The present results indicated that in the selected yoga exercises group, there is a significant difference between the three measurement stages in terms of the depression variable in such a way that the depression levels in the post-test and follow-up stages were less compared to the pre-test one. Several researches have been conducted in this field which are consistent or inconsistent with the present study. Naveen et al (2016), Yoshihara et al (2014), Telles et al (2015), Devi et al (2015) and Schuver and Lewis (2016) The results of all the mentioned researches are in line with those of the present research [32, 16, 33, 17, 18].
The effect of yoga on depression
Yoga affect the body and mind by changing the internal environment which control nervous system ultimately affecting sympathetic, parasympathetic system, release of neurotransmitters, hormonal outflow, mind and brain functioning, thought process i.e. affect the whole homeostasis of body. So it has very diverse effect on the body and mind physiology . One of the physiological hypotheses about the causes of depression is the monoamine hypothesis. This hypothesis states that an imbalance in dopamine (a neurotransmitter related to the reward and pleasure) and serotonin (neurotransmitter related to happiness) causes depression. The recent positron emission tomography studies indicate that yoga exercises increase the dopamine levels in the striatum by 65% . In addition, the regular yoga exercise leads to an increment in the serotonin level along with a decrease in the monoamine oxidase one and improves the mood and state of well-being . Another cause of depression is associated with the decreased neural balance in the hippocampus and hypothalamic-pituitary-adrenal axis . Brain-derived neurotrophic factor (BDNF) is an available factor in most tissues which is produced in the hippocampus and cortex and found in the blood [38, 39]. Clinical studies focusing on the BDNF measurement in the blood, have reported lower levels of this factor in patients with depression . Yoga exercises may act as a powerful stimulant for the hypothalamic-pituitary-adrenal and noradrenergic systems and reduce depression by reducing the cortisol and increasing BDNF . Dalgas et al (2008) concluded that the yoga exercises control the mind and central nervous system by nature, which, unlike other exercises, has a moderating effect on the functioning of the internal nervous system, secretion of internal hormones, physiological factors, regulation of nervous messages, etc . According to this viewpoint, in addition to music, yoga, exercise, study and meditation also leads to the happiness and relaxation and thus reduces the depression . On the other hand, increasing brain activity improves the concentration and social relationships and consequently the depression reduction .
In fact, yoga practice techniques both exercise the body and stimulate the mind. Yoga helps one in increasing adaptation by reducing stress and brings body and mind relaxation through limiting the stress and reducing arousal of the cerebral cortex and thus reduces anxiety and depression . However, Oken et al (2004) arrived at results being inconsistent with the present achievements . However, this inconsistency might be related to the type of selected yoga exercises that focus only on physical exercises, as well as the intensity of the practices and the stress induced by the research conditions.
The effect of massage on depression
The present results further indicated that in the massage group, there is a significant difference between the three stages of depression measurement in such a way that the depression levels in the post-test and follow-up stages were less compared to the pre-test one.
On the effect of massage therapy on depression, Hassan et al (2019), Alves et al (2017), Zadkhosh et al (2015), Field et al (2012) and Imanishi et al (2009) examined the influence of massage therapy on the depression in patients with cardiac catheterization, cancer patients, adolescent wrestlers, pregnant women and patients with breast cancer, respectively. They also mentioned the positive effect of massage therapy on reducing the depression. The results of these studies are consistent with the present achievements in terms of the effect of massage on the depression. massage reduces the secretion amount of cortisol hormone in the body and depression as a consequence [46, 47]. However, some researchers have not found any significant difference between the depression rates of patients before and after the massage therapy intervention [26, 27]. Coelho et al (2008) illustrated in a review study that there is incomplete evidence to testify this . However, the discrepancies between the results of the above-mentioned studies and the present research might be due to the type of massage therapy protocol.
Other results of the present study illustrated that the rate of depression associated with the massage/yoga combination group at the post-test and follow-up stages decreases compared to that of the pre-test one. To the best of the present authors’ knowledge, no study has concerned with examining the effect of a combination of massage and yoga on the depression level in elders. Further to these, the present results indicated that there is a significant difference between the pre-test and follow-up stages of the massage, yoga and massage/yoga combination groups in terms of the depression variable. The reason for the durability of the physiological and mental effects of these protocols is attributed to the massage executive protocol, nature of breathing and relaxation exercises of yoga, conditions and duration of the programs.
Finally, the present results indicated that there is a significant difference between the four groups of massage, yoga, massage/yoga combination and control in terms of the depression variable. There was also significant differences between the experimental groups separately and the control one and also between the yoga and massage/yoga combination groups. Also, comparing the three experimental groups, the combinative, massage therapy and selected yoga exercise protocols, had the most to the least effects in improving the depression in the elders, respectively. In this regard, no research has been found to compare these three treatment methods for the depression.