Study of Effectiveness of Audio Guided Deep Breathing on Improving the Quality of Life of Physically Disabled Group

Background:

Diaphragmatic breathing is also known as deep breathing as the breathing process is always associated with belly expansion, diaphragm contraction, and deep inhalation and exhalation which results in greater intake of blood gases and reduced respiratory frequency that is in contrast to the normal breathing cycle. Some of the studies revealed the potentiality of deep breathing in enhancing social adaption, emotional balance, stress management and physiological stability. The advantages of deep breathing also have been reported extensively in ancient eastern religions, including yoga, meditation and Tai Chi Chuan (TCC). The positive outcomes of deep breathing have evoked scientific interest in the investigation of the causal relationship between deep breathing practice and physiological behaviours. Since deep breathing is voluntary respiration which is opposed to natural breathing, it will give rise to certain degrees of physiological changes unavoidably. Physiological changes including tidal volume, heart rate variability, electroencephalography and hair cortisol level have been reported in the previous works of literature.

Literature Review:

Effect of Deep Breathing on Pulmonary Function

To achieve optimal oxygen saturation level, tidal volume and respiratory rate are the two primary components of respiratory measurement responsible for the purpose. Tidal volume is the amount of air-filled in each breathing cycle. Under relaxed conditions, these two parameters change interchangeably to optimize oxygen intake. Since deep breathing is involuntary breathing, it inevitably brings changes to the pulmonary parameters. For example, some researchers found out that tidal volume and other pulmonary parameters such as forced expiratory volume and forced vital capacity increased after ten minutes of deep breathing compared to normal chest breathing. Some authors also agreed that the deep breathing technique showed improvement in pulmonary function in a healthy subject.

Effect of Deep Breathing on Heart Rate Variability

Heart Rate Variability (HRV) is modulated by autonomic nervous system and further divided into two branches: sympathetic and parasympathetic pathways. The sympathetic nervous system is concerned with critical events such as respiratory failure and survival challenges that causes blood pressure and heart rate to increase. This is known as the "fight-or-flight" reaction. In contrast, the parasympathetic nervous system focuses on the resting and conservation of energy that acts in opposition to the sympathetic pathway. They work together dynamically giving rise to HRV and serving as a measurable index of autonomic control. It was reported that breathing can influence cardiopulmonary function that indirectly reflects HRV. Inhalation and exhalation alter the heart rate which is known as respiratory sinus arrhythmia (RSA). In other words, inhalation reduces R-R intervals in electrocardiogram (ECG) and increases during exhalation. Slow and deep breathing which has lower respiratory frequency is found to augment cardiorespiratory synchronization and elevate HRV. Most of the studies reported that slow and deep breathing can bring positive effects to HRV that is associated with stress, diabetes mellitus and rheumatoid arthritis.

The analysis of HRV can be divided into time-domain and frequency-domain analyses. In frequency-domain analysis, there are high-frequency spectrum (HF) (0.14 Hz - 0.40 Hz) and low-frequency spectrum (LF) (0.04 Hz - 0.15 Hz) that refer to parasympathetic and sympathetic activities respectively. On the other hand, time-domain analysis, for instance, root mean square of the variation in R-R interval (RMSSD), N-N interval standard deviation (SDNN) and average R-R intervals standard deviation (SDANN) are begin measured as the units.

One of the studies suggested that LF increased at once after five minutes of deep breathing whereas SDNN and RMSSD changes are insignificant. Conversely, a pilot study on the impact of different deep breathing duration reported showed that normalized HF power is smaller than the control group without deep breathing. This study suggested that depression score is lower in the deep breathing groups with lower HF reading. The difference is due to the sympathetic activation being involved when a novel and short exercise was provided whereas long training will shift to parasympathetic activation. Another research also suggested that SDNN increased after deep breathing indicating stress relief.

Effect of Deep Breathing on Electroencephalography (EEG)

Electroencephalography (EEG) is a well-known screening technique to acquire the scalp electrical behaviour of the brain. The electrical activity is a product of neuron activation in the brain that causes a flow of current. During the event of synaptic activation in the cerebral cortex, the current flow is the one captured by EEG. There have been numerous studies to investigate the application of EEG in neurology and neuropsychology studies due to its strong ability in receiving neurofeedback from the brain from the past until now.

The brainwave is classified into four mainly by the amplitude and frequency differences. Alpha waves (8 - 13 Hz) is associated with the mental task, awake or resting that is recorded in the parieto-occipital area. Next, beta waves (14 - 30 Hz) is gathered during mental activity similarly which is presented in the parietal or frontal region while theta waves (4 - 7 Hz) is found when an adult is sleeping or drowsy but it also indicates stress when the adult is waked. The last wave is delta waves (< 3.5 Hz) which shows that an adult is in deep sleep or severe brain damage in waked adult.

These brainwaves are shown to correlate with deep breathing. Alpha wave is associated with relaxation and stability while beta wave shows certain degrees of stress and stimulation. For example, it was suggested that slow and deep breathing elevated alpha to the high beta ratio which indicates improvement of mental stability. Similarly, deep breathing, as an important element in mediation and yoga practice also has proposed that it increased alpha power in prior studies. On the other hand, some studies showed that beta activity decreased after slow and deep breathing but some studies oppose the findings. Previous research projects have documented that frontal theta power increased is associated with reduced anxiety as well.

Effect of Deep Breathing on Cortisol Level

In the event of the stress response, a cascade reaction of hormone occurs at the pituitary gland, hypothalamus and adrenal gland. Glucocorticoids is a compound as a result of the stimulation play an important role in stress coping that could activate a series of physiological responses such as immune activation, inflammatory suppression, reproductive physiology reduction and energy mobilization. Hair cortisol analysis is a relatively novel technique compared to saliva and urine cortisol analysis. Although the mechanism of cortisol deposition is pending further investigation, it is a promising technique with more benefits. It is non-invasive, unlikely to be affected by sampling procedures, lower storage requirement and cortisol production measured has a longer timeframe (months to years). Therefore, it is considered a good biomarker of chronic stress level that has driven several studies such as antenatal stress, relaxation interventions, early childhood and neonates.

Deep breathing has been shown to reduce cortisol levels which were reported by previous studies. However, they were using saliva and plasma for the assessment respectively. Similarly, some authors have provided evidence of interventions that are incorporated with deep breathing reported to reduce cortisol levels as well. For example, it was suggested that laughter yoga that involved deep breathing as one of the components has shown a reduction in salivary cortisol levels. For hair cortisol assessment, one study used this technique that stress reduction program with deep breathing component proved that cortisol level was reduced. The relationship between hair cortisol and deep breathing intervention is rarely analyzed in the previous studies. A closer look at the literature on intervention incorporated with a deep breathing exercise, however, reveals a question of whether deep breathing alone was contributing to the reduction of hair cortisol. Therefore, this was an important question to study the effect of deep breathing exercise itself on hair cortisol levels.