Sleep & Chronobiology

Did you know that time of day might actually have an effect on how the body responds to nutrition, exercise and even social interactions.

The science of chronobiology gives some incredible insights into why some bodies respond better than others to exercise, food, meditation and even socialising at particular times of the day.


The brief overview:

Sleep and ph360Knowing if you are a night owl or an early bird is critical for timing of training, nutrition and general health. If you think you are a night owl, listen to your body and train later in the day, rather than dragging yourself out of bed first thing in the morning. It might actually be causing you more stress.

More detail:

There are night owls and early birds, and everyone everywhere in between! These sleep preferences are controlled by lots of genes, but typically the appropriately named CLOCK genes are known for their ability to tell the time, and adjust your physiology accordingly.

These genes help control our response to the light and dark cycle, and they also sync up with other organs in our body. What’s really interesting is that while the light/dark cycle is very robust to change (it takes a lot to alter it), things like our digestion can be altered depending on our environment – i.e. more susceptible to epigenetic change. When you are doing shift work, your body adjusts to digest through the middle of the night, where normally it would be doing this through the day. Now while this is handy, this makes the central (light/dark) cycle clock, and digestive clock fall out of sync, and this can cause chronic stress over time. This can begin a process of disease…

This extends to exercise as well. When you work out in the morning and you are an early bird, it feels great and energising. When you are a night owl and you drag yourself out of bed for a morning bootcamp, it might actually be causing more stress, which can lead to a tendency to then store and conserve energy. This is all compounded by the fact that there is actually a high BMI in those who are night owls. However, this doesn’t mean night owls are more unhealthy, it just means they have a tendency of a particular somatotype (we explain a lot about correct somatotyping for genotype in our webinar series

Having worked with genetics through the ph360 assessment platform for 3 years, the comparison between utilising the best sleep timing and getting the right amount of sleep and not understanding these principles is, night and dark ;p

Whether it be having more energy later in the day, or avoiding chronic inflammation associated with arising at the wrong time, knowing your genes, and knowing how to make them happy will revolutionise your health. The best thing is that this particular interventions requires no effort at all, all you need a is a comfy bed and some quiet time.

Written by Dr Cam McDonald

(Accredited Practising Dietitian, Accredited Exercise Physiologist, ph360 Prescriptive Coach)


Atkinson G, Jones H, Ainslie PN. Circadian variation in the circulatory responses to exercise: relevance to the morning peaks in strokes and cardiac events. Eur J Appl Physiol. 2010;108(1):15-29.

Aguilar-Arnal L, Sassone-Corsi P. The circadian epigenome: how metabolism talks to chromatin remodeling. Curr Opin Cell Biol. 2013.

Qureshi I, Mehler M. Epigenetics of Sleep and Chronobiology. Current Neurology and Neuroscience Reports. 2014;14(3):1-11.

Salavaty A. Carcinogenic effects of circadian disruption: an epigenetic viewpoint.(Review)(Report). Chinese Journal of Cancer. 2015;34:38.



Author: Dr Cam McDonald

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