Authors and Affiliations:
Authors: Mayumi Hirosaki, Tetsuya Ohira, Yawei Wu, Eri Eguchi, Kokoro Shirai, Hironori Imano, Narumi Funakubo, Hitoshi Nishizawa, Naoto Katakami, Iichiro Shimomura, and Hiroyasu Iso.

Institutions:
Fukushima Medical University, Japan.
Kyoto University, Japan.
Osaka University, Japan.
Published: March 31, 2023.
Journal: Frontiers in Endocrinology.

Background:Type 2 diabetes is a chronic condition requiring lifelong management through medication, diet, and exercise.
Studies show 40–60% of diabetic patients worldwide fail to maintain good glucose control (HbA1c < 7%).
Psychological stress often leads to poor adherence to diabetes management routines.
Positive emotions like laughter improve adherence, reduce stress, and improve glucose metabolism.

Why Laughter Yoga?
Unlike other exercises, Laughter Yoga is enjoyable and motivating, making it easier for people to stick to routines.
Previous research suggested laughter reduces post-meal glucose spikes, but long-term studies were lacking.

Objectives:
To test whether Laughter Yoga improves HbA1c (blood sugar) levels.
To measure its effects on mood, stress, sleep, and body composition.

Study Design:
Randomized Controlled Trial (RCT) – Gold standard for evaluating interventions.

Participants:
42 adults (aged 40+ years) with Type 2 diabetes.
Stable diabetes treatment for 3 months prior to the study.
HbA1c levels between 6.1%–7.9% (moderate diabetes).
Participants recruited from Osaka University Hospital (August–September 2015).

Exclusion Criteria:
Severe diabetes complications or recent heart disease/stroke.
Unable to participate in light-to-moderate physical activity.

Intervention Protocol:
Groups:
Intervention Group (21 participants):
Received 12 weeks of Laughter Yoga + Standard diabetes therapy.
Control Group (21 participants):
Received Standard diabetes therapy only.

Frequency:
Weekly for the first 4 weeks.
Bi-weekly for the next 8 weeks.
Total Duration: 12 weeks (8 sessions).
Structure (90 minutes each):
Lecture (30 minutes): Laughter and health benefits.
Laughter Yoga (60 minutes):
Clapping, breathing exercises, role-play laughter, and relaxation activities.

Standard Therapy (Both Groups):
Oral medications.
Diet and exercise advice based on Japan's diabetes guidelines.

Measurements:
Primary Outcome:
HbA1c levels at baseline and 12 weeks.
Secondary Outcomes:
Body Weight and BMI: Physical changes.
Waist Circumference: Fat distribution.
Psychological Factors:
Positive and negative emotions using the Geriatric Depression Scale (GDS-15).
Stress and relaxation levels.
Sleep Duration: Self-reported hours of sleep.

Statistical Analysis:
Intention-to-Treat (ITT): Analyzed all participants regardless of dropouts.
Comparison Tests:
Paired t-tests for changes within groups.
Independent t-tests for differences between groups.
Confidence Level: 95%.

Results:
1. Blood Sugar Control (HbA1c):
Intervention Group: HbA1c dropped from 7.07% to 6.82% (P = 0.008).
Control Group: HbA1c slightly increased from 7.19% to 7.26% (P = 0.41).
Key Difference: 0.31% reduction in favor of the intervention group.
Psychological Improvements:
Positive Affect (Mood): Improved by 0.62 points (P = 0.049).
Negative Affect (Stress): No significant change.
Sleep Duration: Increased by 0.4 hours (P = 0.08), trending toward improvement.
Body Weight, BMI, and Waist Circumference:
No statistically significant changes.
Adherence Rate: 92.9% attendance for Laughter Yoga sessions, indicating high acceptance.

Conclusions:
Laughter Yoga is effective in lowering blood sugar (HbA1c) in people with Type 2 diabetes.It enhances mood, increases motivation, and improves psychological well-being.
It is a simple, fun, and feasible therapy to complement standard diabetes treatment.

Key Takeaway: Laughter Yoga offers scientifically supported benefits for managing diabetes by improving blood sugar control, mood, and stress levels. It is an enjoyable, cost-effective therapy that could complement traditional treatments and improve patient adherence to lifestyle changes

About LY and Diabetes 
Diabetes management traditionally focuses on medications and lifestyle changes like diet and exercise. However, many patients struggle to stick to these routines, and stress can worsen blood glucose levels.
Laughter Yoga is a non-pharmacological approach that offers physical and mental benefits by reducing stress, boosting mood, and improving metabolic function. It works by activating the autonomic nervous system, which regulates insulin sensitivity and glucose metabolism.
 

Physiological Effects: Laughter increases natural killer (NK) cell activity, improving immunity in diabetics. It helps regulate vascular tone and the renin-angiotensin system, reducing blood pressure and enhancing circulation. Studies showed laughter reduces post-meal glucose spikes by improving glucose utilization.

Endocrine Benefits: Laughter decreases stress hormones like cortisol and improves insulin sensitivity. It counters the "fight-or-flight" hormonal response, which often raises blood sugar.
 

Mental Health Improvements: Laughter reduces anxiety and tension, promoting positive mood and self-compassion. It enhances motivation to follow a healthy lifestyle and improves overall psychological well-being.