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  • Writer's pictureSophie Bostock, PhD

Can night owls become early birds? A question from the Power Hour podcast...

Updated: Jan 7, 2020

Introducing the Power Hour

Have you ever met anyone who simply exudes good health? Meeting Adrienne Herbert is a bit like meeting sunshine. Warm, energetic and (even with no make up), completely stunning, she is also incredibly likeable. Perhaps this is why her podcast, Power Hour, has had hundreds of thousands of downloads and rave reviews.

I was lucky to meet Adrienne on a panel at Women's Health, and she kindly invited me into the studio this week. If you could do with a motivational burst, I recommend subscribing to the podcast. Adrienne gets up at 5:30am every morning and advocates adopting an early morning routine, or 'Power Hour', to kick start your day. So could the Power Hour work for you?

What's your Chronotype? Early birds and night owls

If the thought of rising before 6am fills you with dread, and you doubt that you could ever bounce willingly out of bed before 8am, your biological clock may be operating in a different timezone to Adrienne's.

We all have an inbuilt circadian rhythm, or body clock, which keeps all the processes in our body operating on a 24 hour cycle of activity and recovery. In fact, every single cell has its own internal molecular timekeeper, ticking away with a 24-hour beat. A master clock in the brain, the SCN, uses sunlight and darkness as signals to help keep all the individual clocks co-ordinated, and working together in synchrony.

Some of us have internal clocks that run slightly faster than others. Without light cues to rely on, the average for humans is about 24.2 hours. Chronotype is the term given to describe our natural preferences for times of waking, activity and sleep. 'Early birds', who can wake up at dawn without an alarm clock, are thought to have a shorter or advanced cycle, so they get sleepy earlier in the day. In comparison, 'night owls' have a delayed clock, so they struggle to feel alert before mid morning, but often feel more energised in the late afternoon or evening.

There is no single definition of chronotype, and most studies suggest there is a bell shaped distribution, with fewer people at the extremes, and most people in the middle.

Is my chronotype fixed?

The speed of our clocks is thought to be programmed by our genetic code, but it is designed to adapt to cues in our environment, and also changes as we age. Children and the elderly tend to be early birds, whereas teenagers have a delayed clock, which makes it genuinely difficult to wake up early in the morning or go to bed early (it's not just an excuse!).

A recent US study suggested that men have later chronotypes than women before the age of 40, but earlier chronotypes in later life.

From an evolutionary perspective, being able to adapt our rhythms in response to light makes sense, since we needed to be able to change our levels of activity to respond to the changing seasons throughout the year - even before we discovered the aeroplane.. and jetlag.

Light isn't the only 'Zeitgeber', or time giver, but it is probably the most important cue for keeping our clocks in sync with the environment. Food, exercise and social interaction can also send alerting signals to our internal clocks. When external and internal signals persistently contradict each other, for example when we work night shifts, biological processes like the metabolism of food and immune system regulation get less efficient, which is thought to contribute to the risk of diseases like diabetes, and cancer.

So.. how do I shift my chronotype?

Currently our best guess is that 50% or less of our chronotype is down to genetics, so we definitely have scope to change it. While you might be predisposed to waking up at the same time as your parents, recent research suggests that you can adapt positively to a new routine by actively managing your time-giving Zeitgebers - especially light and food.

For example, a study published this month explored what happened when 22 night owls, who typically woke up at 10:15am and went to sleep at 2:30am, adopted the behavioural patterns of earlier birds, for 3 weeks. They were asked to:

  • set their alarm 2-3 hours before their typical wake up time

  • get plenty of outdoor light in the mornings

  • go to bed 2-3 hours early

  • limit light exposure in the evening

  • stick to the same sleep/wake times on both work days and weekends

  • have breakfast as soon as possible after waking up

  • eat lunch at the same time each day

  • avoid eating dinner after 7pm.

After 3 weeks, participants had faster reaction times and grip strength in the morning, a shift in the timing of their peak performance from the evening to the afternoon, and - perhaps most importantly - an improvement in their wellbeing, with lower overall levels of stress and depression.

Admittedly, this is just one small study, but it builds on growing evidence that adopting a routine pattern of behaviour which is consistent with waking as it gets light, and winding down as it gets dark, helps to keep our circadian rhythms aligned and our bodies and minds fighting fit.


If you'd like to know more about circadian biology, I'll keep adding more on this topic. I've just read Dr Satchin Panda's book, The Circadian Code, which I'd definitely recommend.

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