温泉の効能は成分によって違います。しかし成分による効能もさることながら一般的な効能もあります。神経痛、筋肉痛、関節痛、肩こり、冷え性、慢性消化器病、疲労回復などは体が温まることによって（注1）緩解する症状です。日本は昔から湯治といって温泉を病気の治療に役立てていました。いまでも各地の温泉に湯治場が設けられています。例えば秋田県にある玉川温泉は効能書きには癌に効くとは書かれていないにもかかわらず、口コミで日本で一番癌に効く温泉と言われて常に湯治客でいっぱいです。希望者が多くて湯治が出来ない人が続出したので、直ぐ近くに新玉川温泉が開発されたほどです。玉川温泉は強酸性（pH1.05）の温泉という点では日本一です。また微量の放射能を含有しています。強力すぎて長時間湯に浸かることができないので湯治客は温泉を飲んだり、蒸気を吸入したり岩盤浴をして過ごします。玉川温泉での湯治によって病気が治るとまでは断言できませんが、病人の免疫力が増加して、かなり体調がよくなるらしいです。体を温めることが免疫力強化に役立つことは知られています。ですから玉川温泉に限らず全ての温泉に病気を回復させる力があると思います。 日本には約2万の温泉があると言われていますから、外国の観光客にも温泉を楽しんでもらいたいです。裸になって一緒に入浴する習慣がない国から来た人にとって、温泉は日本文化を知るいい機会になると思います。珍しい温泉もあります。海や川の中に出現することもあります。動物が入る温泉もあります。地獄谷温泉では猿の入浴が見られます。指宿の砂湯は「砂むし」と呼ばれて観光客に人気が高いです。海辺に浅く掘った砂の上に浴衣を着て寝て、上から砂をかけてもらいます。10分から15分の入浴で全身が温まり汗が出ます。海を見ながらの入浴は（注2）爽快です。このように一口に温泉と言っても様々です。 日本に来たからには一回ぐらいは温泉に入ってみたらどうでしょうか。その際、気をつけることは、入浴のマナーを守ることと、入りすぎて（注3）湯中りを起こさないことです。湯中りとは全身の疲労感、食欲不振、頭痛を始め様々な体調不良のことです。しかし直ぐに治る症状は、湯治により現れる自然な反応であり、むしろ温泉の効果を表すものと考えられています。最近は外国人も温泉地に大勢来ます。英語や中国語あるいは韓国語の入浴方法や成分表が書かれていますから、よく読んで温泉を楽しんでもらいたいです。
The efficacy of hot springs varies depending on their components. However, in addition to the efficacy based on components, there are also general benefits. Symptoms such as neuralgia, muscle pain, joint pain, stiff shoulders, cold sensitivity, chronic digestive disorders, and fatigue recovery are alleviated by warming the body (Note 1). Japan has long used hot springs for medical treatment, a practice known as 'yūji'. Even today, hot spring treatment facilities are established in various regions.
For example, Tamagawa Onsen in Akita Prefecture is always packed with patients seeking therapeutic bathing, widely regarded through word of mouth as the most effective hot spring in Japan for cancer, despite not being officially listed as having such efficacy. The demand was so high that many people were unable to receive treatment, leading to the development of Shin-Tamagawa Onsen nearby. Tamagawa Onsen is the most strongly acidic hot spring in Japan (pH 1.05). It also contains trace amounts of radioactivity.
The water is so potent that bathers cannot soak in it for extended periods, so health tourists spend their time drinking the hot spring water, inhaling the steam, or enjoying rock baths. While it cannot be definitively stated that health treatments at Tamagawa Onsen cure illnesses, it is said that patients' immunity increases and their overall condition improves significantly. It is well known that warming the body helps strengthen the immune system. Therefore, I believe that not only Tamagawa Onsen but all hot springs possess the power to aid in recovery from illness.
It is said that Japan has about 20,000 hot springs, so I want foreign tourists to enjoy them as well. For people coming from countries without the custom of bathing naked together, I think hot springs are a great opportunity to learn about Japanese culture. There are also unusual hot springs that sometimes appear in the sea or rivers. Some hot springs are even used by animals. At Jigokudani Onsen, you can watch monkeys bathing. The sand baths in Satsuma, known as 'suna-mushi,' are very popular with tourists.
Wearing a yukata, lie down on the shallowly dug sand by the seaside and have sand poured over you. A 10 to 15-minute bath will warm your entire body and induce sweating. Bathing while gazing at the sea (Note 2) is refreshing. As you can see, hot springs vary greatly despite being generally referred to as such. Since you are in Japan, why not try bathing in a hot spring at least once? When doing so, remember to observe bathing etiquette and avoid staying in the water too long (Note 3) to prevent heat exhaustion.
Yaku-nakari refers to various physical discomforts, including whole-body fatigue, loss of appetite, and headaches. However, these symptoms, which resolve quickly, are considered natural reactions induced by hot spring therapy and are actually seen as indicators of the hot spring's effectiveness. Recently, many foreign visitors have come to hot spring resorts. Since bathing instructions and ingredient lists are provided in English, Chinese, or Korean, please read them carefully to fully enjoy the hot springs.
