Theta waves have a frequency between 4 and 7.5 hertz, making them slower than more wakeful alpha but faster than the dreamless slumber of delta. Theta brainwaves are the frequencies of nighttime dreams and REM sleep when the brain goes through bursts of activity and eye movement. People also experience theta waves in a state of light sleep, deep relaxation, during meditation and prayer, and when daydreaming. Theta waves produce an experience of inward wakefulness where we become disengaged from the outside world while engaging in inner activity. At the lower frequencies of theta, sleeping states are experienced, and at the higher range of frequency, awake relaxed states are experienced. 
Alpha: Alpha brainwave patterns are associated with a state of wakeful relaxation. Slower and lower in frequency (between 9-14 hertz), alpha waves are dominant when we’re calm and relaxed, but still alert. Alpha waves are associated with states of meditation (your yoga class probably puts you in an alpha state), and also with our ability to be creative.

You know how movie characters always look themselves in the restroom mirror when faced with a tough situation? Well, giving yourself a quick pep talk in the looking glass can actually help relieve stress. “‘Mirror work‘ is done by looking in a mirror and vocally speaking positive affirmations to yourself with affectionate conviction, to release worry or to improve your self-confidence,” Whitaker says. To relieve stress in the moment, she suggests using a restroom mirror, your car’s rear-view mirror, or even a compact. “Calm your mind by saying encouraging affirmations aloud to yourself, such as, ‘I am excellent at what I do,’ ‘I’ve got this! I am amazing,’ ‘I am an asset to this company,’ or ‘I am awesome!’” she says.
Controlled or pre/post studies of the effects of BWE using auditory or visual stimulation were eligible for inclusion, provided pulses of light or tone were delivered at frequencies hypothesised to have a beneficial effect or in line with a protocol addressing clinical outcomes. Studies were required to report clinical or psychological outcomes (measured using standard methods or as deemed appropriate by peer review) and to report statistical analysis. Studies of outcomes such as electroencephalogram (EEG) response or neurotransmitter levels were not eligible. Case studies were excluded.
The aim of this study is to identify tendencies in the effectiveness of relaxing audio stimuli that could be verified through further focused experiments. A series of brainwave entrainment (BWE) techniques for inducing relaxation will be presented consisting of different binaural phenomena (BP). The BP will derive from the binaural sine wave beat, widely acknowledged in rhythmic BWE... [Show full abstract]
I was raised on a farm, and in my youth I dug enough fence post holes to last a dozen lifetimes. My father used to joke that he gave me that chore so that I’d have lots of practice and get good at digging fence post holes. From a pragmatic point of view, the purpose of digging all those post holes was really not so that I’d become a better post hole digger, but so that I could plant posts in them. Once you dig a post hole to the correct depth you don’t keep on digging, trying to make the hole fancier or more aesthetically pleasing. You stick a post in that sucker, tamp the earth back in around it so that the post is secure, and then move on to dig the next hole.
The exact physiological mechanisms to explain how exercise improves stress have not been delineated. Human and animal research indicates that being physically active improves the way the body handles stress because of changes in the hormone responses, and that exercise affects neurotransmitters in the brain such as dopamine and serotonin that affect mood and behaviors (9,11). In addition to the possible physiological mechanisms, there also is the possibility that exercise serves as a time-out or break from one’s stressors. A study that tested the time-out hypothesis used a protocol that had participants exercise but did not allow a break from stress during the exercise session (5). Participants were college-aged women who reported that studying was their biggest stressor. Self-report of stress and anxiety symptoms was assessed with a standard questionnaire before and after four conditions over 4 days. The conditions were quiet rest, study, exercise, and studying while exercising. These conditions were counterbalanced across participants, and each condition was 40 minutes in duration. The “exercise only” condition had the greatest calming effect (5). When participants were not given a break from their stressor in the “studying while exercising” condition, exercise did not have the same calming effect.

, that is, the average of the two frequencies. It can be noted that every second burst in the modulation pattern is inverted. Each peak is replaced by a trough and vice versa. However, because the human ear is not sensitive to the phase of a sound, only its amplitude or intensity, only the magnitude of the envelope is heard. Therefore, subjectively, the frequency of the envelope seems to have twice the frequency of the modulating cosine, which means the audible beat frequency is:[5]
So, what we’re doing is combining these two parts, the awakening of complete stillness and deep relaxation with the rhythmic sounds, and embedding all frequencies within the music from right at the upper limits of human hearing to the lower limits. There is multi-level entrainment within Journey—I’ve layered in everything I know about audio brainwave entrainment into this track. 

Changes in neural oscillations, demonstrable through electroencephalogram (EEG) measurements, are precipitated by listening to music,[20][21][22][23][24][25] which can modulate autonomic arousal ergotropically and trophotropically, increasing and decreasing arousal respectively.[26] Musical auditory stimulation has also been demonstrated to improve immune function, facilitate relaxation, improve mood, and contribute to the alleviation of stress.[27][28][29][30][31][32][27][33] These findings have contributed to the development of neurologic music therapy, which uses music and song as an active and receptive intervention, to contribute to the treatment and management of disorders characterized by impairment to parts of the brain and central nervous system, including stroke, traumatic brain injury, Parkinson's disease, Huntington's disease, cerebral palsy, Alzheimer's disease, and autism.[34][35][36]