Why Do You Feel Worse After an Infrared Sauna?

Infrared saunas are meant to be relaxing, so it can be confusing when you come out with a headache, feel woozy or feel wiped out. Here are the usual causes, what to do right away, and how to avoid it next time.

Why you can feel worse after an infrared sauna

An infrared cabin is cooler than a traditional sauna, but it still heats your body. Cleveland Clinic says infrared saunas run at about 110 to 135°F (43 to 57°C) and warm your body more directly than hot air does. Harvard Health explains that in a sauna your pulse rises by 30% or more, more blood flows to your skin, and the average person sweats out about a pint during a short session. Most bad after-effects come from that heat and fluid loss:

• Dehydration: the NHS lists thirst, headache, feeling light-headed or dizzy, tiredness and dark yellow pee as signs.
• Too much heat: heat exhaustion causes tiredness, dizziness, headache, nausea, heavy sweating, pale clammy skin and cramps.
• A drop in blood pressure when you stand up: with more blood in your skin, standing up quickly can make you dizzy. The NHS calls this postural hypotension and advises getting up slowly.
• A session that was too long or too hot for you: Cleveland Clinic suggests beginners start at about 110°F for five to 10 minutes.
• Alcohol or certain medicines: Harvard Health advises avoiding alcohol and medicines that affect sweating before and after a sauna. A review in the American Journal of Medicine says alcohol in the sauna raises the risk of low blood pressure, irregular heartbeat and sudden death.
• Already being ill: Cleveland Clinic warns that sitting in the heat while you are sick stresses your body and “may make you feel worse”. See sauna when you are sick.
• An empty stomach or low blood sugar: especially if you take insulin or other diabetes medicines (see NHS low blood sugar).

Symptoms, likely causes and what to do

For more detail see dizzy, weak or cramping after a sauna, can a sauna cause headaches and is a sauna good for nausea.

Is it “detox”? No

A common claim is that feeling bad after an infrared sauna means toxins are leaving your body and you should push through. That is not true, and pushing through can be dangerous.

• Sweat is mostly water and salts. Researchers estimated in Environment International (2018) that sweat removes less than 0.024% of the pollutants (PCBs) a person takes in each day, and called it negligible.
• Your liver and kidneys clear waste products. A sauna does not speed this up in a way that would make you feel ill.
• Headache, nausea and dizziness after heat are warning signs. Cleveland Clinic says that if you suddenly feel dizzy or nauseated, you should get out of the sauna immediately.

What to do right now

The NHS recommends four steps for heat exhaustion:

1. Move to a cool place.
2. Take off unnecessary clothing.
3. Drink plenty of water. A sports drink or rehydration solution also helps replace salt lost through sweat.
4. Cool your skin with cool water and a fan. Cold packs wrapped in a cloth under the armpits or on the neck also help.

You should start to feel better within 30 minutes. If you feel faint, the NHS advises lying down with your legs raised. Call emergency services if you are still unwell after 30 minutes of cooling and fluids, or if you are confused, have hot skin that is not sweating, a fast heartbeat, fast breathing, a seizure or lose consciousness. These can be signs of heatstroke.

How to avoid feeling worse next time

• Start low and short: Cleveland Clinic suggests about 110°F for five to 10 minutes at first, then building up. Even experienced users should keep to about 20 to 30 minutes, and Harvard Health suggests no more than 15 to 20.
• Drink before and after: bring water into the sauna, as Cleveland Clinic suggests, and drink two to four glasses after (Harvard Health). See what to eat and drink after the sauna.
• Eat something light first: do not go in very hungry or straight after a big meal. See sauna before or after eating and sauna while fasting.
• No alcohol before or after. See can you drink alcohol in the sauna.
• Cool down gradually and sit for a minute before you stand up.
• Skip the sauna when you are ill, very tired or have not slept.
• Time your session: use our sauna timer.

Is an infrared sauna different from a traditional sauna?

Infrared cabins have cooler air than traditional saunas (110 to 135°F vs 150 to 195°F, according to Cleveland Clinic), and many people find them gentler. Because they feel milder, people often stay in longer, and a long session still heats you up and makes you sweat. Infrared panels also do not cause a sunburn; see can an infrared sauna burn your skin. For a full comparison, see infrared vs traditional saunas and can infrared saunas be dangerous.

When to talk to a doctor

• You feel unwell after almost every session, even short and cool ones.
• You faint, have chest pain or a pounding or irregular heartbeat.
• You have heart disease or uncontrolled high blood pressure. Harvard Health says to check with your doctor before using a sauna.
• You have multiple sclerosis. Cleveland Clinic says heat can temporarily make symptoms worse.
• You are pregnant. ACOG warns that heat from saunas early in pregnancy may harm the baby.
• You take insulin, diabetes medicines or medicines that affect sweating or blood pressure.

Frequently asked questions

Why do I get a headache after an infrared sauna?

The most common reasons are fluid loss and overheating. The NHS lists headache as a symptom of both dehydration and heat exhaustion. Drink water, rest somewhere cool, and keep your next session shorter and cooler.

Is feeling sick after an infrared sauna a sign of detox?

No. Nausea, dizziness and headache are signs that you got too hot or lost too much fluid. Sweat removes only tiny amounts of pollutants. Cleveland Clinic says to get out right away if you suddenly feel dizzy or nauseated.

Why do I feel so tired after an infrared sauna?

Heat makes your heart work harder and you lose fluid through sweat. Tiredness is a symptom of both dehydration and heat exhaustion. Rest, drink water and eat something light. If you are still very tired the next day, use shorter sessions.

Why do I feel dizzy when I stand up after a sauna?

In the heat, more of your blood goes to your skin. When you stand up quickly, your blood pressure can briefly drop, which the NHS calls postural hypotension. Sit for a moment, stand up slowly, and lie down with your legs raised if you feel faint.

How long should a beginner stay in an infrared sauna?

Cleveland Clinic suggests starting at about 110°F for five to 10 minutes and building up slowly. Even experienced users should keep sessions to about 20 to 30 minutes. Harvard Health advises no more than 15 to 20 minutes.

When is feeling unwell after a sauna an emergency?

Call emergency services if you still feel unwell after 30 minutes of cooling down and drinking fluids. The same goes for confusion, hot skin that is not sweating, a fast heartbeat, shortness of breath, a seizure or fainting. These can be signs of heatstroke.

Sources

• Cleveland Clinic, Infrared sauna benefits (110–135°F vs 150–195°F; start at 110°F for 5–10 min; 20–30 min max; get out if dizzy or nauseated; MS, pregnancy, illness)
• Harvard Health, Saunas and your health (pulse +30%, a pint of sweat, avoid alcohol and medicines, 15–20 min, 2–4 glasses of water)
• NHS, Heat exhaustion and heatstroke (symptoms, 4 steps, 30-minute rule, emergency signs)
• NHS, Dehydration
• NHS, Low blood pressure (hypotension) (postural hypotension, get up slowly)
• NHS, Fainting (lie down with legs raised)
• NHS, Low blood sugar (hypoglycaemia)
• Hannuksela & Ellahham 2001, Am J Med: Benefits and risks of sauna bathing (PubMed 11165553)
• Imbeault et al. 2018, Environment International (PubMed 29197670)
• ACOG, Can I use a sauna or hot tub early in pregnancy?