Is it good to run on an empty stomach in the evening?
Apr 28, 2022
Source: Cainiu Health
Dr. Pan Yongyuan
Introduction
Fasting blood glucose levels are low; glucose is the primary energy source for the brain. Fasting running further reduces blood glucose, leading to insufficient energy supply to the brain and potentially causing hypoglycemic symptoms such as dizziness, limb weakness, and syncope. Free fatty acids in the bloodstream serve as an energy source for cardiac and other skeletal muscles; however, the heart muscle utilizes fatty acids inefficiently. Excess free fatty acids may trigger various arrhythmias—and even sudden cardiac death.
Running is an exceptionally healthy aerobic exercise. Consistently running daily accelerates systemic blood circulation, enhances immune function, and reduces the risk of developing various diseases. Running also effectively strengthens mental resilience and aids in weight loss and body shaping. So, is it advisable to run on an empty stomach in the evening?
Is Evening Fasting Running Advisable?
Fasting blood glucose levels are already low; since glucose serves as the primary energy source for the brain, fasting running further depletes blood glucose, potentially depriving the brain of sufficient energy and leading to symptoms such as dizziness, generalized weakness, and syncope—classic manifestations of hypoglycemia. Free fatty acids circulating in the blood serve as an energy source for cardiac and other skeletal muscles; however, the heart’s efficiency in utilizing fatty acids is relatively low. Excessively elevated free fatty acid levels may trigger various arrhythmias—and, in rare cases, even sudden cardiac death. Although such incidents are uncommon, historical studies have documented cases of sudden death among several well-known middle-aged and elderly recreational joggers who exercised while fasting. Furthermore, under conditions of insufficient carbohydrate availability, some fatty acids undergo incomplete oxidation, resulting in increased ketone body production. Excessive accumulation of ketone bodies may precipitate metabolic acidosis. Additionally, fasting exercise often induces hunger pangs and may cause abdominal pain, impairing normal digestive function. Therefore, it is generally recommended to avoid exercising on an empty stomach.
If you are accustomed to fasting exercise, consider consuming a small amount of carbohydrates prior to your workout—for instance, a serving of fruit juice or honey. This precaution is especially important for middle-aged and older adults, many of whom suffer from hypertension or diabetes. Due to age-related physiological changes and reduced capacity to metabolize fatty acids efficiently compared with younger individuals, older adults should particularly avoid fasting exercise.
Moreover, running immediately after a large meal is also not advisable; instead, wait at least one hour after eating before beginning your run. We hope this information proves helpful!
