: metabolic flexibility, training and recovery, mitochondrial function, athletic benchmarking and underlying health. myFitnessFx also provides personalized recommendations for improving fitness, correcting nutritional imbalances and addressing any underlying health issues.
Learn more about myFitnessFx Precision Fitness Testing.