Is cold plunge bad for your heart?

These days it’s hot to be cold. From celebrities installing personal pools dedicated to cold plunging to fitness centers offering cold plunge/hot sauna services, this centuries-old practice has become a modern trend. 

What is cold plunge? 

Cold plunge or cold-water immersion involves a person intentionally putting part or all of their body in cold water for a short amount of time. People take the plunge in pools, tubs, ice baths or natural bodies of water like lakes. 

How cold the water should be, how long you need to stay immersed and how often you take a dip may vary depending on who you ask.

• Temp. Many people ease into their polar plunges, starting in water that’s 50-60 degrees Fahrenheit. A more experienced cold plunger may want water that’s 40-50 degrees Fahrenheit. 
• Time. Most cold plunges are between 1-3 minutes long, with more experienced plungers often staying in longer.
• Frequency. To see how your body reacts, you should ease into cold plunging by only doing 1-2 per week to start.

What are the benefits of cold plunge? 

Fans of this frigid hobby will cite a long list of health benefits. Unfortunately, the jury—in this case medical research—is still undecided on many of these claims. While people have self-reported positive experiences, there hasn’t been much evidence-based research. But let’s explore what we do know about the body. 

Physical benefits

• Reduces inflammation. Athletes have been using cold-water immersion for quite some time to reduce swelling. In the same way people use an ice pack on sprains, strains and swelling, it’s believed the icy water helps numb the affected area and constrict blood vessels which lessens muscle damage and inflammation. 
• Limits muscle soreness. For those who cold plunge after a workout, it’s believed the reduction in inflammation will also limit delayed onset muscle soreness (DOMS) that creeps up in the hours or days after exercise. The research suggests that if you limit inflammation, you also decrease muscle soreness. However, more research is needed, and it’s unclear if that would help for everyday aches and pains.
• Decreases pain sensitivity. We’ve all felt how cold can numb an area of pain during an injury. Some people suggest that cold exposure can increase a person’s pain tolerance, but the long-term effects of cold plunging on pain sensitivity are also unknown.

Mindset shifts

• Cortisol changes. Cortisol is a stress hormone that has been found to dip below baseline levels after a cold plunge. This may create a calming effect. 
• Endorphins increase. Many people claim they cold plunge because it improves their mood. Research based on self-reporting supports these claims, which may be due to an increase in endorphins, sometimes described as the feel-good chemicals.
• Something else. It’s also possible that people are reacting positively to having a new ritual they enjoy. There are benefits to finding routine and taking part in group activities.

Are there risks to cold plunge? 

While cold plunge enthusiasts will tell you the benefits, there are risks to starting this activity. As a cardiologist, I strongly recommend anyone with a history of heart disease or a heart condition, consult their doctor before starting their cold plunge routine. 

Health risks

• Heart. When that cold shock hits it can create a few bodily responses. The cold shock response may cause your breathing, heart rate and blood pressure to rapidly increase. This may make you gasp and unintentionally take in water. It can also put added strain on your heart. 
• Arms and legs. Your body will try to protect your most important organs, which means if it’s super cold, blood will rush away from your arms and legs and to your core. When this happens, your arms and legs could lose strength and you could feel your coordination decline. 

Safety precautions

• Strength in numbers. Even experienced swimmers should be cautious about entering frigid water. Your body can go into a state of shock. It’s smart to implement the buddy system. If your body reacts poorly, someone is there to get help. 
• Ease into it. A cold plunge is meant to be quick. Don’t overdo it by staying in too long or going too often. 
• Seek shallow water. The National Center for Cold Water Safety reminds us that a person can drown even in shallow water so keep depth in mind when you’re choosing where to plunge. 

Who should avoid cold plunges? 

It’s always a good idea to talk to your doctor about new activities that could put extra strain on your body, especially if you have comorbidities. In general, I do not recommend this activity for people who have a history of heart problems. People on certain medications may also have an increased risk of complications. 

If this trend continues to gain steam, we may see future research studies into what’s really happening when we take the plunge.