The ketogenic diet is defined by very low carbohydrate intake, moderate protein, and high consumption of dietary fats. This reduction causes the body to shift its primary fuel source from glucose to fat, entering a metabolic state called ketosis. Heart palpitations are the sensation of a racing, pounding, or fluttering heart. This irregular heart rhythm is a frequently reported side effect for some people during the initial dietary transition.
The Link Between Ketosis and Palpitations
The occurrence of palpitations often aligns with the initial adaptation phase, sometimes referred to as the “keto flu,” which typically lasts for the first few weeks of the diet. When carbohydrate intake is severely restricted, the body rapidly depletes its stored glucose reserves, known as glycogen. Glycogen is stored in the liver and muscles, and each gram is bound to approximately three grams of water. As the body uses up these stores, the associated water is released and flushed out through the kidneys. This rapid expulsion leads to a significant diuretic effect and a quick reduction in fluid volume, triggering the subsequent loss of crucial minerals from the body.
Electrolyte Imbalance and Cardiac Rhythm
The primary cause of keto-related palpitations is the imbalance of electrolytes, which are minerals that carry an electric charge. When carbohydrate intake drops, insulin levels decrease, signaling the kidneys to excrete more sodium and water. This process, called natriuresis of fasting, results in the loss of sodium, potassium, and magnesium. These three electrolytes are fundamental for maintaining the heart’s steady rhythm.
The heart muscle contracts through a precise sequence of electrical impulses, known as the action potential. Sodium and potassium are the main ions that move across the cell membranes to generate these electrical signals, relying on the sodium-potassium pump to maintain concentration gradients. Magnesium acts as a cofactor for this pump and helps regulate calcium channels, stabilizing the electrical activity of the heart muscle cells. When these electrolytes are deficient, the delicate electrical timing of the heart can be disrupted, resulting in an irregular heartbeat or the sensation of palpitations. Low potassium levels (hypokalemia) are particularly linked to an increased risk of ventricular arrhythmias.
Strategies for Managing Palpitations
The most direct way to mitigate keto-related palpitations is by proactively addressing the fluid and mineral losses that occur during the dietary shift. Increasing water intake is necessary to combat dehydration, which exacerbates the mineral loss and can lead to a reduced blood volume that strains the heart. Adequate hydration is essential to support the body’s new metabolic state.
To replenish sodium, individuals can increase their intake of salt through simple methods like adding extra salt to food or drinking salted water or bone broth. It is recommended that people on a ketogenic diet consume between 3,000 and 5,000 milligrams of sodium per day, especially in the beginning. Potassium is equally important for muscle and nerve function, and sources like avocados, spinach, and mushrooms are excellent keto-friendly options.
Magnesium is involved in over 300 biochemical reactions, and many people are already deficient before starting the diet. Foods such as leafy greens and nuts can boost magnesium, and supplementation may be necessary to ensure an intake of up to 400 milligrams daily. By consistently supporting the body with these minerals, the electrical stability of the heart can be maintained, and the transient side effects of the adaptation phase can be significantly reduced.
When to Seek Medical Attention
While most keto-related palpitations are benign and temporary, they should not be dismissed if they persist or worsen. If the fluttering sensation is accompanied by chest pain, immediate medical consultation is warranted. Severe shortness of breath or difficulty breathing alongside palpitations is a signal to seek professional help without delay. Other serious warning signs include feeling dizzy, lightheaded, or fainting, as these may indicate a significant underlying cardiac issue or severe electrolyte disturbance.