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Why does using a sauna lead to deep sleep? The effects of saunas and their relationship with sleep.

2025.06.27

Why can you sleep deeply after using a sauna? The effects of saunas and their relationship with sleep

The Invitation to Deep Sleep Brought by Saunas

In today’s stressful and busy society, achieving quality sleep is a major challenge for many people. In this context, the sauna is gaining attention. The relaxation effect provided by saunas is said to improve sleep quality, going beyond mere temporary comfort. This is mainly due to its effects on body temperature regulation and the autonomic nervous system.

When you enter a sauna, your body temperature temporarily rises. After this, it naturally begins to decrease. This process creates an ideal state before bedtime, inducing natural drowsiness. Additionally, by affecting the autonomic nervous system, it balances the sympathetic and parasympathetic nerves, leading to a relaxed state both physically and mentally.

Furthermore, many studies report that over 75% of people feel an improvement in sleep after using a sauna. Against this backdrop, “Sauna and Deep Sleep” is now spreading as a new health method. Here, we will explore the mechanisms and effects in detail.

The Relationship Between Saunas and Improved Sleep Quality

The relaxation effect obtained from using a sauna is said to greatly enhance sleep quality. Specifically, the process of warming the body in the sauna and then cooling it down regulates the autonomic nervous system and suppresses stress responses. This process balances the sympathetic and parasympathetic nerves, creating a state that is easy to relax into, which is a crucial factor for sound sleep.

Changes in Core and Peripheral Body Temperature

Saunas affect core and peripheral body temperatures, inducing natural drowsiness. The temporary rise in core body temperature due to the sauna, followed by a gradual decrease, naturally transitions the body into a relaxation mode. This series of changes creates the ideal condition before bedtime, leading to comfortable sleep as a result.

The “Golden 90 Minutes” of Deep Sleep

Particularly noteworthy is the deep sleep in the initial stage, known as the “Golden 90 Minutes.” This term is derived from the deep non-REM sleep achieved in the first 90 minutes. This deep sleep, promoted by the sauna, stabilizes the subsequent lighter sleep, providing quality rest throughout the night.

The Fatigue Recovery Effect of Sauna Use

Saunas are also expected to promote blood circulation. Improving blood flow throughout the body increases oxygen supply and activates metabolism. Additionally, the moderate fatigue resulting from this process is felt as a pleasant languor, which also prepares the body for quality sleep.

Psychological Stress Reduction Through Alternating Baths

In saunas, switching from a high-temperature environment to a cold bath (alternating baths) stimulates the autonomic nervous system. This activity can also lower cortisol levels, a stress hormone. As a result, it is said that you can refresh both body and mind, making it easier to fall asleep free from anxiety and tension.

Scientific Research on Saunas and Sleep Improvement

In 2019, interesting research results were reported. According to this, about 75% of subjects felt a “clear improvement in sleep after using the sauna.” This data indicates that many people are actually benefiting from it. However, there are individual differences, and in some cases, it can have the opposite effect, so caution is needed.

How to Use at the Optimal Timing

To maximize efficiency, it is recommended to use the sauna within a few hours before bedtime (1 to 2 hours as a guideline). At this timing, the natural decrease in body temperature can be achieved, leading to smooth sleep. Additionally, consider the differences in cooling processes such as cold baths at each facility and your own tolerance.

Conclusion: Health Benefits from Regular Sauna Use

As we have seen, understanding “Why can you sleep deeply after using a sauna” reveals common points such as autonomic nervous system regulation, metabolism promotion, and psychological care. However, enjoying it without overdoing it is the top priority, and it’s important to set a pace that suits you.

Frequently Asked Questions About Saunas and Sleep

Q1: Why can you sleep deeply after using a sauna?

By entering a sauna, your core body temperature temporarily rises. As your body temperature decreases afterward, natural drowsiness occurs. This utilizes the human body temperature rhythm, which is high during the day and low at night. Additionally, alternating cold baths in the sauna promote the secretion of serotonin, stabilizing emotions and providing a relaxing effect. Together, these lead to quality sleep.

Q2: When is the best time to use a sauna?

The ideal timing for using a sauna is about 2 hours before bedtime. This is because it takes some time for the core body temperature to start decreasing after the sauna. Using the sauna at this timing creates a better sleep environment through the subsequent natural body temperature drop.

Q3: How often should I use the sauna?

A frequency of about 2 to 3 times a week is recommended. However, the appropriate frequency varies depending on individual health conditions and lifestyle, so find a pace that feels comfortable for you. It’s important to do it within a range that you can continue without strain.

Q4: Is there a problem with being active after leaving the sauna?

Yes, there is. Being active immediately after leaving the sauna can cause your body temperature to rise again, disrupting the autonomic nervous balance and relaxation effect you have just achieved. Ideally, rest in a quiet environment and go to bed as is.

Q5: What effect does it have on the autonomic nervous system?

In daily life, such as work, the sympathetic nervous system (ON) tends to dominate, leading to a state of tension. However, the sauna can make the parasympathetic nervous system (OFF) dominant. This switch allows both body and mind to relax, leading to a “settled” state, which connects to comfortable sleep.

Summary

Saunas have a deep sleep effect. This is mainly due to core body temperature regulation, improvement of autonomic nervous balance, and promotion of serotonin secretion. Importantly, using it at the right timing and method is crucial. At the end of the day, spend a relaxing time and incorporate it at your own pace. This habitual process is the key to comfortable sleep.

Summary of Sauna Effects and Sleep Improvement

Saunas influence body temperature regulation and the autonomic nervous system, promoting high-quality sleep. Specifically, the temporary rise in body temperature due to the sauna, followed by a natural decrease, induces drowsiness and leads to quality sleep. This mechanism balances the sympathetic and parasympathetic nerves, creating a relaxed state of mind and body.

Additionally, the deep non-REM sleep obtained in the initial stage, known as the “Golden 90 Minutes,” is also noteworthy. As shown in many studies, over 75% of people feel an improvement in sleep after using a sauna. Against this backdrop, “Sauna” is spreading as a new health method in modern society.

It also helps with fatigue recovery and stress reduction, and by stimulating the autonomic nervous system, it may lower cortisol levels (stress hormone). However, in some cases, it can have the opposite effect, so it’s important to use it at a pace that suits you. The recommended timing is 1 to 2 hours before bedtime, as this time frame allows for a smooth preparation for sleep without strain.

Overall, “Sauna” offers not only relaxation effects but also a wide range of health benefits. However, attention is needed for safe and comfortable habituation.

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