Our study showed that some subscales of sleep quality are associated with FBS, TG, BMI and physical activity level. Subjective sleep quality and sleep latency were associated with both investigated biochemical factors (FBS, TG) and physical activity, although in the opposite direction. Indeed, increase in the score of those subscales is associated with increase in serum level of FBS and TG, while increase in physical activity level is associated with decrease in the score of sleep quality. The higher score of subscales of sleep quality, shows the weaker sleep quality. Although a recent meta-analysis found that exercise training resulted in improvements in sleep quality in adults with sleep problems(24), other trials have found minimal to no improvements in sleep quality due to exercise training(25). These controversial findings can be explained by different severity of sleep disorders and level of exercises in different studies. The association between poor sleep quality and increase in FBS and TG level in our study, is consistent with Khorasani et al’s study. They found that serum levels of TG in people with poor sleep quality is higher than those with good sleep quality (26). In the current study, nothing was found between sleep quality, total cholesterol, HDL-c, LDL-c, and Insulin. This results was agreed with Zhu et al. study, that found no significant associations between PSQI score and these biochemical factors (27). Poor sleep quality may have effects on FBS and TG through some mechanisms. For example, chronic or acute sleep deprivation can increase appetite through increase in an orexigenic hormone, Ghrelin, and decrease in Leptin as an anorexigenic factor (19, 20). These factors may lead to weight gain that in turn, can cause increase in FBS and TG level (9, 21). Furthermore, poor sleep quality decreases glucose uptake in skeletal muscle via the hypothalamic–sympathetic nervous system axis and β-adrenergic mechanisms due to decrease in Leptin level (28). Increasing in turnover of triglycerides, inhibiting the basal and insulin-stimulated de novo lipogenesis and stimulating the oxidation of glucose and free fatty acids are of the other probable mechanisms (29). On the other hand, obesity could increase the risk of obstructive sleep apnea, which in turn, may increase metabolic impairment, including dyslipidemia(30, 31) Poor sleep quality was associated with higher BMI in the current study. Studies have reported that trends in sleep disturbances parallel trends in obesity. Despite the parallels and the related mechanisms, the association between sleep disorders and obesity is not fully understood (32, 33). Some authors showed that people suffering from sleep disorders are more prone to gain weight (34). Recent findings suggest that diet quality is an important mechanism that links obesity to sleep disorders(35). It is possible that some nutrients act on inflammatory hormonal responses involved in hunger-satiety mechanism and energy metabolism. We did not find any significant association between dietary intakes and sleep quality. Our finding is inconsistent with some limited evidences showing that poor sleep quality is related to higher calorie intakes and lower intakes of fish (36, 37) low energy‐density fruits (38) and vegetables (39-41). These controversial findings may be for the reason of health status of our participants. Our participants did not have any communicable diseases like diabetes, while most of the other studies have been conducted on people with diabetes or dyslipidemia. The other probable reason may be severity of sleep disorder in our participants. The mean total score of sleep quality in our study was 6.8, while the range of score is from 0 to 21. It is possible that sleep quality in our participants is not such weak to be effective on dietary intake. Investigating sleep quality instead of quantity may be the other probable reason for these controversial findings. Since there was not any association between sleep quality and dietary intake, it seems that the correlation between poor sleep quality and higher BMI, is more contributable to lower physical activity than higher energy intake. Furthermore, because of the design of current study, it is not possible to determine if weight gain lead to sleep disorders or sleep disorders lead to obesity. It is suggested conducting a prospective study to assess the causality.