Social media is flooded with content positioning contrast therapy as an essential biohacking and wellness tool. From cold plunges and infrared saunas to traditional saunas, extreme hot and cold exposure is often promoted as a way to recover faster, boost energy and improve long-term health.
But just because these practices are popular doesn’t mean they are safe and good for everyone.
“Contrast therapy creates real physical stress on the body,” said Mike Elliott, senior director of Banner Sports Medicine High Performance Center. “That stress can lead to positive adaptations but it can also increase risk if someone isn’t a good candidate or misuses them.”
If you are considering contrast therapy, read on to learn more about saunas (both traditional and infrared) and cold plunging.
Why are extreme temperatures so popular?
Hot and cold therapies aren’t new. Athletes have used ice baths for decades. Saunas have been part of daily life in many cultures for hundreds of years.
What’s new is how often these tools are used for general wellness. Extreme temperatures trigger strong physical reactions, which is part of the appeal. Extreme heat and cold push the body outside its comfort zone. In response, the body works harder to maintain balance, or homeostasis.
“When you expose the body to hot and cold environments, heart rate, blood flow, hormones and the nervous system respond,” Elliott said. “Over time, the body can adapt and sometimes benefit.”
But “sometimes” is the key word.
Traditional saunas
A traditional sauna heats the air around you using heated rocks, an electric heater or a wood stove. The hot air first warms your skin. Then your core temperature rises. Your heart rate goes up, your blood vessels widen and you sweat a lot.
“The body’s response to a traditional sauna looks similar to aerobic exercise,” Elliott said. “Heart rate goes up, circulation improves and the body works to cool itself because its core temperature has increased.”
Benefits supported by research
Traditional saunas have been studied for decades, including long-term studies following large groups of people.
- Heart health and longevity: Frequent sauna use is linked with a lower risk of heart disease and death from all causes. Research shows a dose response, meaning more frequent and longer sessions are associated with greater benefit. “We see reduced blood pressure and improved blood vessel flexibility with regular sauna use. Those changes support cardiovascular health,” Elliott said.
- Brain health: Some long-term studies show that people who use traditional saunas often may have a lower risk of dementia and Alzheimer’s disease.
- Lung and immune support: Some research suggests regular sauna use is linked to a lower risk of asthma, COPD and pneumonia.
- Pain relief and recovery: Heat may reduce symptoms of osteoarthritis, rheumatoid arthritis, fibromyalgia and other chronic pain conditions.
- Hormonal and mood effects: Traditional sauna use can increase growth hormone levels, which support muscle repair and fat metabolism. Endorphins are also released, which may improve mood. Over time, stress hormone levels may normalize as the body adapts.
Drawbacks to consider
High temperatures are not well tolerated by everyone.
“People with heat sensitivity or unstable heart conditions may not tolerate traditional saunas safely,” Elliott said. “It’s also important to understand that most studies are observational, meaning they show associations rather than direct cause.”
How research supports using traditional saunas
- Temperature: 175-210 degrees F
- Session length: Five to 20 minutes
- Frequency: Daily, several times a week or even once per week shows benefits
Infrared saunas
Infrared saunas heat the body directly using infrared panels rather than heating the air. This raises core temperature and induces sweating at lower ambient temperatures.
“The lower heat can make infrared saunas feel more approachable,” Elliott said. “For some people, it’s an easier starting point.”
Potential benefits
Research on infrared saunas is shorter-term and less conclusive compared to research focused on traditional saunas.
- Heart and metabolic health: Some studies show reduced blood pressure and improved blood vessel function.
- Pain relief: Certain studies report reduced pain in people with rheumatoid arthritis and other chronic pain conditions.
- Stress and mood: Infrared sauna use may release endorphins, supporting relaxation and mood improvement. Hormonal changes appear smaller than with traditional saunas. “The lower temperatures likely create a smaller stress response, which may explain the differences in outcomes,” Elliott said.
Limitations
Many infrared sauna studies involve fewer participants, shorter timelines or manufacturer funding, which may bias results.
“We need larger, long-term studies to understand the benefits fully,” Elliott said.
How research suggests using infrared saunas
- Temperature: 115–140°F
- Session length: 15–30 minutes
- Frequency: Daily or several times a week
Cold plunges
Cold plunging typically involves immersion in water below 60°F, most often between 50 and 56°F.
“Cold exposure triggers an immediate stress response,” Elliott said. “Heart rate increases, breathing speeds up, blood vessels constrict and stress hormones are released.”
Shivering may occur as the body creates heat. Cold also slows nerve signals, which can reduce pain but may affect coordination and muscle function.
Potential benefits
- Muscle soreness and recovery: Cold plunges can reduce post-exercise muscle soreness by decreasing inflammation. “Athletes should understand that cold plunging immediately after training may reduce muscle-building signals,” Elliott said. “Timing matters.”
- Circulation response: After leaving the cold, blood flow increases as the body warms back up.
- Metabolic effects: Cold exposure increases energy expenditure and may improve insulin sensitivity by activating brown fat (a type of fat that keeps you warm when your body is cold).
- Stress and alertness: Some research shows reduced stress and increased alertness, though effects on sleep and mood are still being studied. “With repeated exposure, the body adapts,” Elliott said. “More frequent use doesn’t always mean more benefit.”
How research suggests using cold plunges
- Water temperature: 50–56°F
- Session length: Five to 20 minutes
- Frequency: Two to four times per week
Who should avoid these therapies?
Contrast therapies aren’t without risks.
Avoid cold plunges if you have:
- Heart disease
- Cold allergy (cold urticaria)
- Open wounds or infections
- Raynaud’s or peripheral vascular disease
- Weakened immune system
Higher risk groups: older adults, people on blood pressure medicines, blood thinners, stimulants, those with asthma or COPD, pregnant women, children and people with diabetes-related nerve damage.
Avoid saunas (traditional and infrared) if you have:
- Heart disease
- Kidney disease
- Active infection, fever or bleeding
- Are pregnant
Higher risk groups: People with high blood pressure, implanted medical devices, heat-sensitive conditions or taking diuretics or blood pressure meds.
Stop immediately if you feel:
- Chest pain
- Dizziness
- Confusion
- Shortness of breath
- Weakness
- Nausea
- Irregular heartbeat
- Trouble breathing
Tips for safely getting started
- Talk to your health care provider: Review your health conditions and medications.
- Start slow and build tolerance: Begin with warmer cold plunges (around 60°F) or lower-temperature infrared saunas.
- Never use these therapies alone: Because these therapies stress the body, it’s important to have someone with you or nearby in case of emergency.
- Set a timer: More is not better. Stick to recommended timeframes.
- Hydrate before, during and after: Dehydration and electrolyte imbalance are risks for everyone.
- Match the therapy to your goal: Recovery? Stress relief? Heart health? Your goal should guide how and when you use these tools.
Bottom line
Cold plunges, infrared saunas and traditional saunas can all offer benefits but they’re not magic. Extreme temperatures stress your body. Used wisely, that stress may help. Used carelessly, it can harm.
Listen to your body, go slow and always put safety first. If you have questions or concerns, talk to your health care provider or a Banner Health specialist.
