Increased thoracic pressure during inspiration promotes the sympathetic nervous activity (SNA) associated with stress and excitation for wakefulness. During inspiration, baroreceptors detect stretching and pressure within the lungs. Reflex responses from changes in intra-thoracic pressures during breathing create these HRV variations, a phenomenon known as respiratory sinus arrhythmia. Heart rate variability (HRV) measures the variation between heartbeat interval lengths caused by a fluctuation in autonomic nervous activity. PSA is associated with increased nutritional absorption, immune responses that support anti-inflammatory benefits, and recovery from exercise. Research suggests that sleep, especially NREM sleep, is one of the most significant contributors to parasympathetic nervous activity (PSA). Taken from Maximising Sleep For Health & Fitness Workshop – Performance Through Heatlh Autonomic Nervous System Function During Sleep It consists of high-frequency, low amplitude waves however, there is also measurable low muscular tension, if any, corresponding with that rapid eye movements.

On to the second phase of sleep, namely REM sleep, the waveform is similar to wakefulness. Stage 3, known as deep sleep, consists of large-amplitude, low-frequency waves call Delta waves. These complexes look like more significant bursts of electrical activity, thought to be associated with the formation of memories and to prevent arousal through habituation of environmental sounds. N2 is distinguishable because it includes the appearance of Sleep Spindles and K Complexes alongside Theta waves. The following stage is N2, dampening down activity in the reticular activating system, rendering people unconscious. Wakefulness and relaxation consist of Alpha waves, and when drifting into stage N1 or deep relaxation, Theta waves occur. Within NREM sleep, three different stages comprising of dominant brainwave forms.

Through the use of EEG, we can see there are two phases of sleep. Scoring sleep stages uses EEG by analysing waveform amplitude and frequencies within the brain by placing electrodes on the head and face areas. We can measure brainwave activity using a technique called Electroencephalogram (EEG). The brain state consists of wave-like formations that contribute to various stages of sleep, with each stage playing a unique role in our health and recovery. We can define Sleep as a brain state, a process or behaviour. Can Music Be Used To Entrain Deep Sleep Brainwaves Improving Sleep Quality, Exercise Recovery, or Cardiac Health? Sleep & Brainwaves

Sounds to increase deep sleep