The Science Behind The Practice

Researchers at Colorado State University have undertaken two studies of the benefits of the Original Hot Yoga series, one in 2008 and one in 2014. The first study had a group of test subjects taking three classes per week for eight weeks, and showed that even this relatively short program produced significant improvements in balance, and also improvements in leg strength and muscle control for the less-steady subjects. [1] The second study, in which the research subjects were all healthy young adults leading a relatively sedentary lifestyle, showed significant gains in spine, hamstring and shoulder flexibility and improved whole-body strength. [2]

Anecdotal evidence has showed Original Hot Yoga to be a highly effective treatment for sufferers of depression. There is now a study underway at Massachusetts General Hospital, where a team of psychiatrists will study the effectiveness of Original Hot Yoga as a means to reduce the symptoms of depression in a group of patients who are new to this practice. Maren Nyer, PhD, director of Yoga Research in the MGH Depression Clinical and Research Program at MGH says: “Hot yoga, practiced by a growing number of people, appears to be a promising treatment for depression. It provides intensive exercise and mindfulness, both shown as effective treatments for depression. Regular practice of hot yoga may regulate certain physiological functions that could contribute to the reversal of a depressed state.” [3]

However, the heated environment is a completely understudied domain with regard to its healing effects for depression. “Although there is only minimal empirical evidence, heat has traditionally been used to promote wellness,” says Maurizio Fava, MD, director of the MGH Depression Clinical and Research Program and professor of Psychiatry at Harvard Medical School. “The heated environment may enhance the antidepressant effects of this form of yoga.” As of April 2015 the study is still ongoing. [4]

A recent study presented at the Anxiety and Depression Association of America’s 2015 conference provided empirical data showing Original Hot Yoga to be effective for treating anxiety, depression and stress in women. The study examined a number of at-risk women who were suffering from mildly elevated anxiety, moderate depression and high stress. These women had not practiced yoga for the past year, and were randomly assigned to take two Original Hot Yoga classes per week. The results showed that the women taking the yoga classes presented greater decreases in anxiety, stress and depression than the test subjects who didn’t do any yoga. "Clinicians treating women who are stressed, anxious, and depressed should consider investigating some form of yoga therapy," said Dr Hopkins DeBoer, lead researcher for the study. "I think yoga pairs nicely alongside psychotherapy for a depressed mood, anxiety and stress in women." [5]

The longest running study of Original Hot Yoga to date is the 5-year study of Original Hot Yoga as a counter measure to bone loss and osteoporosis. Over the last decade it has been established that the best way to take preventative action against bone loss, and thus to prevent fragility fractures, is to engage in physical activity. However, the type of high intensity activities that may be the most advantageous for increasing bone density are not always viable options for the elderly and ageing, because many of them already have osteoporosis and are incapable of such vigorous movements. Weight bearing exercises have shown to increase the risk for this group to develop joint-related disorders such as osteoarthritis, and most low-impact forms of exercise fail to ameliorate the problem of decreased bone density. [6]

The osteoporosis and bone loss study was undertaken at the Bone Density Clinic at the Los Angeles Orthopaedic Hospital, and it included a number of women between the ages of 30 and 59. The researchers measured the bone mineral content of the proximal femur and lumbar spine in their subjects at the outset of the study, and then again, five years later. The results showed that the practice of Bikram yoga may preserve or even increase bone density, if practiced three times per week or more. The conclusions of the study indicate that Original Hot Yoga may be an effective countermeasure for preventing osteoporosis. [7]

There have been numerous testimonials on the effectiveness of a regular Original Hot Yoga practice to counteract the symptoms of diabetes. Some diabetics have even reported controlling their blood glucose levels without having to use insulin. A pilot study was undertaken in 2012 at the University of Texas, in Austin, Texas. The results of this study showed that adults at risk of Type 2 diabetes reduced their blood glucose levels as a result of a regular (three times per week) Bikram yoga practice. The test subjects had a mean age of 46 and were classed as ‘obese’. The study results showed that only eight weeks of practice noticeably lowered their blood glucose levels. [8]

Multiple studies have showed improvements in glucose response to traditional exercise (i.e. treadmill walking), but very few have shown the same with yoga. What makes Original Hot Yoga beneficial for metabolism could be the heat, as other studies have found similar benefits of heat-therapy over time. The authors of the research paper concluded that: “The findings of the current investigation unveil Original Hot Yoga as a new therapeutic tool in the amelioration of metabolic dysfunction with age and obesity. Original Hot Yoga may be an ideal alternative to traditional exercises, especially in older or obese adults, due to its low impact nature.” [9]

Another area where anecdotal evidence, testimonials and stories are overwhelming in their numbers, is the positive effect a regular Original Hot Yoga practice can have on sleep. Again and again we hear students who have suffered for years from insomnia and irregular sleep patterns saying that, even after their very first class, they “slept like a baby”. Many also testify that with a regular practice, they no longer need sleep remedies to help with insomnia, nocturnal awakenings and restless sleep patterns.

Again, this is an area where more research is needed. To date there is only one study on the subject, a pilot study on subjective and objective sleep parameters, undertaken by researchers at Massachusetts General Hospital. Since sleeping in a laboratory setting can be disturbing to sleep, and may provoke anxiety, the measurements were taken during home sleep monitoring. The testing period was relatively short (14 days) and the test subjects, who were all otherwise healthy young adults, were told to practice an Original Hot Yoga class at least two times during the testing period, on days of their own choosing. Their sleep parameters were measured on “yoga days” and on “non-yoga days”. [10]

This was only a pilot study, with a limited number of test subjects (13 people), and the results were inconclusive for insomnia and total sleep time. However, the results showed that Original Hot Yoga was associated a significantly faster return to sleep after nocturnal awakenings. The conclusion of the study was that more research was needed, and that “Of particular interest is whether habitual performance of yoga would reveal an evolution of changes in sleep architecture, perhaps from acute (restricted to the day of yoga) to chronic (sleep assumes an improved and more stable architecture)." [11]