Yes, this claim is accurate. Drinking too much water can lead to overhydration, also known as water intoxication or hyponatremia (1). This condition occurs when excessive water intake dilutes the sodium levels in your body, causing cells to swell. This swelling can affect your brain, leading to confusion, headaches, and in severe cases, seizures or coma (1). It can also impact your muscles and heart, causing cramps, elevated heart rate, and in extreme cases, low blood pressure (bradycardia).
It's important to balance water intake and be mindful of your body's needs, especially during intense physical activities or hot weather (1). Source: www.webmd.com