Scientists have linked “owls” with more frequent receipt of disability pensions

People with an evening chronotype, or “owls”, by the age of 58 were 70% more likely to receive disability pensions than “larks”, follows from a study by scientists at the University of Oulu in Finland, writes the Financial Times.

The researchers examined data from more than 5,000 people: 12.1% of women and 8.3% of men with an evening chronotype received payments versus 7.2 and 5% among larks. The difference persisted after accounting for education and occupation.

Lead author of the study Tapio Ryaiha noted that if the work schedule does not correspond to the natural rhythm of the body, the results are worse. The study is published in the journal Occupational & Environmental Medicine.

The work does not prove that evening chronotype alone leads to more frequent disability pensions. Oxford University researcher Clara Albignana pointed to the possible role of a mismatch between biological preferences and work schedules.

University of Cambridge researcher Nina Rzehojek has suggested that more flexible working hours could reduce this discrepancy, and Keele University cognitive psychology lecturer Darren Rhodes noted that aligning the schedule with the chronotype could improve sleep and reduce "social jetlag.".

Circadian rhythms regulate sleep, hormone production, appetite, digestion and body temperature. Their disorders are associated with an increased risk of obesity, type II diabetes, cardiovascular disease and depression. The body’s internal clock can be affected, in particular, by night work and sleep disturbances.

British sleep specialist Nick Littleheils noted that it is important to take into account the chronotype - the individual propensity of the body to a certain time of sleep and wakefulness. Circadian rhythms, he said, affect hormonal levels, body temperature and the daily sleep cycle.