According to the researchers at the National Public Health Institute at Helsinki, Finland, seasonal weight change increases the risk of metabolic syndromes.
The result is based on an analysis of 8,028 individuals, over 30 years of age, who attended the nationwide survey.
The study says that people with metabolic syndrome have more seasonal changes in their mood and behaviour.
It concludes that the seasonal changes in weight in particular are associated with metabolic syndrome.
The risk of metabolic syndrome is heightened by 56 per cent in those having winter blues.
The negative effect of the seasonal changes equals to the protective effect against metabolic syndrome gained with regular physical exercise.
"Disruption of circadian rhythms has been implicated in the pathogenesis of metabolic disorders. Our results give support to the hypothesized links between the metabolic and circadian cycles generated and guided by the circadian clock," said Timo Partonen, MD, academy research fellow of the group.
"Our findings herein now extend these links to include relationships between the metabolic and seasonal fluctuations," Partonen added.
The results of the study suggest that abnormalities in the circadian clockwork predispose to seasonal changes in weight and to metabolic syndrome. This means that the circadian clockwork may well be a key to public health.
High caloric intake or low physical exercise for example may lead not only to obesity but also to hypertension, insulin resistance and abnormal circulating lipid levels. These abnormalities tend to coincide and contribute to metabolic syndrome.
The study is published in the January 23 issue of the online, open-access journal PLoS ONE.