A Sauna for Heart Health?

It is the end of October, the wind has teeth, and the only place you want to be is somewhere hot enough to make you forget it. If that somewhere is a sauna, there is some genuinely interesting research suggesting the heat might be doing your heart a favour as well.

Saunas have gone from a gym afterthought to a full-blown wellness trend, with Nordic spas, backyard barrel saunas, and hot-and-cold routines all over social media, and many of the claims are wildly overblown. The case for a sauna for heart health, however, rests on something sturdier: a long-running study from Finland, the country that practically invented the modern sauna. This guide covers what that study found, what it cannot prove, and how to use a sauna safely if you want it to be part of your winter.

Key takeaways

A Finnish study of 2,315 men aged 42 to 60, followed for about 20 years, linked frequent sauna use with fewer deaths from heart disease.

Men who used a sauna four to seven times a week had a 63 per cent lower risk of sudden cardiac death than men who went once a week.

The study shows a link and cannot prove cause and effect, and it included only middle-aged men using traditional dry saunas.

Heat raises your heart rate and widens your blood vessels, which may explain part of the benefit.

People with heart conditions, unstable or low blood pressure, a history of fainting, or a pregnancy should check with a doctor first.

What did the Finnish sauna study find?

The Finnish sauna study that most people point to appeared in JAMA Internal Medicine in 2015. Researchers followed 2,315 men in eastern Finland, aged 42 to 60, for a median of about 20 years. They grouped the men by how often they used a sauna, from once a week to two or three times a week to four to seven times a week, and tracked who went on to die of heart problems.

The more often the men used a sauna, the lower their risk. Compared with men who went once a week, those who went four to seven times a week had a 63 per cent lower risk of sudden cardiac death. They also had a 50 per cent lower risk of dying from heart and blood vessel disease, and a 40 per cent lower risk of dying from any cause. Even two or three sessions a week were linked to a 27 per cent lower risk of dying from heart and blood vessel disease.

The more often the men in the Finnish study used a sauna, the lower their risk of dying from heart problems.

Where does the sauna research fall short?

The first thing to understand is that this kind of study shows a link between two things, which is different from proving that one causes the other. The researchers observed that men who used saunas more often had better outcomes, though they could not show that the heat itself made the difference. A man with time for a sauna most days of the week may also have a less stressful job, more free time, or better health to begin with.

The second limit is who took part. The sauna research included only middle-aged Finnish men, so the results may not apply in the same way to women, younger or older adults, or people with very different lifestyles. Everyone in the study used a traditional Finnish sauna, which is dry heat at a high temperature. That means the findings say little about infrared saunas, steam rooms, or hot tubs, which work differently.

The findings are still promising, and the researchers themselves called for further studies to work out how sauna bathing and heart health are connected.

How might heat help your blood vessels?

When you sit in a hot sauna, your heart rate rises, and your blood vessels widen to help your body release heat. Cardiologists often compare that response to light or moderate exercise, since the heart works harder while blood pressure tends to dip. Our guide to checking your resting heart rate explains what that number normally looks like, and why it changes with heat and activity.

Over time, repeated exposure may help your blood vessels stay flexible, which matters for blood pressure. That same widening is why blood pressure can drop when you stand up after a session. It is also one more reason the numbers on a home monitor shift so much from hour to hour, as our guide to why your blood pressure numbers keep changing explains.

There is a simpler explanation worth keeping in mind as well. For many people, a sauna is a rare stretch of time to sit still, put the phone away, and unwind, and regular stress relief and better sleep are good for your heart on their own.

How do you use a sauna safely?

If you are healthy and want to use a sauna safely and regularly, a few habits make a big difference.

Start short. Begin with sessions of about 10 minutes and build up gradually as your body gets used to the heat.

Drink water before and after. You lose a surprising amount of fluid through sweat, and dehydration makes dizziness more likely.

Skip the alcohol. Alcohol and heat together can lower your blood pressure and raise the risk of fainting and heart rhythm problems.

Leave as soon as you feel unwell. Get out right away if you feel dizzy, light-headed, sick to your stomach, or just not right.

Stand up slowly. Blood pressure can drop when you move from heat to standing, so sit for a moment before you get up.

Avoid the sauna when you are sick, especially with a fever, and do not use one alone if you have any condition that could make you faint.

A few habits make the heat easier on your body, and some people need a doctor's go-ahead first.

Can a sauna replace exercise?

Even if using a sauna for heart health does turn out to work, it cannot replace exercise or the other basics. Regular physical activity, not smoking, eating well, and keeping your blood pressure and cholesterol in a healthy range remain the habits with the strongest evidence behind them.

Think of a sauna as a warm, relaxing addition to a heart-healthy routine, especially through a long Canadian winter, rather than a shortcut around it. Cold weather tends to push blood pressure up as well, which our guide to why blood pressure has seasons walks through, so winter is a sensible time to check your numbers anyway.

When should you talk to a doctor first?

Talk to a doctor before you start if you have heart disease, very high or unstable blood pressure, low blood pressure, recent chest pain, or a history of fainting, and the same goes during pregnancy. Some medications, including several for blood pressure, change how your body handles heat. Guidance from Brown University Health notes that most people with stable heart disease can use a sauna with precautions, though an unstable condition or a very recent heart attack calls for waiting.

See a doctor promptly if you notice chest pain, shortness of breath, a racing or irregular heartbeat, or fainting during or after a sauna, since those symptoms need to be looked at. If chest pain is severe or comes with sweating, nausea, or pain spreading to your arm or jaw, call 911 right away instead of waiting to see whether it passes.

Frequently asked questions

Is a sauna good for your heart?

The best evidence for using a sauna for heart health comes from a large Finnish study that linked frequent sessions with a lower risk of dying from heart disease. The study can only show a link, and it included only middle-aged men. A sauna can be a pleasant addition to exercise and healthy eating, though it cannot replace them.

How often did people use the sauna in the Finnish study?

The men in the Finnish study used a traditional dry sauna anywhere from once a week to seven times a week. Those who went four to seven times a week had the lowest risk of sudden cardiac death. Even two or three sessions a week were linked to a lower risk than once a week.

How long should you stay in a sauna?

Most healthy adults can start with sessions of about 10 minutes and build up slowly as their body adjusts. Leave right away if you feel dizzy, light-headed, or unwell. Drink water before and after each session, and stand up slowly when you finish, because blood pressure can drop as you move from the heat.

Can you use a sauna if your blood pressure runs high?

Many people whose blood pressure is well controlled can use a sauna, though anyone with very high, unstable, or low blood pressure should ask a doctor first. Some blood pressure medications change how your body handles heat. Never combine a sauna with alcohol, which can drop blood pressure further and raise the risk of fainting.

Do infrared saunas have the same effect?

The Finnish findings come from traditional dry saunas at high temperatures, so they say little about infrared saunas, steam rooms, or hot tubs. Infrared saunas heat the body at lower air temperatures and may affect the heart differently. Treat any claim that they protect the heart in the same way with caution until more research is done.

Is it safe to use a sauna when pregnant?

Pregnancy is one of the times to check with your doctor or midwife before using a sauna. Heat can raise body temperature, lower blood pressure, and make dizziness and dehydration more likely. Your provider can tell you whether short, cooler sessions are reasonable for you or whether it is better to skip the sauna until after the baby arrives.

Your next step

The best sauna habit starts with knowing your heart is ready for it. The Medimap Health Hub has more on heart health. You can also find a family practice near you for a checkup, or book a visit at a walk-in clinic to get your blood pressure checked before your next winter session.

Disclaimer: This article is for general information only and is not medical advice. It does not replace a conversation with a doctor or other qualified health professional who knows your history. If you think you are having a medical emergency, call 911 or go to the nearest emergency department.