Imagine a small lifestyle tweak that could simultaneously reduce your weight and risk of depression and boost your productivity. Not only is this free, but something almost anyone can have a go at. An old-fashioned behaviour our grandparents would have prescribed, it’s as simple as rising early on a regular basis. “Early to bed and early to rise makes a man healthy, wealthy and wise” — so the well-known saying goes. More intriguingly, science is supporting the age-old adage.
So why does life favour the lark? Want to know more about what becoming an early riser could do for you? Read on.
The rhythm of life
In recent years there’s been a surge in research-based recognition of old-fashioned health advice, like sleep, exercise and eating more plant foods. As part of this powerful health triad of sleep, exercise and diet a good seven- or eight-hour dose of nightly slumber is routinely promoted by most sleep experts.
More recently, though, it’s been discovered that when we do stuff, including going to bed and getting up, is also pivotal to our health. The underlying theory behind this is based on an emerging science known as chronobiology.
Chronobiology
Chronobiology is the scientific study of circadian rhythms (the cyclical 24-hour biological activities) and the impact of solar and lunar patterns upon them, as well as the application of this knowledge to human health and other species in nature.
Central to chronobiology is the understanding that from the lengthy perspective of evolution our bodies remain powerfully shaped by light and its absence — darkness. Being awake and active during the day and tucked safely into a cave at night favoured our ancestors, helping them maximise opportunities such as food in their surroundings as well as avoid dangers like predators. This adaptation of our biology to light and darkness remains rooted in our genes today.
A key player in our sleep–wake cycle is the central timekeeper or master clock of the body, the suprachiasmatic nucleus (SCN). This tiny but powerful region of brain cells sits in the middle of our brain, just behind our eyes and above the meeting point of the optic nerve, where it intercepts light signals entering our eyes. This enables it to track time in the external world. The goal of the SCN is to achieve synchronicity between the body’s functions and regular environmental patterns in the 24-hour daily cycle.
An overarching premise of chronobiology is that it’s healthier and more productive to synchronise sleep timing with the earth’s cycles of light and darkness as opposed to modern phenomena like TV programs, artificial light, evening work or something else. According to research, waking with the sun’s natural light and going to bed earlier — the other part of the sleep equation
— can translate into the following benefits.
A brighter, perkier mood
A number of studies reveal that night owls — people who feel more energetic in the afternoon and night and prefer to go to bed and rise later — are more likely to suffer from mood issues than larks — those who rise early and feel more energy in the morning and day. This is irrespective of how much they sleep.
Among these is a large-scale multi-sample study in 2021 of almost 840,000 people by the University of Colorado and the Broad Institute of MIT. Researchers first identified an average sleep midpoint of 3am, translating roughly to sleep hours of 11pm to 7am. By comparing health, genetic and sleep data, they found a one-hour shift earlier in the sleep midpoint was associated with a 23 per cent reduced chance of having major depression.
But can getting up earlier improve our mood? According to a few recent investigations, it can. In a 2019 experiment by Monash University, for example, night owls reported feeling less depression, stress and daytime sleepiness after their body clocks were brought forward by two hours across a three-week period. Scientists are yet to establish the exact factor behind the effect, but a leading theory is that sun exposure and its impact on hormones is responsible. Another popular hypothesis is that being a night owl conflicts with school and work timetables, leading to insufficient sleep and its consequences.
A trimmer body
Want to lose weight? Set the alarm earlier as part of your weight loss strategy. Mounting research shows staying up late at night is associated with eating unhealthier foods and a higher BMI (body mass index). One study of 2000 randomly chosen people, for example, found night owls more likely to indulge in high sugar and saturated fat foods and eat more on weekends than their early bird counterparts. The researchers from the Obesity Society blame this on the influence our biological clocks exert over metabolism and food choices.
Contrary to what many people think, there’s not just one body clock, but myriads of mini-clocks for all our biological functions, each running to its own persistent, innate rhythm but connected to the central roughly 24-hour master body clock that tracks time via light. Along with sleep, there are biological clocks for our metabolism, digestive function, hormones, bacteria and more. Related to this, there are optimal times for eating, focused mental tasks, physical activity and so on.
The nocturnal brain, for example, finds it more difficult to control impulses and make long-term decisions, according to a 2022 review article on the topic, “The mind after midnight: nocturnal wakefulness, behavioural dysregulation and psychopathology”. Thus, the outcome of eating late at night is greater likelihood you’ll make poor food choices.
Our digestive system also isn’t a 24-hour factory running at the same capacity all the time. Scientists have discovered that hormones associated with eating, such as insulin, which regulates blood sugar, and other digestive functions take a wind down after hours. Thus, eating late at night is a perfect storm for weight gain, as revealed by a 2022 study by Harvard Medical