We live in strange times. While a section of human society faces deaths and illnesses due to malnutrition, World Health Organisation figures state that worldwide obesity has nearly tripled since 1975. In 2016, more than 1.9 billion adults, 18 years and older, were overweight. Of these over 650 million were obese. 39 per cent of adults aged 18 years and over were overweight in 2016, and 13 per cent were obese.
According to the ICMR-INDIAB study 2015, the prevalence rate of obesity and central obesity varies from 11.8 per cent to 31.3 per cent and 16.9 per cent to 36.3 per cent respectively. In India, abdominal obesity is one of the major risk factors for cardiovascular disease (CVDs). Clearly, obesity is one of the main medical and financial burdens for the government.
In the Harvard Health Newsletter, Executive Editor Heidi Godman calls upon all self-confessed night owls to rethink their bedtime if they are genuinely concerned about belly fat and the health risks it carries. She cites the large international study of middle-aged and older adults that suggests that going to sleep late is associated with obesity and big bellies.
- The study, published online June 1, 2021, by JAMA Network Open, included almost 137,000 people of varying income levels from 26 countries.
- Participants answered questions about their sleep behaviours, with about 14 per cent saying they went to sleep at midnight or later.
- Compared with a bedtime between 8 pm and 10 pm, a later bedtime was associated with a 20 per cent greater risk of being obese (a body mass index of 30 or higher) or having a large waistline (35 or more inches for women, 40 or more for men).
- -The risk was even higher (35 per cent to 38 per cent) among people who went to bed between 2 am and 6 am. Long daytime naps were also tied to an increased risk for belly fat, especially among women.
- Going to bed earlier (before 8 pm) was not associated with obesity.
The Harvard report says that though the study was observational and doesn’t prove that going to sleep late will cause weight gain, it’s reasonable that it could possibly be the cause of obesity and visceral fat accumulation. The researchers speculated that delaying bedtime can throw off your circadian rhythm (sleep-wake cycle), which increases levels of the stress hormone cortisol and may play a part in abdominal obesity. Your body sets your “biological clock” according to the pattern of daylight where you live. This helps you naturally get sleepy at night and stay alert during the day.