About the Research Databases

The Wellness Evidence team of doctor consultants selected four of the most respected evidence-based medicine databases that are also particularly useful for wellness-focused research: Natural Standard, The Cochrane Library, PubMed and the TRIP Database.

Please read “Important Things to Know,” including info on each database.

We’ve made researching a particular therapy simple by pre-searching the evidence at each database. (See evidence below.) However, please note that evidence-based medicine relies on a research hierarchy, because not all evidence is created equalLearn more about how the medical experts classify this research.

We’d like to hear from you. If there is a Wellness Evidence discipline you would like to see on these pages, please email us.

Natural Standard

An international research collaboration that systematically reviews (and limits its focus to) scientific evidence on complementary and alternative medicine (CAM). Founded in 2000, Natural Standard assigns a grade to each CAM therapy, reflecting the level of available scientific data for or against the use of each therapy for a specific medical condition.

Natural Standard is subscription-based, and each of the database’s monographs aggregates data from other resources like AMED, CANCERLIT, CINAHL, CISCOM, the Cochrane Library, EMBASE, HerbMed, International Pharmaceutical Abstracts, Medline and NAPRALERT – and 20 additional journals. Data analysis is performed by healthcare professionals conducting clinical work and/or research at academic centers, using standardized instruments pertaining to each monograph section


Relaxation techniques include behavioral therapeutic approaches that differ widely in philosophy, methodology, and practice. The primary goal is usually non-directed relaxation. Most techniques share the components of repetitive focus (on a word, sound, prayer phrase, body sensation, or muscular activity), adoption of a passive attitude towards intruding thoughts, and return to the focus.

Deep and brief methods exist. Deep methods include autogenic training, progressive muscle relaxation (PMR), and meditation (although meditation is sometimes distinguished from relaxation based on the state of “thoughtless awareness” that is said to occur during meditation). Brief methods include self-control relaxation, paced respiration, and deep breathing. Brief methods generally require less time and often represent an abbreviated form of a deep method. Other relaxation techniques include guided imagery, deep breathing/breathing control, passive muscle relaxation, and refocusing. Applied relaxation involves imagination of relaxing situations with the intention of inducing muscular and mental relaxation. Another popular technique is progressive relaxation, in which the individual is taught what it feels like to relax by comparing relaxation with muscle tension. Progressive muscle relaxation (PMR) is said to require several months of practice at least three times per week in order to be able to evoke the relaxation response within seconds. Relaxation technique instruction is available in many hospitals, in the community, in books, or on audiotapes/videotapes.

The term “relaxation response” was coined by Harvard professor and cardiologist Herbert Benson, MD in the early 1970s to describe the physiologic reaction that is the opposite of the stress response. The relaxation response is proposed to involve decreased arousal of the autonomic nervous system and central nervous system as well as increased parasympathetic activity characterized by lowered musculoskeletal and cardiovascular tone and altered neuroendocrine function.

Relaxation techniques may be taught by various complementary practitioners, physicians, psychotherapists, hypnotherapists, nurses, clinical psychologists, and sports therapists. There is no formal credentialing for relaxation therapies.

Clinical studies suggest that relaxation techniques may be beneficial in patients with anxiety, although these approaches do not appear to be as effective as psychotherapy. For conditions with a strong psychosomatic element, relaxation may be beneficial, although it is not clear if effects are long-term. Relaxation techniques may be used for stress management using self-regulation. There is not enough evidence to form firm conclusions about the effectiveness of relaxation for other conditions. Relaxation has also been suggested in patients after surgery to speed up recovery, require less pain medication, lower blood pressure, and reduce postoperative complications. Relaxation techniques are sometimes used by people with insomnia or other sleep disorders.

Evidence Table
The grades A-F ascribed to the specific health conditions below have a very specific meaning. i.e., a “C” can still mean evidence of benefit from a small randomized trial, etc. Read about what each grade actually means. Grade
Numerous human studies report that relaxation techniques (for example using audio tapes or group therapy) may moderately reduce anxiety, particularly in individuals without significant mental illness. Relaxation may be beneficial for phobias such as agoraphobia, panic disorder, work-related stress, and anxiety due to serious illnesses, prior to medical procedures, or during pregnancy. However, because there are many types of relaxation techniques used in studies, and many trials do not clearly describe design or results, a strong recommendation cannot be made without better human evidence.
Early research in patients with angina reports that relaxation may reduce anxiety, depression, frequency of angina episodes, need for medication, and physical limitations. Large well-designed studies are needed to confirm these results.
Preliminary studies of relaxation techniques in individuals with asthma report a significant decrease in asthma symptoms, anxiety, and depression, along with improvements in quality of life and measures of lung function. Further large trials in humans are needed to confirm these results.
Chemotherapy induced nausea and vomiting
Early human trials report that relaxation techniques may be helpful in reducing nausea related to cancer chemotherapy. Better quality research is necessary before a firm conclusion can be drawn.
There is promising early evidence from human trials supporting the use of relaxation to reduce symptoms of depression, although effects appear to be short-lived. Better quality research is necessary before a firm conclusion can be drawn.
Relaxation has been reported to reduce fibromyalgia pain. However, results from other studies are conflicting, and therefore further research is needed before a clear recommendation can be made.
Preliminary evidence suggests that relaxation techniques may be helpful for the reduction of migraine headache symptoms in adults. Study of relaxation in children with headaches has yielded unclear results. Additional research is necessary before a firm conclusion can be drawn.
Heart attack risk reduction
Early research of relaxation techniques in people who have had a heart attack suggests that fewer future heart attacks may occur when relaxation is regularly practiced. However, only a small number of patients have been studied, and better research is necessary before a firm conclusion can be reached.
Heart failure
Early studies suggest that progressive muscle relaxation training may benefit patients with heart failure when used as an adjunct to standard care.
High blood pressure
Relaxation techniques have been associated with reduced pulse rate, systolic blood pressure, diastolic blood pressure, lower perception of stress, and enhanced perception of health. Further research is needed to confirm these results.
Mental health and quality-of-life improvements have been seen in preliminary studies of HIV/AIDS patients. These findings suggest the need for further, well-controlled research.
Huntington’s disease
Preliminary research in patients with Huntington’s disease has evaluated the effects of either multisensory stimulation or relaxation activities (control) for four weeks, with unclear results. Further research is necessary before a conclusion can be drawn.
Several human trials suggest that relaxation techniques may be beneficial in people with insomnia, although effects appear to be short-lived. Research suggests that relaxation techniques may produce improvements in some aspects of sleep such as sleep latency and time awake after sleep onset. Cognitive forms of relaxation such as meditation are reported as being slightly better than somatic forms of relaxation such as progressive muscle relaxation (PMR). However, most studies in this area are not well-designed or reported. Better research is necessary before a firm conclusion can be drawn.
Irritable bowel disease
Early research in humans suggests that relaxation may aid in the prevention and relief of irritable bowel disease symptoms. Large, well-designed trials are needed to confirm these results.
Menopausal symptoms
There is promising early evidence from human trials supporting the use of relaxation techniques to reduce menopausal symptoms, although effects appear to be short-lived. Better quality research is necessary before a firm conclusion can be drawn.
Obsessive-compulsive disorder
Results of randomized controlled studies of relaxation techniques for obsessive-compulsive disorder show conflicting results. Further research is needed before conclusions can be drawn.
Osteoarthritis pain
In a randomized study of patients with osteoarthritis pain, Jacobson relaxation was reported to lower the level of subjective pain over time. The study concluded that relaxation might be effective in reducing the amount of analgesic medication taken by participants. Further well-designed research is needed to confirm these results.
Most studies of relaxation for pain, including post-operative pain and low back pain, are poor quality and report conflicting results. Better research is necessary before relaxation techniques can be recommended either alone or as an addition to other treatments for acute or chronic pain.
Paralysis (facial)
In a randomized clinical trial, mime therapy – including automassage, relaxation exercises, inhibition of synkinesis, coordination exercises, and emotional expression exercises – was shown to be a good treatment choice for patients with sequelae of facial paralysis.
Premenstrual syndrome (PMS)
There is early evidence that progressive muscle relaxation (PMR) training may improve physical and emotional symptoms associated with PMS. Further research is necessary before a conclusion can be drawn.
Rheumatoid arthritis
Limited preliminary research reports that muscle relaxation training may improve function and well-being in patients with rheumatoid arthritis. Additional research is necessary before a conclusion can be reached.
Smoking cessation
Early research reports that relaxation with imagery may reduce relapse rates in people who successfully completed smoking cessation programs. Better study is needed in this area before a firm conclusion can be reached.
Syncope (neurocardiogenic)
A small study showed that biofeedback assisted relaxation (BFRT) benefits patients with neurocardiogenic syncope. Further study is necessary to confirm these results.
Tinnitus (ringing in the ears)
Relaxation therapy has been associated with benefits in preliminary studies of tinnitus patients. Further research is needed to confirm these results.
Studies assessing relaxation to improve psychological well-being and “calm” in multiple types of patients have reported positive results, although the results of most trials have not been statistically significant. Although this research is suggestive, additional work is merited in this area before a firm conclusion can be drawn.
Myocardial infarction (heart attack)
Initial research in which patients were given an advice and relaxation audiotape within 24 hours of hospital admission for a heart attack found a reduction in the number of misconceptions about heart disease, but no benefits on measured health-related outcomes.
Post-traumatic stress disorder
Relaxation has been studied for post-traumatic stress disorder with no benefit seen in these patients.

In situations of stress, there is increased activity of the sympathetic nervous system, which leads to the “fight or flight” response. Physiologic changes include increased heart rate, blood pressure, rate of breathing, blood supply to the muscles, and dilation of the pupils. It has been proposed that frequent stressful situations may lead to negative effects on health, such as high blood pressure, raised cholesterol levels, gastrointestinal distress, or depression of the immune system.

In contrast to the stress response, relaxation is characterized by reduced sympathetic nervous system tone and increased parasympathetic activity. This may include decreased metabolism, blood pressure, oxygen consumption, and heart rate, as well as a feeling of calmness. Increased brain wave slow wave activity (measured on EEG) has been reported. Alterations in the immune system may also play a role (such as changes in cytokine activity).

It has been theorized that by learning how to self-initiate the relaxation response, negative effects of chronic stress may be counter-balanced. There are some reports that states of relaxation can be achieved after several seconds with practice. Massage, deep meditative states, mind/body interactive techniques, and certain types of music and sounds have been suggested as means of establishing a state of relaxation. Rhythmic, deep, visualized, or diaphragmatic breathing may be practiced. Mental imagery, biofeedback, desensitization, cognitive restructuring, and adaptive self-statements may also be included in techniques.

Jacobson muscle relaxation or “progressive relaxation” involves flexing specific muscles, holding that position, then relaxing the muscles. This technique often involves progressing through the muscle groups of the body one at a time, beginning with the feet, spending approximately one minute on each area. Progressive relaxation may be practiced while lying down or sitting. This approach has been suggested for psychosomatic disorders, for pain relief, to ease physical tension, to relieve “inner unrest,” to overcome psychosomatic disorders, and to relieve pain.

The Laura Mitchell approach involves reciprocal relaxation, moving one part of the body in the opposite direction from an area of tension, and then letting it go.

No formal credentialing or licensure exists for these relaxation techniques. Courses are offered at institutions including the National Institute for Clinical Applications of Behavioral Medicine (NICBM), the American Holistic Medical Association (AHMA), and the Center for Mind-Body Medicine (CMBM).


The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

Adjustment disorder, addiction, aging, alcohol abuse, Alzheimer’s disease, amnesia, anger (road rage), anti-spasm (pelvic floor spasms), arrhythmia (abnormal heart rhythm), balance, chronic fatigue syndrome, chronic obstructive pulmonary disease (COPD), cognitive disorders (neurogenic), communicative disorders, coronary artery disease, diabetes, drug abuse, dyspepsia, emotional distress, epilepsy, exercise performance, gastritis, gastrointestinal disorders, hemiplegia, herpes virus, high cholesterol, hyperactivity, immune system stimulation, increasing breast milk, infertility, ischemic heart disease, longevity, migraine, night eating syndrome, painful menstruation, panic disorder, Parkinson’s disease, peptic ulcer disease, pregnancy, preparation for surgery, psoriasis, psychiatric disorders, quality of life, repetitive strain injuries, rosacea, sleep disorders, social phobias, temporomandibular joint disorder, tension headache (adults), upper respiratory tract infections (children), warts, wound healing.


Many complementary techniques are practiced by healthcare professionals with formal training, in accordance with the standards of national organizations. However, this is not universally the case, and adverse effects are possible. Due to limited research, in some cases only limited safety information is available.

Most relaxation techniques are non-invasive and are generally considered safe in healthy adults. Serious adverse effects have not been reported. It is theorized that anxiety may actually be increased in some individuals using relaxation techniques and that autogenic discharges (sudden, unexpected emotional experiences including pain, heart palpitations, muscle twitching, crying spells, or increased blood pressure) may occur rarely. Scientific evidence is limited in these areas. People with psychiatric disorders such as schizophrenia/psychosis should avoid relaxation techniques unless recommended by their primary psychiatric healthcare provider. It is sometimes suggested by practitioners that techniques requiring inward focusing may intensify depressed mood, although scientific evidence is limited in this area.

Jacobson relaxation (flexing specific muscles, holding that position, then relaxing the muscles) should be used cautiously by people with illnesses such as heart disease, high blood pressure, or musculoskeletal injury.

Relaxation therapy is not recommended as the sole treatment approach for potentially serious medical conditions, and it should not delay the time to diagnosis or treatment with more proven techniques.


This information is based on a professional level monograph edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com): Dawn Costa, BA, BS (Natural Standard Research Collaboration); Jenna Hollenstein, MS, RD (Natural Standard Research Collaboration); Shaina Tanguay-Colucci, BS (Natural Standard Research Collaboration); Catherine Ulbricht, PharmD (Massachusetts General Hospital); Wendy Weissner, BA (Natural Standard Research Collaboration).


Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. Selected references are listed below.

  1. Andrasik F, Grazzi L, Usai S, et al. Pharmacological treatment compared to behavioural treatment for juvenile tension-type headache: results at two-year follow-up. Neurol Sci 2007 May;28 Suppl 2:S235-8.
  2. Blanchard EB, Greene B, Scharff L, et al. Relaxation training as a treatment for irritable bowel syndrome. Biofeedback Self Regul 1993;18(3):125-132.
  3. Boyce PM, Talley NJ, Balaam B, et al. A randomized controlled trial of cognitive behavior therapy, relaxation training, and routine clinical care for the irritable bowel syndrome. Am J Gastroenterol 2003;98(10):2209-2218.
  4. Davies S, McKenna L, Hallam RS. Relaxation and cognitive therapy: a controlled trial in chronic tinnitus. Psychol Health 1995;10:129-143.
  5. Engel JM, Rapoff MA, Pressman AR. Long-term follow-up of relaxation training for pediatric headache disorders. Headache 1992;32(3):152-156.
  6. Fichtel A, Larsson B. Relaxation treatment administered by school nurses to adolescents with recurrent headaches. Headache 2004 Jun;44(6):545-54.
  7. Gavin M, Litt M, Khan A, et al. A prospective, randomized trial of cognitive intervention for postoperative pain. Am Surg 2006 May;72(5):414-8.
  8. Irvin JH, Domar AD, Clark C, et al The effects of relaxation response training on menopausal symptoms. J Psychosom Obstet Gynaecol 1996;17(4):202-207.
  9. Janke J. The effect of relaxation therapy on preterm labor outcomes. J Obstet Gynecol Neonatal Nurs 1999;28(3):255-263.
  10. Larsson B, Carlsson J, Fichtel A, Melin L. Relaxation treatment of adolescent headache sufferers: results from a school-based replication series. Headache 2005 Jun;45(6):692-704.
  11. Medlicott MS, Harris SR. A systematic review of the effectiveness of exercise, manual therapy, electrotherapy, relaxation training, and biofeedback in the management of temporomandibular disorder. Phys Ther 2006 Jul;86(7):955-73.
  12. NIH Technology Assessment Panel on Integration of Behavioral and Relaxation Approaches into the Treatment of Chronic Pain and Insomnia. Integration of behavioral and relaxation approaches into the treatment of chronic pain and insomnia. JAMA 7-24-1996;276(4):313-318.
  13. Siev J, Chambless DL. Specificity of treatment effects: cognitive therapy and relaxation for generalized anxiety and panic disorders. J Consult Clin Psychol 2007 Aug;75(4):513-22.
  14. ldirim YK, Fadiloglu C. The effect of progressive muscle relaxation training on anxiety levels and quality of life in dialysis patients. EDTNA ERCA J 2006 Apr-Jun;32(2):86-8.
  15. Yu DS, Lee DT, Woo J. Effects of relaxation therapy on psychologic distress and symptom status in older Chinese patients with heart failure. J Psychosom Res 2007 Apr;62(4):427-37.


British epidemiologist Archie Cochrane is regarded as the originator of the Evidence-Based Medicine concept (in the 1950s). And the Cochrane Library is a collection of very high-quality medical databases, which have, at their core, the Cochrane Reviews, systematic reviews and meta-analyses which summarize and interpret the results of well-conducted, randomized controlled trials… the ‘gold standard’ in Evidence-Based Medicine.

The Cochrane Library is a subscription-based database but offers free access to abstracts.


A service of the U.S. National Library of Medicine, PubMed was released in 1996 as a free digital archive of references and abstracts on life sciences and biomedical topics. PubMed comprises 20-million-plus citations for biomedical literature from MEDLINE, life science journals and online books from around the world. Some 11.5 million articles are listed with their abstract and 3.1 million articles are available in full-text for free.


The TRIP Database, launched in 1997, is a search engine designed to allow clinicians to quickly find answers to their medical questions using the best available evidence. Trip’s founders realized medical professionals were being forced to perform time-consuming searches at multiple websites to get at the most relevant information. So, they designed TRIP as a meta-search engine, allowing users to both simultaneously search thousands of databases, medical publications and resources, as well as easily filter the results: limiting searches to the most stringent, highest-quality medical evidence or expanding them to include results like patient information, news articles, etc.