Nature's Jacuzzi, The Heart Bath

Best Carbon Dioxide Spring Hot Springs Ranking

6 hot springs

Carbon dioxide springs contain a high concentration of dissolved carbonic acid gas, causing tiny bubbles to cling to the skin when bathing. This type is relatively rare in Japan but has long been used in Europe as 'the heart bath.'

As carbon dioxide is absorbed through the skin, it dilates blood vessels and promotes circulation, providing warming benefits even in lukewarm water without straining the heart.

Ranking Criteria

RANK1

Nagasaki

Natural Carbonated Hot Spring Nomon-yu

含鉄・二酸化炭素－カルシウム－炭酸水素塩泉

Secludedness

Natural Source FlowOvernightDay Trip

Minabe Onsen Tsurunoyu

含二酸化炭素－ナトリウム－炭酸水素塩泉

Secludedness

Natural Source FlowOvernightDay Trip

Togayama Onsen Tennyo no Yu

含二酸化炭素－カルシウム（・マグネシウム）－炭酸水素塩泉

Secludedness

Circulation SystemDay Trip

Yuzanso Asankotonami

単純二酸化炭素泉

OvernightDay Trip

RANK5

Oita

Hakusui Kosen Kurodakeso

含二酸化炭素－カルシウム（・マグネシウム）－炭酸水素塩泉

Natural Source FlowOvernightDay Trip

RANK6

Gifu

Yuya Onsen Sengakukan

単純二酸化炭素泉

Natural Source FlowOvernight

Comparison of Ranked Hot Springs

Name	Prefecture	Water Quality	Source-fed	Onsen Value
Natural Carbonated Hot Spring Nomon-yu	Nagasaki	含鉄・二酸化炭素－カルシウム－炭酸水素塩泉	Natural Source Flow	3
Minabe Onsen Tsurunoyu	Wakayama	含二酸化炭素－ナトリウム－炭酸水素塩泉	Natural Source Flow	3
Togayama Onsen Tennyo no Yu	Hyogo	含二酸化炭素－カルシウム（・マグネシウム）－炭酸水素塩泉	Circulation System	1
Yuzanso Asankotonami	Kagawa	単純二酸化炭素泉	-	-
Hakusui Kosen Kurodakeso	Oita	含二酸化炭素－カルシウム（・マグネシウム）－炭酸水素塩泉	Natural Source Flow	-
Yuya Onsen Sengakukan	Gifu	単純二酸化炭素泉	Natural Source Flow	-

Frequently Asked Questions

Q.Why do tiny bubbles cling to my skin in a carbon dioxide spring?

A.Carbonic acid gas dissolved in the water vaporizes from body heat and clings to the skin's surface as tiny bubbles.

Q.Why is the carbon dioxide spring called 'the heart bath'?

A.The gas dilates blood vessels and promotes circulation, providing a warming effect even at lower water temperatures, putting less strain on the heart.