When winter arrives, many people see a hot shower as the most relaxing moment of the day. However, doctors at Maharaj Nakhon Ratchasima Hospital (Thailand) warn that this habit can be dangerous if done incorrectly.

According to Khaosod (Thailand), Dr. Jed Bunyawongsaweelach, Deputy Director of the hospital and Director of Primary Care, explained that while many believe warm showers are completely safe, the truth is that “the way you shower directly affects your heart.” In cold weather, blood vessels constrict more strongly, and the heart reacts more sensitively to sudden temperature changes. Even small mistakes can cause rapid heartbeat, a spike in blood pressure, dizziness, or even fainting.

Dr. Jed highlights five dangerous habits that everyone should avoid:

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1. Using extremely hot water immediately

When your cold body suddenly touches very hot water, blood vessels expand too quickly, forcing the heart to work harder to stabilize temperature. This can cause dizziness or loss of balance.
Best tip: Start with warm water, then gradually increase the heat.

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2. Showering right after intense exercise

After working out, your heart rate is already high. Hot water will dilate your blood vessels further, putting even more stress on your heart. This may trigger palpitations or lightheadedness.
Best tip: Rest 15–20 minutes after exercising before showering.

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3. Showering on an empty stomach

When you’re hungry, blood sugar is low, and less blood flows to the brain. Hot water dilates blood vessels, and if your heart cannot keep up, dizziness or fainting can occur.
Best tip: Eat a small snack—like a few bites of whole-grain bread—before showering.

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4. Staying in a hot shower for too long

Spending more than 15–20 minutes in hot water keeps your blood vessels expanded for too long, making the heart pump harder. This can cause fatigue, palpitations, and reduced blood flow to the brain.
Best tip: Limit hot showers to 10–15 minutes.

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5. Showering immediately after waking up

Right after waking, blood pressure is low and heart activity is slow. Exposure to warm water too quickly can shock the system, raising the risk of irregular heartbeat, dizziness, or falls.
Best tip: Sit up slowly, move around gently, and wait 5–10 minutes before showering.

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Dr. Jed emphasizes that in cold weather, the heart and circulatory system react strongly to temperature changes. Adjusting your shower habits—avoiding overly hot water, not showering when hungry or after intense activity, and limiting shower time—can significantly reduce risks such as dizziness, palpitations, and cardiovascular complications. Those with high blood pressure or heart disease should be even more cautious.