Hot tubs are designed for relaxation, muscle relief, and stress reduction—but they are not safe places to fall asleep. While soaking in warm water may feel soothing and even make you drowsy, sleeping in a hot tub can pose serious, potentially life-threatening risks. Understanding these dangers is essential for protecting your health and safety.

Why Hot Tubs Make You Sleepy

Warm water causes blood vessels to dilate, lowering blood pressure and promoting muscle relaxation. This effect can create a sense of calm and sleepiness, especially after a long day. Additionally, the buoyancy of water reduces physical tension, which can further encourage drowsiness.

However, the same physiological responses that promote relaxation can also impair awareness and reaction time—making it dangerous to remain in a hot tub without full alertness.

Risk of Overheating and Hyperthermia

One of the most serious dangers of sleeping in a hot tub is overheating. Hot tubs are typically maintained at temperatures between 100°F and 104°F (38°C to 40°C). Prolonged exposure to this level of heat can raise core body temperature to unsafe levels, leading to hyperthermia.

Symptoms of overheating include:

• Dizziness or lightheadedness

• Nausea or vomiting

• Confusion or disorientation

• Rapid heartbeat

• Fainting or loss of consciousness

Once someone falls asleep, they may not recognize these warning signs, increasing the risk of severe complications.

Increased Risk of Drowning

Even though hot tubs are relatively shallow, they still pose a drowning risk—especially if someone becomes unconscious. Heat-induced hypotension (low blood pressure), dehydration, alcohol use, or medications can cause a person to pass out. If this happens while asleep or drowsy, the risk of slipping underwater and drowning rises significantly.

Unlike pools, hot tubs have limited space, which can make it difficult to reposition or escape if consciousness is impaired.

Dehydration and Electrolyte Imbalance

Soaking in hot water causes the body to sweat, even though the water may mask it. Extended exposure can lead to dehydration and electrolyte imbalances, which may contribute to muscle cramps, headaches, dizziness, and irregular heart rhythms.

Sleeping through prolonged heat exposure increases the likelihood of these effects going unnoticed until they become severe.

Cardiovascular Strain

Hot tubs place additional strain on the cardiovascular system. Heat causes blood vessels to dilate, lowering blood pressure and increasing heart rate. For individuals with heart disease, hypertension, arrhythmias, or autonomic dysfunction, this can be particularly dangerous.

Sudden changes in posture—such as standing up quickly after prolonged soaking—can lead to fainting or falls due to orthostatic hypotension.

Interaction With Alcohol and Medications

Alcohol significantly increases the danger of sleeping in a hot tub. It impairs judgment, increases sedation, and worsens dehydration. Many medications—including sedatives, sleep aids, opioids, muscle relaxants, and certain antidepressants—can further suppress alertness and blunt the body’s response to overheating.

The combination of heat, alcohol, and sedating medications dramatically increases the risk of loss of consciousness and accidental drowning.

Risk for Children and Older Adults

Children and older adults are especially vulnerable to the dangers of hot tub sleeping. Children overheat more quickly and may not recognize or communicate symptoms effectively. Older adults may have impaired temperature regulation, balance issues, or underlying medical conditions that increase risk.

For these populations, even short periods of unsupervised soaking can be hazardous.

Sleep Does Not Equal Recovery in a Hot Tub

Some people mistakenly believe that dozing in a hot tub provides restorative rest. In reality, sleep in a hot tub is not safe or beneficial. True restorative sleep requires a drop in core body temperature—something that cannot occur in hot water. Instead of improving sleep quality, overheating can disrupt normal sleep physiology and worsen fatigue.

Safe Hot Tub Use Guidelines

To reduce risk and enjoy hot tubs safely:

• Limit soaking time to 15–20 minutes

• Keep water temperature at or below 104°F (40°C)

• Stay hydrated before and after soaking

• Avoid alcohol and sedating medications

• Exit the tub immediately if feeling dizzy or lightheaded

• Never use a hot tub alone for extended periods

• Do not allow children to use hot tubs unsupervised

• Always leave the tub before feeling sleepy

If you notice frequent drowsiness during hot tub use, it may be a sign of overheating or low blood pressure and should not be ignored.

The Bottom Line

Hot tubs are meant for short-term relaxation—not sleep. Falling asleep in a hot tub can lead to overheating, dehydration, cardiovascular strain, and increased risk of drowning. These dangers can escalate quickly and silently, especially when combined with alcohol, medications, or underlying health conditions.

Enjoy hot tubs mindfully and safely, and remember: when it comes to sleep, the safest place to rest is a cool, quiet bed—not a hot tub.

If you or someone you know struggles with sleep, please click the orange button below to take a free online sleep test and talk with one of our sleep health professionals.