Introduction

 The increase in inactivity among students and decrease in physical activity that occurs with aging caused sedentary lifestyle to be created from the standpoint of physical aspect both during school and after graduation (1). Therefore intervention for physical activity among students in higher education is of particular importance. Sports and leisure programs for the formation of active lifestyle while studying at university and after graduation can be very helpful (2-3). Physical education course is one of the best opportunities to develop students' knowledge and healthy life style. Half hours of general physical education classes are taught practically   and the other half is theoretical and it is expected   after learning this lesson, students create greater improvement in physical fitness and learning the sport skills, because in such classes, students understand the importance of participating in physical activity programs and are likely to continue physical activities outside of class time, or after the end of the course, throughout life (2).  The researches show that participating in the exercise and sports program plays a great role to obtain physical fitness and mental health.

Physical education is an effective tool to address the psychological needs
through which individuals can take advantage to satisfy their own needs and internal desires expression (4).

Meta-analytic studies have shown sport in the short and long term regardless of
  the type, intensity, duration and type of exercise program significantly reduces anxiety (5). Long-term studies on the effects of exercise on personality traits and mental health and have shown that exercise and physical education  are followed by psychological and social goals  not only as a recreational activity but also as a training –educational  tool (6). Researchers in the field of mental health believe that inactivity
is one of the factors affecting mental disorders
and that people with mental illnesses should be sought among people with low mobility (4; 6). Reduction of physical activity among students is higher than that in previous years. And on the other hand, conducted researches in recent years show that mental health problems are at different levels among students. Increase of students` attending counseling centers indicates an increase in mental health, social and academic problems among them (7). So, attention to students` mental health is very important because they are talented and selected segments of society and nation builders of tomorrow (8). Psychological disorders can create many problems in society
, greatly affect their academic performance and disrupt their social and emotional development. Mostly these disorders occur between the ages of 18 and 25 years old, when people come into adulthood. Many people at this stage of life begin their education at a university and so these disorders are associated with studying problems such as difficulty concentrating, inappropriate behavior, lack of social skills, defenseless, impulsiveness and severe anxiety experience. These problems are mostly complex obstacles on the way of study, lecturing and seminar of students (1). The importance of mental health issues has led many researchers to study in this field, including Jahani Hashemi et al, Rafie, Mousavi Poor; Aqa Najafi, More attention to the mental health of students is recommended (9-10). Also findings of Dadkhah, Mozafari and Mohammadi on 426 patients showed that 28% of medical students of Ardabil University are suspicious of mental disorder (11). Investigating whether sports activities (Public Physical Education) could have an effects on the increase of mental health due to its core mission of providing mental and physical health, regarding the fact that the frequency of mental health problems among the students is rising. So, in order to achieve this objective, we studied the effects of general physical education unit (I) on Bu-Ali Sina University students` mental health. To answer the question whether participating in physical education classes (1) has any effect on mental heal.

 Methodology

 The present study was a descriptive study of the quasi-experimental type (pre-test, post-test) .The statistical population of this study consisted of all male students entering Bu-Ali Sina University undergraduate before 2012 who had taken the general physical education course in the second semester  2013-2014 (N=238). 144 subjects were selected randomly based on the table karjcie and Morgan as the sample. After examining the samples in the pretest (first week of classes) , we chose the subjects whose  only  was  exercise of their general physical education classes during the week; After collecting the questionnaires, the study sample was reduced to 108. The instruments used in this research was  mental health questionnaire of 28 questions by (28-GHQ) Goldberg (1979), which has four seven-item  components including components of physical symptoms, anxiety and insomnia, social dysfunction and depression symptoms. Likert scale scoring of four values (0, 1, 2, and 3) was used. In this way, increases in test scores shows that mental health is lower and the score the individual can obtain from this questionnaire is from 0 to 84. In this questionnaire, based on different researches in the country, the cutting point is determined between 23-21 (1). In this case the cutoff point 23 was used. Score higher than 23 in total test indicates a mental disorder and below 23 was considered a sign of good mental health ( 1). Several studies on the validity of mental health (28-GHQ) have been performed. In one study, Goldberg and Williams reported the validity of the questionnaire 0.95. Various studies reported the reliability of this questionnaire between 84 to 91% (12). Some other studies reported the growth and the value of this questionnaire validity from 88 to 91% (10). In this study, the reliability using Cronbach's alpha was 0.89. In the present study to collect data, with prior coordination with the classroom teachers of Physical Education (I), pre-test questionnaire at the beginning of the first week of classes, and posttest questionnaires in the last week of classes were distributed and collected. Data were analyzed with descriptive statistics to summarize, categorize and describe data and inferential statistics (dependent t-test) to compare mental health scores in pretest and posttest. All statistical analyses were performed using SPSS₂₀. In this study, a significance level (α≤0.05) was considered.

 Findings

 The sample of this study was 108 students having taken general physical education in the second semester 1392-93. The mean age was 22.83+1.14 years. Pretest mean score of mental health was 21.86 ± 8.96 and post-test mean score was 22.55 ± 10.83. Also in the categorization of mental health scores in pretest and posttest, it was determined that 15.7% of the subjects obtained mental health pretest scores lower than 13 and 43.5% between 23-13 and 40.7% higher than 23.Also,in post test scores, it was shown that 16.7% got below 13,46.3% between 13-23 and 37% higher than 23 ,as shown in Table 1.