After an onsen or sauna, you start to crave something salty or something warm. In Japan, this is casually called sauna-meshi ("sauna food"), or sa-meshi for short, and the classic dishes are easy to find in restaurants inside bathhouses and in the eateries of onsen towns.

There is something to do before you eat, though. First replace fluids (and salt too if you have sweated a lot), rest a little, and then choose your meal: that is easiest on the body, because sweating does not only cost you water. This article covers how to think about hydration, the classic sauna meals, how to choose a drink, and cautions about alcohol.

This article provides general information. Alcohol makes dehydration worse, so be careful about drinking right after bathing or a sauna. If you have a chronic condition or are feeling unwell, do not push yourself.

First, hydrate: not just water, but salt too

Sweat is made from body fluids, so it contains electrolytes such as sodium (salt). When you sweat a lot, you lose salt along with water. As a rough guide, one measurement found that soaking in 41°C water for 15 minutes and then resting for 30 minutes loses about 800 ml of fluid (internal data from Otsuka Pharmaceutical).

The point to watch here is that drinking large amounts of plain water dilutes your body fluids, which can switch off your thirst and lead to what is called voluntary dehydration. In extreme cases, there is also a risk of hyponatremia, in which the sodium in the blood becomes too diluted. When you have sweated a lot, replace a moderate amount of salt as well as water. As a heat-illness measure, Japan's Ministry of the Environment gives 0.1–0.2% salt water (1–2 g of salt per liter of water), or sports drinks and oral rehydration solutions containing sodium, as a guide.

Classic sauna meals

The dishes you see most at Japanese bathhouses are ramen, udon, soba, curry, set meals and rice bowls. They make it easy to get salt and carbohydrates, and they are easy to order inside. People who want a proper meal often choose ramen or curry, and those who want something light udon or soba.

At super sento and sauna bathhouses, many restaurants let you walk in wearing the loungewear provided, which makes it easy to combine a meal with a rest. In onsen areas, on the other hand, going out to eat the local food is well worth it: seafood by the coast, wild mountain vegetables or local hot pots in the mountains, and in some areas, such as Beppu, steamed dishes are the specialty. After bathing, sweets such as ice cream, pudding and onsen manju are also classics, and they make an easy light snack.

Drink culture: Oropo and more

A well-known after-sauna drink is Oropo, a custom mix of Oronamin C and Pocari Sweat said to have originated at a sauna in Nishi-Azabu, Tokyo (it is not an official Otsuka Pharmaceutical product). It is one of the drinks that became a standard as sauna culture spread. It is covered in detail in Oropo and Sauna Drinks.

Drinks like these are to be enjoyed as part of the culture; they do not promise any special recovery effect. Simply enjoy them as a tasty extension of rehydrating.

Cautions about drinking alcohol after bathing or a sauna

Enjoying beer or sake is part of the culture too, but avoid launching straight into drinking when you are somewhat dehydrated. Alcohol is a diuretic: it suppresses the antidiuretic hormone and increases the amount of urine, so the more you drink, the more water tends to leave your body. For a body that has just been sweating, it can have the opposite effect to what you need.

In addition, drinking temporarily lowers blood pressure, and the heat of bathing lowers it further. Japan's Consumer Affairs Agency also warns against bathing after drinking or while alcohol is still in your system. If you do drink, it is easier on the body to first have some water and food. Beer After Sauna is also worth reading.

What to eat first, and when

Eating or drinking a lot all at once right after bathing can actually leave you more tired. It is more relaxing to sit down and rest for a moment first, have something to drink, and then order. Japan's Ministry of the Environment's onsen precautions also say to avoid bathing right before or right after a meal; put the other way round, it is gentler on the body to leave a little time after bathing before you eat.

Your appetite may be strong after a sauna, but overeating can make the journey onward or going to bed uncomfortable. On days when you have plans afterward, adjust the amount especially carefully. For guidance on how long and how often to bathe, see also How Long and How Often to Bathe in an Onsen.

FAQ

What should I drink first after an onsen or sauna?

Fluids first. For light sweating, water or barley tea is enough, but when you have sweated a lot, a sports drink or oral rehydration solution that also contains salt is better.

Is it enough to drink plenty of water?

When you sweat heavily, plain water alone dilutes your body fluids, and voluntary dehydration, in which dehydration actually gets worse, can occur. Replace a moderate amount of salt as well.

Is it okay to drink beer right after a sauna?

It is not recommended. Alcohol makes dehydration worse through its diuretic effect and also lowers blood pressure. Have water and food first, then keep it to a small amount.

What are the classic sauna meals?

Ramen, udon, soba, curry, set meals and rice bowls are the classics. People who want a proper meal choose ramen or curry; those who want something light choose noodles.

Summary

After an onsen or sauna, it is easiest on the body to replace fluids first (and salt too if you have sweated a lot), rest a little, and then choose your meal. The classic sauna meals are ramen, set meals and rice bowls, and the experience differs depending on whether you eat simply inside the bathhouse or enjoy local food in an onsen town. Alcohol makes dehydration worse, so have only a little, after water and food. Think of the meal as part of the bathing experience, and the whole trip is likely to be more satisfying.

Sources

• Ministry of the Environment, Heat Illness Environmental Health Manual (guidelines for water and salt intake)
• Consumer Affairs Agency, Beware of Bathing Accidents Among Older People, Which Increase in Winter (bathing after drinking)
• Ministry of the Environment, Contraindications and Bathing Precautions for Onsen