An article in the journal Chronobiology International suggests that many of us are living as though permanently in the wrong time zone, because our body clocks are out of step with the routines of daily life. Though the body’s natural internal rhythm — what researchers call our chronotype — is largely genetically determined, it’s also reset by daylight. Office workers, who spend long hours staring at computer screens in artificial light, have body clocks that tend to run free, uncorrected by reality. That could help to explain why so many of us have trouble getting up in the morning. A study of more than 500 volunteers by Prof Till Roenneberg of Ludwig Maximilians University in Munich has suggested what may be an even more serious consequence of this social jet lag, that the more out of step your natural cycle is with reality, the more likely you are to become a smoker.
Prof Roenneberg said the problem was revealed at the weekends, when people reverted to more natural sleep patterns. Those worst affected by “social jet-lag” slept for about half their time off, simply to recover, he said.
The Scotsman, 30 Mar. 2006
Only around 10 per cent of people living within an hour of their natural body clock were smokers, but this rose linearly to around 70 per cent of people with 7 hours’ social jet lag or more, as measured by the difference between the mid-point of their sleep time on work days and free days.
New Scientist, 1 Apr. 2006