Brainwaves, or neural oscillations, share the fundamental constituents with acoustic and optical waves, including frequency, amplitude and periodicity. Consequently, Huygens' discovery precipitated inquiry[citation needed] into whether or not the synchronous electrical activity of cortical neural ensembles might not only alter in response to external acoustic or optical stimuli but also entrain or synchronize their frequency to that of a specific stimulus.[16][17][18][19]
“Stress” is a commonly used term, and it is often used with different meanings. The standard definition for stress that will be used in this article is the disruption of the body’s homeostasis or a state of disharmony in response to a real or perceived threat or challenge (8). The threatening or challenging situation is referred to as a “stressor.” When a person encounters a stressor, the body prepares to respond to the challenge or threat. The autonomic nervous and endocrine systems respond by producing the hormones epinephrine, norepinephrine, and cortisol. The result of this hormone production is a cascade of physiological reactions that make up the stress response. Epinephrine and norepinephrine are involved in the initial changes that take place to prepare the body to react and to prepare for a challenge. These responses include increases in heart and respiration rates, blood pressure, perspiration, and energy production (8). There also is a suppression of immune function, production of β-endorphin (the body’s natural pain killer), and increased acuity of the senses. These changes make up the fight-or-flight response, which prepares the body to cope with the stressor. If the stressor is perceived as negative or more as a threat than as a challenge, cortisol production is increased. Cortisol is involved in energy production but also suppresses immune function.
I have read something different about theta waves and learning languages. A University of Washington study tested students resting brainwave activity before learning French. They found that students with a higher amount beta/gamma and a lower amount of delta/theta activity were better at acquiring a second language. When you are dominant in theta, that is the lowest and most deeply relaxed awakened state you can be in. I think it would be much harder to really concentrate, fully understand and learn new information while in a theta state, so I would personally consider using theta while studying.
Maya Mendoza is a published author of 3 personal development books. She has run an NLP / EFT Practice for 29 years helping clients transform problems into personal power. Maya is also a accomplished copywriter and well known Digital Marketing & Social Social Media Strategist - Specializing in Google+ for business. She was named "best marketing consultant" in Glasgow, UK in 2013.  
In the average person, the activity of one brain hemisphere is dominant over the other, called brain lateralization. This hemispheric imbalance leads us to experience the world in a black and white way, perceiving separation over connectedness. When brainwave entrainment is used to synchronize brainwave activity in both hemispheres simultaneously, a person can more easily integrate information from all parts of the brain and solve problems with greater intelligence and sensitivity.
There’s a growing body of research suggesting that binaural beats can reduce different forms of anxiety, from mild to chronic. One especially interesting study looked at the effects of binaural beats on anxiety among patients preparing to undergo surgery—a life circumstance that is pretty anxiety provoking for most anyone. Over a period of six months, patients spent 30 minutes on the day of their surgery listening to binaural beats. Compared to patients who listened to a soundtrack that did not include binaural beats—and patients who received no “beats” therapy at all—the binaural beat listeners experienced significantly greater reductions in their anxiety levels.
4. Be hesitant committing to any BWE system making wild claims. Profit fueled marketers with little to no experience in the BWE field have created a slew of low-quality entrainment systems on the market. These products typically make outrageous promises such as permanently enhancing the brain within minutes of use. Although BWE is a powerful method to improve the mind, it’s not a magic bullet.
Once you begin to experience the beneficial aspects of brainwave entrainment, you may be tempted to have these tracks playing all the time during your waking and sleeping hours. This is NOT advisable, nor is it necessary. Remember, brainwave entrainment is exercise for your brain so your brain will need to rest and integrate the new changes that your entrainment regime is creating.
A crossover RCT of a single session of theta stimulation in four healthy adults reported no significant improvement in verbal fluency or attention associated with the intervention and a reduction in immediate recall. Controlled comparisons reported significant benefit from the intervention in all three outcomes measured. Six pre/post studies reported significant benefit from the intervention for 19 of 28 cognitive outcomes.
From a strictly physical/emotional viewpoint, the benefits of meditation include (but are not limited to) such things as greater resistance to stress; less physical illness and improved resilience when illness does occur; better quality of sleep and increased recovery during sleep; a generally magnified sense of well-being; a sharper, clearer mind; increased capacity for learning; improved functioning in daily life; more harmonious relationships; greater control over emotional states, and more.
The buyer / downloader of the royalty free brainwave entrainment music / downloads on this site assumes all risks in using the music, waving any claims against the owners of Royalty Free Meditation, its affiliates and its parent company, Spire Audio, for any and all mental or physical injuries. This includes all self-created suggestions for mood altering, brain wave states altering, and for self-improvement or motivation. The buyer/user also agrees to assume liabilities when other persons have access to the Binaural beats or any music / downloads and/or anything it produces, including WAV, MP3, files or CDs, whether for commercial or private use. In no case will Enlightened, its affiliates and its parent company, Spire Audio, be liable for chance, accidental, special, direct or indirect damages resulting from the use or misuse of our music.

Although there is a general stress response pattern, there can be variations in the response according to the characteristics of the stressor (10). Individuals tend to respond differently based on the familiarity of the stressor. For example, the perceived level of stress and physiological response when giving a presentation to a group of work colleagues will likely be less than when presenting to an unfamiliar group. The stress response also varies depending on the level of perceived control one has over the stressor (10). If there is a way for one to actively cope with the stressor that is reasonable, then the individual usually perceives more control over the situation. Consider an individual who has to take a certification examination for work and has 6 months to prepare. He can adjust his schedule to accommodate study time. However, waiting for medical test results that show whether one has a serious illness does not allow a sense of control over the stressor, and the individual passively endures the stressor or may try to avoid the stressor. With this uncontrollable type of stressor, there is a more negative reaction with greater productions of cortisol, which can have damaging health effects because of the suppression of immune function (10).
... [9] While entrainment by binaural auditory beats in the alpha frequency has also been shown to enhance creativity, cognition, memory, and an improvement in intelligence tests and achievement tests in learning disabled boys. [10][11][12][13] The gamma-band activity has been shown to involve in a variety of functions such as attention, memory, and consciousness. Current literature suggests that entrainment by gamma beats promotes cognitive flexibility, modulates visual attention, and enhances creativity. ...
Binaural beats are the playing of two sine waves of close, but not the same, frequency into different earpieces of a set of headphones. The "beat" is heard as the brain tries to process them as a distinct sound, while taking into account the constructive/destructive interference. It is said to migrate brain waves to be closer to that frequency, like a sort of biological resonance, which is true. Of course the same can be said for listening to relaxing music help you relax, up tempo music to help you feel energetic, etc...

Our brainwave states are natural. Guiding the brain into those states intentionally by using entrainment is just another way of experiencing those same natural states. Nothing “unnatural” is produced by the brain as a result of using entrainment. The only thing that is different is that when using entrainment we often go into the experience with either general expectations, or a well defined laundry list of specific expectations that we associate with entrainment. We have no such list going throughout our normal day when we’re not using entrainment.
Everyone experiences stress, and not all stress is bad. However, individuals who experience acute episodic and chronic stress are at increased risk for developing stress-related health problems. This article outlines the relationship between stress and health and discusses the role of exercise in managing stress. Exercise recommendations and stress management tips are provided.
Binaural beats are pretty simple. Basically, you take two frequencies that are similar and play each one through it’s own stereo headphone. The two competing frequencies will work together in your mind to produce a pulsing. That pulse will be a certain frequency that corresponds to a number in hertz that is linked to what your brain produces when you are in certain states of consciousness.

When two pure tones of slightly different frequencies are delivered simultaneously to the two ears, is generated a beat whose frequency corresponds to the frequency difference between them. That beat is known as acoustic beat. If these two tones are presented one to each ear, they still produce the sensation of the same beat, although no physical combination of the tones occurs outside the... [Show full abstract]
While the physiological and psychological processes being uncovered by brain science in the study of brainwaves is sometimes complex and still being investigated, certain basic principles are well-established, easily understood, and helpful for achieving the most effectively use of brainwave entrainment when seeking relaxation, improved sleep, lowering of anxiety, or other goals. This important background information and scientific knowledge presented here includes: 
In 1973, biophysicist Dr. Gerald Oster published a famous article in Scientific American titled “Auditory Beats in the Brain”, which found that when two pure tones of varying frequencies were combined, a third rhythmic beat was created which he called binaural or monaural beats. According to Oster, monaural beats occur when two tones are combined and sent through a loudspeaker, while binaural beats occur when stereo headphones are used to deliver each tone separately to each ear. Oster concluded that monaural beats were a more effective form of brainwave entrainment.
In addition to potentially boosting sleep-promoting hormones, binaural beats may also reduce our perceptions of pain. A 2017 study found binaural beats used in combination with visual stimulation led to reductions in patients’ perception of acute pain. Other recent research showed binaural beats helped improve pain perception in patients with chronic pain.
A study published in Electroencephalography and Clinical Neurophysiology by Paul Williams and Michael West in 1975 examined the brainwave states of people experienced in meditation while using photic stimulation, and another study by Leonard, Telch, and Harrington in 1999 examined the successful use of brainwave entrainment techniques for attaining meditative states in subjects.
Brainwave entrainment is a field of study and endeavor founded in the same physiological and psychological processes that make music, drumming, and chanting so powerful as methods for transforming the mind and spirit and aiding in healing of the body. These processes involve how the electrical energy in our brains synchronizes with sounds and visual stimuli, producing a particular brainwave frequency and its associated mental states. 
The effects are strongest while you are listening to the tones because your brainwaves are synchronized and tuned into the frequency range you desire at that time.  After you've stopped listening the effects can still linger for a while afterwards.  The timescale will vary from person to person and be affected by what you do after you've stopped listening.
Hi Rona, thanks for your compliments on my videos and the music I use, I’m pleased you’ve found them helpful. Regarding the pulse-like sound you’ve been hearing, I’ve never had anyone report something similar to that before. I also haven’t heard anyone on brainwave entrainment forums mention it. That is very unusual and because I’ve never come across it before, I’m afraid I don’t know what would cause that.
It is common for people to try entrainment thinking it is going to produce meditation just because they listened to a track. Often they come away disappointed, feeling that nothing special happened. They decide entrainment isn’t what they were led to believe it was. Or they decide meditation is vastly overrated and for them at least, ineffectual. Their disappointment has more to do with not understanding the principles listed thus far than it does with the effectiveness of meditation and brainwave entrainment.
When the track is over you can continue to meditate without the help of the entrainment track.  When you are ready to get up, thank your Higher Self for the experience and remove your blindfold, keeping your eyes closed.  Stay seated with your eyes closed for a few moments, then slowly open them and take a moment to let your eyes adjust to your environment’s light. 
Acupuncture has increasingly been used to treat many stress-related conditions, including psychiatric disorders, autoimmune or immunological-related diseases, infertility, anxiety, and depression. Researchers have found that acupunture treatments result in changes in the cardiovascular and immune systems, increasing protective T-cell proliferation and helping with cellular immuno-responses. (8)
Because the brain filters and interprets reality in a split-brained way, we tend to see things as separate and opposed, rather than as connected and part of the oneness spoken of by the great spiritual teachers (and, in the last few decades, by quantum mechanical physicists). Thus, at a deep level, the dual structure of our brain, in conjunction with brain lateralization, predisposes us to see and experience ourselves as separate from, and often in opposition to, the rest of the world—instead of experiencing the elegant interconnectedness between us and everything else. Our childhood associations and programming build on this inborn tendency by training us to seek this and avoid that, to move toward pleasure and away from pain, to do good and not bad, and so on. The greater the lateralization in the brain, the greater the feelings of separation—and the greater the feelings of separation, the greater the fear, stress, anxiety, and isolation.
Most wisdom traditions have employed methods that allow the subjects' brain waves to slow down such as meditation, [Hindu] kirtan, [Gregorian, Menzuma or Sufi] chanting, Hebrew davening, Native American drum circles and rain chants, Tibetan prayer bowls, and whirling dervishes and African trance dancing. The rhythm of these wisdom tradition technologies actually slows people's brain waves from their normal busy brain frequency we call Beta (13-30 cycles per second or Hz), to Alpha (8-13Hz) -- meditation, Theta (4-8Hz) -- deep relaxation and dreaming, and Delta (.5-4Hz) -- slow wave or dreamless sleep.
Cognitive behavioral therapy (CBT) is a type of therapeutic practice that has been proven to lower anxiety, stress and multiple disorders — including addiction, eating disorders, insomnia and depression. Knowing that at least 50 percent of the time experiencing a mental disorder is due mostly to chronic, untreated stress reactions, therapists use CBT to train all types of people to better react to situations that are stressful.
One RCT (n=108) showed significant reduction in anxiety from a single session of alpha/delta therapy for day surgery patients. A crossover RCT of a single session of theta stimulation in four healthy adults reported significant improvement from the intervention in one of five measures. Five pre/post studies reported significant benefit from the intervention for 16 of 27 outcomes.