1. Participants
This study included 328 total individuals: 70 individuals in the H group, 117 individuals in the PH group, and 141 individuals in the CD group. In all groups, most participants were female (90.5% of the total). Participants were between 21 and 96 years old and the mean age was 54.2 ± 15.0 years (Table 1). In the CD group, any diseases and the number of individuals who suffered from each are indicated in parentheses. Diseases included hypertension (47), low back pain (28), depression (14), autonomic dysfunction (13), climacteric disorder (13), cancer (10), bronchial asthma (9), and type 2 diabetes mellitus (6), among others.
Table 1
Demographic characteristics of yoga class attendees
Group
|
H
|
PH
|
CD
|
Total
|
Number
|
70
|
117
|
141
|
328
|
Number of females (%)
|
59 (84.3)
|
110 (94.0)
|
128 (91.4)
|
297 (90.5)
|
Age range
|
26 〜 85
|
21 〜 83
|
23 〜 96
|
21 〜 96
|
Mean age
|
54.7 ± 14.3
|
48.5 ± 14.8
|
58.7 ± 13.9
|
54.2 ± 15.0
|
Values are the mean ± standard deviation. The numbers in parenthesis represent the percentage of female participants. |
H: healthy participants; PH: participants in poor health; CD: participants with chronic diseases. |
2. Characteristics Of The Typical Yoga Class
Typically, the yoga classes were held once a week and the duration was 60 to 90 min. Most classes included 5 to 20 participants. The programs differed according to the instructor and week. However, most classes included asanas (regular yoga postures), pranayamas (breathing exercises), meditation, and savasana (corpse pose). These are commonly practiced in every type of yoga class [20]. Characteristics of the programs in these classes included isometric yoga and sukshma vyayama. In some classes, these two were practiced longer than ordinary yoga asanas. Isometric yoga poses are practiced with low impact isometric load with long breathing. As isometric load is applied at the point where joints stop naturally, it does not require a high degree of flexibility or significant stretch. However, it is accompanied with post-isometric muscular relaxation [21, 22]. Therefore, isometric yoga enables muscular relaxation with minimal stretch. This characteristic is helpful for avoiding any adverse musculoskeletal events. Sukshma vyayama consists of fine movements of each joint. It does not require strong muscle contraction or any stretch, but does require continuous attention to proprioception induced by slow movements. Therefore, this type of yoga helps enhance mindful bodily awareness. Thus, in general these programs are aimed at inducing relaxation and enhancing self-awareness rather than improving musculoskeletal fitness. On intervening days without class, participants were encouraged to practice yoga if they could.
3. Effects On Vigor, Fatigue, And Tension-anxiety
To assess the short-term effects of yoga on mood and fatigue, we compared the POMS V, F, and T-A scores before and after practicing yoga on both the 1st and last day (Table 2). The F and T-A scores decreased significantly (P < 0.001) while the V scores increased significantly (P < 0.001) after practicing yoga in both the 1st and last classes in all groups. This suggests that practicing yoga reduced fatigue and tension-anxiety and increased the feeling of energy in all groups even after just one class.
Table 2
Effects of yoga on vigor, fatigue, and tension-anxiety as assessed by the POMS.
Group
|
|
H
|
PH
|
CD
|
|
|
Pre
|
Post
|
|
Pre
|
Post
|
|
Pre
|
Post
|
|
First
|
|
|
|
|
|
|
|
|
|
|
|
V
|
49.6 ± 8.2
|
56.8 ± 10.7
|
***
|
45.9 ± 9.5
|
56.3 ± 10.4
|
***
|
45.5 ± 10.2
|
53.1 ± 11.4
|
***
|
|
F
|
43.4 ± 8.4
|
37.7 ± 5.3
|
***
|
47.6 ± 9.3
|
37.5 ± 4.2
|
***
|
47.9 ± 11.0
|
39.6 ± 5.9
|
***
|
|
T-A
|
43.5 ± 7.4
|
37.0 ± 4.4
|
***
|
46.5 ± 10.0
|
36.6 ± 4.6
|
***
|
49.6 ± 11.5
|
39.0 ± 6.7
|
***
|
Last
|
|
V
|
49.9 ± 7.7
|
58.0 ± 9.1
|
***
|
48.1 ± 11.4
|
57.9 ± 10.7
|
***
|
47.9 ± 9.4
|
57.0 ± 10.4
|
***
|
|
F
|
44.2 ± 9.1
|
37.4 ± 3.7
|
***
|
46.1 ± 9.6
|
37.3 ± 3.9
|
***
|
45.9 ± 10.5
|
38.4 ± 5.3
|
***
|
|
T-A
|
43.2 ± 8.4
|
36.2 ± 4.0
|
***
|
43.8 ± 8.4
|
37.0 ± 4.8
|
***
|
45.7 ± 11.1
|
37.3 ± 5.7
|
***
|
Values are the mean ± standard deviation. |
H: healthy participants (n = 62); PH: participants in poor health (n = 108); CD: participants with chronic diseases (n = 135). Data from participants that had missing values were excluded from analysis. Pre: before practicing yoga; Post: after practicing yoga; First: the first class; Last: the last class that was held after three months; V: vigor; F: fatigue, T-A: tension-anxiety. *** P < 0.001 (Pre vs Post, paired t-test). |
Table 5
Adverse events experienced by participants during yoga practice
|
Group
|
H
|
PH
|
CD
|
Systems
|
Symptoms
|
First
|
Last
|
First
|
Last
|
First
|
Last
|
Eyes and ears
|
Blackout
|
0
|
0
|
0
|
3
|
2
|
1
|
Pruritus of the eye
|
2
|
0
|
1
|
1
|
1
|
2
|
Tinnitus
|
1
|
1
|
2
|
1
|
2
|
2
|
Respiratory
|
Coughing
|
2
|
1
|
3
|
2
|
6
|
8
|
Congested nose
|
1
|
1
|
2
|
3
|
3
|
2
|
Runny nose
|
1
|
3
|
0
|
3
|
6
|
2
|
Sputum production
|
2
|
0
|
2
|
2
|
0
|
3
|
Cardiovascular
|
Chest pain
|
0
|
0
|
0
|
0
|
1
|
0
|
Palpitation
|
2
|
0
|
1
|
3
|
3
|
1
|
Breathlessness
|
0
|
0
|
0
|
1
|
3
|
1
|
Gastrointestinal
|
Nausea
|
1
|
2
|
0
|
0
|
2
|
0
|
Epigastric and abdominal pain
|
0
|
0
|
2
|
1
|
2
|
3
|
Diarrhea
|
0
|
0
|
0
|
0
|
1
|
0
|
Musculoskeletal
|
Joint pain
|
2
|
1
|
7
|
3
|
8
|
11
|
Muscular pain
|
3
|
0
|
5
|
8
|
9
|
17
|
Skin
|
Flushing of the face
|
3
|
1
|
2
|
0
|
3
|
3
|
Excessive perspiration
|
0
|
0
|
2
|
1
|
3
|
1
|
Pruritus of the skin
|
0
|
0
|
0
|
0
|
2
|
2
|
Neurological
|
Headache
|
1
|
2
|
5
|
2
|
2
|
4
|
Heaviness of the head
|
0
|
2
|
1
|
3
|
2
|
0
|
Feeling hot and cold
|
0
|
0
|
4
|
2
|
10
|
2
|
Faintness (daze)
|
4
|
3
|
7
|
4
|
9
|
8
|
Numbness of a certain body part
|
0
|
0
|
5
|
2
|
2
|
1
|
Twitching in a certain body part
|
1
|
2
|
6
|
2
|
5
|
4
|
Dizziness
|
2
|
4
|
6
|
5
|
14
|
5
|
Fatigue
|
Feeling of exhaustion
|
1
|
1
|
3
|
2
|
5
|
3
|
Feeling sick
|
0
|
1
|
0
|
1
|
1
|
0
|
Psychological
|
Tension
|
0
|
0
|
0
|
0
|
4
|
3
|
Confusion
|
0
|
0
|
1
|
0
|
2
|
2
|
Urge to cry
|
0
|
0
|
0
|
0
|
1
|
0
|
Anxiety
|
0
|
0
|
2
|
1
|
2
|
0
|
Irritation
|
0
|
0
|
0
|
0
|
1
|
0
|
Shaking of the body
|
0
|
1
|
0
|
0
|
1
|
0
|
Recollection of bad experiences
|
0
|
0
|
1
|
1
|
4
|
2
|
The number experiencing a symptom
(%)
|
20
|
16
|
39
|
31
|
58
|
51
|
(28.6)
|
(22.9)
|
(33.3)
|
(26.5)
|
(41.1)
|
(36.2)
|
The number of valid responses
|
70
|
117
|
141
|
H: healthy participants (n = 70); PH: participants in poor health (n = 117); CD: participants with chronic diseases (n = 141). Data from participants that had missing values were excluded from analysis. First: the first yoga class; Last: the last yoga class. Symptoms reported by more than 5.0% of participants in each group are shown in bold (First vs Last, paired t-test). |
4. Effects On Perceived Stress
To assess the effects of regular yoga practice for three months on perceived stress, we compared the PSS scores before and three months after attending yoga classes (Fig. 2). The PSS score in the H group did not decrease significantly over the three months. However, the PSS scores in the PH and CD groups were reduced significantly (P < 0.01) after three months and approached the pre-value of the H group. This suggests that perceived stress levels in the PH and CD groups were reduced by practicing yoga for three months, whereas the H group did not show a significant change.
5. Effects On Health-related Quality Of Life
To assess the effects of regular yoga practice for three months on health-related QOL, we compared the SF-8™ subscale scores before (first) and three months after attending the yoga classes (last; Table 3). In the H group, at baseline, all subscale scores were around 50, an average value for the Japanese population, while three subscale scores, GH (general health perception), MH (mental health), and MCS (mental component summary) scores, had increased significantly (P < 0.05, respectively) three months later. In contrast, in the PH and CD groups, all subscale scores were below 50 at baseline. However, all 10 subscale scores increased significantly after three months of yoga practice (P < 0.01 or 0.05) and approached 50. This suggests that the health-related quality of life in the H group was similar to the average Japanese population since the beginning. In contrast, the quality of life in the PH and CD groups was lower than the Japanese average before practicing yoga, and improved such that it approached the Japanese average in all dimensions after practicing yoga for three months.
6. Changes in severity of subjective symptoms in the PH and CD groups
To assess the effects of regular yoga practice on physical or psychological symptoms or discomforts in the PH and CD groups, we compared the severity of symptoms before (first) and three months after attending the yoga classes (last) using the NRS (Table 4). In the PH group, symptoms that were noted by 10 or more participants included easy fatigability (n = 39, 34.2%), shoulder stiffness (n = 35, 30.7%), low back pain (n = 30, 26.3%), coldness in the body (n = 24, 21.1%), headache (n = 15, 13.2%), and insomnia (n = 14, 12.3%). The severity of these symptoms was reduced significantly (P < 0.01) after three months of yoga practice. In the CD group, symptoms that were noted by 10 or more participants included easy fatigability (n = 32, 23.0%), low back pain (n = 26, 18.7%), knee joint pain (n = 19, 13.7%), shoulder stiffness (n = 19, 13.7%), anxiety (n = 18, 12.9%), and insomnia (n = 14, 10.1%). The severity of these symptoms also decreased significantly (P < 0.05 for easy fatigability, knee joint pain and insomnia; P < 0.01 for low back pain, shoulder stiffness, and anxiety) after three months of yoga practice.
7. Adverse Events
Adverse events that occurred during the first and last classes were recorded just after each lesson. Generally, adverse events were more frequent in the PH and CD groups than the H group, and the incidence during the last class was less than during the first class. Among participants in the H, the PH, and the CD groups, any adverse events were reported in 28.6%, 33.3%, and 41.1%, respectively, during the first class and 22.9%, 26.5%, and 36.2%, respectively, during the last class. Adverse events included those affecting any system/category. Symptoms experienced by more than 5.0% of participants included faintness (n = 4, 5.7%) and dizziness (n = 4, 5.7%) in the H group, joint pain (n = 7, 6.0%), muscular pain (n = 8, 6.8%), faintness (n = 7, 6.0%), twitching (n = 6, 5.1%), and dizziness (n = 6, 5.1%) in the PH group, and coughing (n = 8, 5.7%), runny nose (n = 6, 5.1%), joint pain (n = 11, 7.8%), muscular pain (n = 17, 12.1%), feeling hot/cold (n = 10, 7.1%), faintness (n = 9, 6.4%), and dizziness (n = 14, 9.9%) in the CD group. Among symptoms that none of the participants in the H group reported, the PH group experienced 7 symptoms, such as numbness (n = 5, 4.2%), epigastric and abdominal pain, excessive perspiration, anxiety (n = 2, 1.7%, respectively), breathlessness, confusion, and recollection of bad experiences (n = 1, 0.9%, respectively). Among symptoms that none of the participants in the H group reported, the CD group experienced 13 symptoms, such as tension, recollection of bad experiences (n = 4, 2.8%, respectively), breathlessness, epigastric and abdominal pain, excessive perspiration (n = 3, 2.1%, respectively), pruritus, numbness, confusion, anxiety (n = 2, 1.4%, respectively), chest pain, diarrhea, urge to cry, and irritation (n = 1, 0.7%, respectively). These adverse events were mild and there were no serious adverse events that caused a participant to quit practicing yoga or that required medical treatment.
8. Overall Satisfaction And Benefits Of Yoga
To assess overall satisfaction, we asked participants whether yoga was helpful for maintaining and improving their health or not by giving a score from 1 to 5: (1) very good, (2) good, (3) neither good nor bad, (4) bad, or (5) very bad. In all groups, more than 60% of participants answered “very good” and more than 90% of those answered “good or very good”. In the H group, 1.4% of participants answered “bad”. However, no one answered “very bad” in any group (Fig. 2).