Objective: To evaluate the effects of the laughing training on serum cortisol and nitrite levels in Thai private office workers.
Material and Method: Forty volunteers age 25 to 60 years from private offices were recruited. Thirty eight remaining
volunteers were divided into two groups: 20 for the experimental group and 18 for the control group. They were randomly assigned to participate in the training by matching up pairs of subjects with the same level of mean total scores from the
Suanprung Stress Test-60 (SPT-60). The program ran and continued from June to July, 2013. The control subjects took a rest in the same room as the experimental group throughout the experiment. The experimental subjects participated in laughing
training program for 3 days a week, 1 hour a day for 8 consecutive weeks. At 8.00 AM, eight milliliters of venous blood was drawn from individuals in both control and experimental groups at the beginning and at the end of the training program.
Serum cortisol and nitrite were assayed by electro chemiluminescense immunoassay and enhance chemiluminescense using high sensitivity nitrite, respectively.
Results: No significant difference was found in the mean of pre-post level of serum cortisol within control and experimental
groups. Additionally, pre-level of serum nitrite in the experimental group revealed significant difference from post-level of serum nitrite in control and experimental groups at p<0.05.
Conclusion: Laughing training is supposed to promote good health by reducing acute or chronic stress during work. In this
present study, laughing training for 8 weeks had significant effect on serum nitric oxide level indirectly determined by serum
nitrite level. However, this laughing training program had no significant effect on the serum cortisol concentration.

Keywords: Laughing training, Cortisol, Nitrite