Isochronic tones work just the same in delta as they do in alpha, theta and beta and they are widely used in the brainwave entrainment community to help people sleep. Like you, I’ve also seen some websites saying they don’t work in delta, but it’s a bit like the game of Chinese Whispers, where someone makes a comment and then after it gets passed around and shared a lot the message gets distorted and appears to be a fact. I don’t know of any scientific reason why they wouldn’t work in delta. I remember some people talking about this on a brainwave entrainment forum many years ago. They were saying they found isochronic tones a bit too abrupt for using to help them sleep and they preferred binaural beats, as they thought they were a more soothing sound. That was just a personal preference shared by a couple of prominent forum members at the time and some people then took that as a fact for everyone. That’s where I think that belief originated from.
Fortunately, the recommendations for exercise in the role of stress management fit with the current health recommendations (12). The proposed physiological adaptations thought to improve the way the body handles stress and recovers from stress can occur with a regular moderate to vigorous aerobic exercise program (12,13,16), such as the recommendations of 150 minutes of moderate-intensity aerobic exercise per week or 75 minutes of vigorous-intensity aerobic exercise per week. If an individual is using exercise as a time-out from stressors, shorter duration activity can serve the purpose, especially when lack of time or fatigue is a concern. Consider an individual who reports significant work-related stress. Breaking the exercise into two 10- to 15-minute sessions, one before work and one at lunch time when possible, can help combat stress throughout the day. Although there is not a lot of research with resistance exercise and stress management, resistance exercise can be used to provide a time-out from one’s stressors. Because resistance training produces different exercise adaptations compared with aerobic exercise, it might not affect the way the body physiologically reacts to stress as aerobic exercise does. However, the acute effect of a time-out to reduce stress can be beneficial. In addition, clients can receive the numerous health benefits associated with resistance training. The resistance exercise prescription for general health benefits of 2 to 3 days of exercise to target all of the major muscle groups performed at a moderate intensity of 8 to 12 repetitions can be recommended.
Writing or talking about the things that prey on you—in a diary, with friends, in a support group or even a home computer file—helps you feel less alone and helpless. One study, published in The Journal of the American Medical Association, looked at people who had either rheumatoid arthritis or asthma— conditions known to be stress-sensitive. One group chronicled in a perfunctory manner the things they did each day. The other group was asked to write daily about what it was like, including fears and pain, to have their disease. What researchers found: People who wrote at length about their feelings had far fewer episodes of their illness.
Research shows that binaural beats can literally drive brain activity into specific brain states (Gamma, Beta, Alpha, Theta or Delta). Without any effort and naturally, you would have your brain activity to synchronize with the binaural beat; it will become organized and coherent, and eventually, the left and right hemispheres of your brain will start to be balanced creating a very unique state called “hemispheric synchronization” (equal frequency and amplitude of the wave forms in both hemispheres). This extraordinary brain state is very powerful and normally unattainable without this kind of stimulation. Through the entrainment of brain waves, binaural beats can influence the brain in a very subtle way, inducing states of relaxation, sleep, meditation, creativity…
Neural oscillations are rhythmic or repetitive electrochemical activity in the brain and central nervous system. Such oscillations can be characterized by their frequency, amplitude and phase. Neural tissue can generate oscillatory activity driven by mechanisms within individual neurons, as well as by interactions between them. They may also adjust frequency to synchronize with the periodic vibration of external acoustic or visual stimuli.