Heart racing on keto — normal or should I be worried?

Please don't panic — this is a known electrolyte effect, very common around days 3-7. Here's what's happening:

Your kidneys are excreting sodium at a much higher rate on keto (reduced insulin = less sodium retention). This drops blood volume slightly. Your heart compensates by beating faster to maintain blood pressure. It's the same mechanism that causes dizziness when standing up too quickly on keto.

Fix: Salt. Right now. Drink a tall glass of water with 1/2 teaspoon of salt, or have some bouillon or bone broth. In most cases the elevated heart rate calms down within 30-60 minutes of adequate sodium.

When to actually worry: If heart rate exceeds 120 bpm at rest, if you feel chest pain or pressure, if you're short of breath, or if symptoms don't improve after electrolytes. Those warrant a doctor's visit regardless of keto.

Had this exact experience on day 4. Ate some extra salt (literally just had a tablespoon of bouillon in hot water) and it was gone within 45 minutes. The connection between sodium and heart rate on keto is real and the fix is usually immediate. This was the moment I understood why electrolytes are non-negotiable, not optional.

To add the physiology: the heart needs adequate electrolytes (especially sodium, potassium, and magnesium) for normal electrical conduction. On keto you're losing all three faster than normal. The racing/palpitations sensation is the heart's electrical system slightly desynchronized from electrolyte imbalance — genuinely benign in this context but a clear signal to address your electrolytes immediately.

I made a cup of bouillon immediately after reading this. 30 minutes later my heart rate is back to normal. Incredible. Thank you — genuinely scared me before this thread.

This is the best argument for why keto beginners need to have electrolytes ready before day one. Not after symptoms appear — before. Glad you're okay.