Why the study was conducted
In 2010, the Canadian Journal of Diabetes published the results of a clinical study conducted by a family practice physician who wanted to understand how a far infrared sauna’s (FIRS) cardiovascular benefits affected people with type 2 diabetes.1 At the time, Dr. Richard Beever was a clinical assistant professor of family medicine at the University of British Columbia and wanted to find solutions he could feel confident about recommending clinically to help people with type 2 diabetes get healthy, and in particular lower the risks of congestive heart failure.
He wanted to find ways to help stop the epidemic of obesity, hypertension, diabetes, and cardiovascular disease. Knowing that having multiple factors increase the risk of heart disease, especially for diabetics, he was looking for valid non-drug ways to help decrease any of those factors for his patients. Dr. Beever had recently published a summary of the evidence to support infrared sauna claims of a wide range of numerous health benefits, so it was fresh on his mind that the cardiovascular benefits were significant.2,4
“As infrared heat penetrates more deeply than warmed air, users develop a more vigorous sweat at a lower temperature than they would in traditional saunas,” he told Time magazine in 2017.
Because diabetes is a major risk factor for cardiovascular disease and weight management is a critical factor, the doctor got approval from the University of British Columbia and the Northern Health Authority Ethics Review Boards to investigate the effects of far infrared sauna on people with diabetes specifically.
How the study was conducted
Researchers applied a sequential, longitudinal interrupted time series cohort design offering the unique advantage of allowing subjects to serve as their own controls.
What does this mean? The gold standard for evaluating the causal effect of an intervention is a randomized controlled trial (RCT). However, RCTs do have limitations. They can be costly, unethical, or impractical to conduct. Often, researchers must consider alternative designs to evaluate interventions, and quasi-experimental studies are a valid solution that are not randomized and may use both pre-and post-intervention data. Interrupted time series is considered one of the strongest quasi-experimental designs.3
For the intervention, Dr. Beever used a Sunlight Armana 3 (the precursor to Sunlighten Signature 3) far infrared sauna three times per week for 20 minutes at the 150-degree default setting over a three-month period during winter of 2007-08.
Subjects were asked to refrain from starting any new diets or herbal medications and to maintain their current exercise routine. An exercise routine and medication review were conducted during the baseline and follow-up interviews, so any improvements could not be attributed to any changes other than the addition of infrared sauna.
- 20 participants with managed type 2 diabetes and no contraindications
- 14 female
- 6 male
- Age range 50-75 (average age 66.5 years)
- Measured height, weight, waist circumference, hip circumference, blood pressure, glycated hemoglobin, fasting blood glucose, and fasting lipid profile
- Blood pressure was measured using BPtru automated blood pressure monitor; 5 measurements taken 2 minutes apart, accuracy similar to a 24-h ambulatory BP
- Baseline measurements were taken within one week prior to starting sauna sessions
- Post-intervention measurements were taken between 1 and 3 days after the last sauna session, allowing adequate time for rehydration
Beever improved upon earlier studies: he included a larger sample size for a substantially longer duration with blood pressure measurements taken 24 hours after the last session. He also felt that having a community-based study with volunteers rather than the inpatient hospital setting used for previous studies allowed a more real-world use of the infrared sauna as a therapeutic lifestyle intervention. The study relied on participants’ self-motivation to attend the study sessions.
What the study concluded
In addition to answering the original question of cardiovascular benefits for those with type 2 diabetes, the study found some important additional key insights. Results showed the following benefits of regular infrared sauna use1:
- Lowers blood pressure – The study shows FIRS are beneficial for lowering blood pressure in those with type 2 diabetes by a significant clinical relevance (6.4 mm Hg). Blood pressure control is the single most important risk-reduction strategy for patients with type 2 diabetes for preventing CHF (congestive heart failure). The study concluded that regular use of FIRS may serve as a useful nonpharmacological alternative in treating hypertension.
- Decreases waist circumference - Up to 90% of people with type 2 diabetes are overweight. Obesity is a national and global epidemic and a leading cause of morbidity and mortality. Dr. Beever’s study findings suggest FIRS may reduce waist circumference. The statistical clinical relevance of lowering waist circumference imparts significant benefits to those with obesity, diabetes, hypertension, coronary artery disease, hyperlipidemia, obstructive sleep apnea, arthritis, metabolic syndrome, and polycystic ovarian syndrome.
- An easy habit to create - Uptake of FIRS use was greater than standard lifestyle interventions: results found participants stuck to the infrared sauna routine 75% more than other lifestyle adjustments. In his report, Dr. Beever explained this importance: “Effective lifestyle modifications that have high patient uptake are key to preventing and treating the current epidemic of lifestyle-induced chronic disease. FIRS may be a novel therapeutic intervention in this regard.”
- An effective exercise option - Thermoregulatory demands of maintaining homeostasis during FIRS therapy impart endocrine and cardiovascular stress. Although many subjects were sedentary, a subjective theme became apparent: FIRS use was similar to a moderate exercise regimen, except that participants reported it was “much more relaxing” and was “like exercise without exercising.” FIRS may be an effective lifestyle adjuvant, or helper, especially for those finding it difficult to participate in traditional exercise programs.
The study did not find FIRS effective for lowering weight, blood glucose, cholesterol or triglyceride levels.
No participants experienced any adverse events (light-headedness, heat rash, heat exhaustion, or heat stroke).
Why This Study Matters
Our bodies are complex, integrated systems and the cardiovascular system is closely linked to many diseases and conditions. Heart disease and weight loss are connected—researchers say the risk of heart disease is associated with weight, especially excess abdominal fat and waist circumference. A high-risk waistline is 35 inches or higher for women and 40 inches or higher for men.5 Managing a healthy weight and waistline isn’t about how you look or about the strain it places on muscles, joints and bones. It's one of the key risk factors for developing coronary artery disease when plaque builds up in your arteries, which can lead to heart attack or stroke.
From the challenges of those living with type 2 diabetes, we can gain insight and hope from Dr. Beever’s study, which supports the use of far infrared sauna for weight management and heart health.