Theta waves also have been observed in moments when a person recalls information from the past, and this may be what links them also to improvement in learning ability. We also experience theta waves when we go into automatic pilot mode, such as when doing a repetitive task like driving a familiar route where the mind become disconnected while you still drive safely toward your destination.
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)
When tuning instruments that can produce sustained tones, beats can be readily recognized. Tuning two tones to a unison will present a peculiar effect: when the two tones are close in pitch but not identical, the difference in frequency generates the beating. The volume varies like in a tremolo as the sounds alternately interfere constructively and destructively. As the two tones gradually approach unison, the beating slows down and may become so slow as to be imperceptible. As the two tones get further apart, their beat frequency starts to approach the range of human pitch perception[1], the beating starts to sound like a note, and a combination tone is produced. This combination tone can also be referred to as a missing fundamental, as the beat frequency of any two tones is equivalent to the frequency of their implied fundamental frequency.

In 1984 medical researcher Dr. Gene W. Brockopp published a paper making several conclusions of audio and visual entrainment (AVE). Such conclusions were that hemispheric synchronization caused by AVE is related to increased intellectual functioning, practiced use of AVE overtime leads to a cumulative effect, and AVE may result in the recovery of early childhood experiences.

... One of the possible explanation for insignificant results could be length of exposure to AVS. Our participants were exposed to it for 11 minutes, while some authors (Cruceanu & Rotarescu, 2013) suggest that at least 20 minutes is needed for the positive effects to take place. Furthermore, part of our reserach was also visualization of gymnastic skills, performed after AVS. ...
Let’s face it, the stress we face today isn’t going anywhere, which is exactly why it’s more important than ever to find natural ways to bust stress that work well for us. If you’re up against large amounts of stress in your life (and who isn’t?), studies show you can greatly benefit from carving out more time in your busy schedule for things like regular exercise, meditation, spending time outdoors and keeping up with fun hobbies.
In a recent national survey, 44 percent of adults said stress had caused sleepless nights at least once in the previous month. All that tossing, turning and staring at the ceiling can leave you feeling tired and more stressed the next day. If you’re caught in this vicious cycle of anxiety and insomnia, there’s good news: Simple stress relief techniques can help you sleep better and feel calmer.
CBT focuses on challenging and changing your thoughts first and foremost, since the way you perceive an event (not the actual event itself) means everything in terms of how your body reacts. (10) Once you can identify the root thought pattern that is causing harmful behaviors, you can work on changing how you think about events and therefore react to them.
You have three Theta options. First, you can begin with the 30 minute Alpha Light Meditation, then do the 30 minute Theta Deep meditation that is in the same folder with the Alpha track. This is the most gentle way to introduce yourself to the Theta meditations, as these two tracks are designed to work with each other. This Theta track must be used after the Alpha track, because it begins with the same frequency where Alpha ends.
However, very experienced practitioners of meditation are able to enter a Delta state and maintain consciousness at the same time. Yoga nidra or “yogi sleep” is a sleep-like state which yogis report during their meditations. This lucid sleeping state is among the deepest possible states of relaxation while still maintaining full consciousness (“super-conscious mind”). In this state, experienced yogis are able to regulate their body temperature and heart rate.
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. 
CBT focuses on challenging and changing your thoughts first and foremost, since the way you perceive an event (not the actual event itself) means everything in terms of how your body reacts. (10) Once you can identify the root thought pattern that is causing harmful behaviors, you can work on changing how you think about events and therefore react to them.

Literally embrace whatever it is you're going through and then let it go. Try doing a tai chi exercise known as "embracing the tiger," where you take your arms, spread them wide, put your hands together and then draw them—and everything around you—toward your navel, the center of your being. Doing this allows you to take the good with the bad. Then reverse your hands and push them out, releasing your tension. When you can control stress, it can no longer control you. (Follow it with this progressive muscle relaxation technique to reduce stress.)
Move your focus to the sole of your right foot. Tune in to any sensations you feel in that part of your body and imagine each breath flowing from the sole of your foot. After one or two minutes, move your focus to your right ankle and repeat. Move to your calf, knee, thigh, hip, and then repeat the sequence for your left leg. From there, move up the torso, through the lower back and abdomen, the upper back and chest, and the shoulders. Pay close attention to any area of the body that causes you pain or discomfort.
It is important to note that not all stress is bad. Everyone experiences a certain amount of stress on an almost daily basis, and it cannot be completely eliminated. Stress becomes a problem when too much is experienced, and it has a negative impact on behaviors, relationships, and health. The term “eustress” refers to positive stress that is associated with improved performance and productivity. “Distress” is negative stress that is associated with performance decrement and negative health consequences. The individual’s perception of the stressor and coping resources determine whether a situation is eustress or distress. College graduation is a stressor for most. The student who has a job or who has been accepted to a graduate program likely perceives the stress of graduation as eustress, whereas the student who has student loans and no immediate plans of a job or further education perceives distress.

In addition to understanding how exercise can help manage stress and the types of exercise to recommend for stress management, it is important to understand common barriers that might affect exercise participation in high-stress clients. Lack of time is the most commonly reported exercise barrier for individuals in general. A lack of motivation, fatigue, poor sleep habits, and poor dietary habits are factors associated with stress that can negatively impact exercise compliance and adherence (4). Common exercise barriers and stress-related health problems should be taken into consideration when developing an exercise prescription for high-stress individuals.

This is not to say that entrainment cannot produce some physical effects, particularly negative ones. It is possible to induce epileptic seizures using entrainment, especially visual entrainment that employs flashing lights. That’s why people with seizure disorders are uniformly told to consult with their health care provider before using entrainment if they have a seizure disorder or some other serious medical condition.
All brainwave frequencies are useful and beneficial at certain times – there is no brainwave that is intrinsically better than another. However, by deliberately choosing to attain a particular brainwave state, a corresponding mental state can be brought about at the same time. For example, a working person who has been in an overly alert beta brainwave pattern for many hours can quickly shift their mind and body into a relaxed state by listening to a few minutes of brainwave entrainment music for inducing alpha or theta brainwaves.
“When you play two separate frequencies in each ear, say 140 Hz and 149 Hz, the difference in frequency is 9 Hz. Your brain compensates for this difference, and a third tone of 9 Hz is experienced,” says Niraj Naik, founder of Trpynaural, a resource for binaural tracks. “This will result in your brain being raised or lowered and tuned into the desired frequency. This is how binaural beats are produced.”
I have seen 1.5Hz being linked to HGH, but also 4 or 5 other frequencies as well, so it’s difficult to know what may work if any. I haven’t seen any research relating to HGH and brainwave entrainment. It’s widely believed that 40Hz is the limit for achieving a brainwave entrainment effect, which is also where many believe the gamma frequency range begins. Once you get over 40Hz into gamma your brainwave activity isn’t likely to stay in sync with it. So from a brainwave entrainment perspective, I recommend high beta frequencies for increasing energy during workouts.
^ Trost W. and Vuilleumier P., Rhythmic entrainment as a mechanism for emotion induction by music: a neurophysiological perspective. In The Emotional Power of Music: Multidisciplinary Perspectives on Musical Arousal, Expression, and Social Control, Cochrane T., Fantini B., and Scherer K. R., (Eds.), Oxford, UK: Oxford University Press; 2013, pp213–225.