Circadian Rhythms
and Night Shifts

Gabe Circadian Rhythm, Day Plans, Health Risks, Healthy Lifestyle, Routines, Time Hacks, Time Management, Tips and Tricks

As a doctor in training, night shifts are a consistent part of life. This gets especially difficult for someone who is into optimizing their health. The World Health Organization classifies night shift work as a ‘carcinogen’. Circadian rhythms dictate specific times at which we are physiologically optimized for performance in different domains. It’s hard to stay alert and productive at night as the internal clock naturally causes your alertness to dip, so the pull to sleep can be powerful.

Night shift workers are more prone to developing certain illnesses, including cancer, cardiovascular disease, diabetes, obesity, and gastrointestinal disorders. Despite this, we need to try and minimize health risks. Interestingly, mental health problems can also arise due to night shift work. Having successive night shifts can be quite troublesome and cause circadian disruption. Certain genes can be up regulated or down regulated due to this subsequently causing ill health effects.



Unruly Nights

My shift would start at 8 pm and not end till 10 am, making it a 14-hour shift.  I would essentially need to reverse my day routine completely. I would have four shifts in a row and then would have to reverse my pattern again with a two-day break to do so for an 8 am start. This was a rather difficult task. Sleep dictates the rise and fall of melatonin, and these frequent shifts can really ruin your wake-sleep cycle, causing random bouts of sleepiness and alertness.

Working as a doctor demands much alertness and comes with a lot of stress, whilst error has to be minimized. With your circadian rhythm being disrupted, this becomes an even harder task to perform. On my night shifts, I felt tired and I often felt drowsy. When I returned home, it would be hard to sleep since I knew I had to be up to work for another shift the following night. I had to work four days consecutively forgoing sleep with no time to socialize, relax, exercise and had minimal time to eat out of shift. This can take quite a toll on your wellbeing.

Chaos Resolved

In order to minimize the health risks that come with shift work and improve my performance, I used a few techniques. Integral to maintaining my health was advanced planning. If I had a shift coming up on Monday, I would use the weekend to slowly shift my body clock later by a few hours. This allowed me to wake up as close to my shift as possible and therefore maximize my sleep, and gradually shift my circadian rhythm. I had to ensure I wasn’t sleep deprived and got 8 hours every night the week before. This would mean I was more alert when on shift.

To further mitigate the health risks with the inability to exercise for four days I would make sure I workout with increased intensity over the weekend and previous week so I can use these days as ‘recovery’. I did a combination of heavy strength training exercises to maintain muscle mass and high-intensity interval training for cardiovascular health. I would also ensure I hit the gym straight after my final shift so I can stay awake and sleep at a decent time to normalize my circadian rhythm for my normal day shifts the following week, I would also ensure I received morning light which helps suppress melatonin and would help keep me awake to readjust.


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Resistance/ Strength training? Should everyone be doing it? – Inactive adults experience a 3% to 8% loss of muscle mass per decade, accompanied by resting metabolic rate reduction and fat accumulation. Ten weeks of resistance training may increase lean weight by 1.4 kg, increase resting metabolic rate by 7%, and reduce fat weight by 1.8 kg. (Muscle burns more calories at rest than fat) – Benefits of resistance training include improved physical performance, movement control, walking speed, functional independence, cognitive abilities, and self-esteem. – Resistance training may assist prevention and management of type 2 diabetes by decreasing visceral fat, reducing HbA1c, increasing the density of glucose transporter type 4, and improving insulin sensitivity. – Resistance training may enhance cardiovascular health, by reducing resting blood pressure, decreasing low-density lipoprotein cholesterol and triglycerides, and increasing high-density lipoprotein cholesterol. – Resistance training may promote bone development, with studies showing 1% to 3% increase in bone mineral density. Resistance training may be effective for reducing low back pain and easing discomfort associated with arthritis and fibromyalgia and has been shown to reverse specific aging factors in skeletal muscle. – Try doing two strength training sessions a week working all the major muscle groups. Taken from – Current Sports Medicine Reports: July/August 2012 – Volume 11 – Issue 4 – p 209–216 doi: 10.1249/JSR.0b013e31825dabb8 @lifestyle_medicine_movement

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To aid this I also used ‘blue light blocking glasses’. It was imperative I slept straight after my shift. I would put on my blue light blocking glasses as it approached daylight so I could go home and sleep and not lose any time to get my ‘7 hours’. Blue light blocking glasses filters blue light and therefore prevent melatonin suppression. I also tried 2 mg melatonin sublingual to help induce sleep.

I would use various trackers to monitor my heart rate and activity level. I would ensure I remained active and would get 12,000 steps on my shift on average.

To prevent sleepiness and improve mental alertness, I would use a drink with 200-400 mg of caffeine near the start of my shift to help me stay awake. As caffeine takes on average 10 hours to leave the body, the effects would aid me during my shift, but would wear off when I needed to sleep at 10 am.

Carbohydrate timing can induce sleepiness and therefore I minimized refined carbohydrates the days I was working night shifts. As the body’s metabolism is less efficient in the night time (limiting any food intake after 2 am), I would consume fewer calories as opposed to when I was doing day shifts. I minimized fat intake and tried to have 1.5 g of protein per kg body weight. I would eat when waking at 5-6pm and then as it approached midnight ensuring my food was made up of mostly vegetables, berries and a source of lean protein.

Circadian Rhythm Optimization

Most importantly, it is important to avoid lapses as your body’s leptin and ghrelin signals are disrupted and feelings of hunger can cause you to reach for sweet calorie dense foods. The circadian misalignment can cause you to feel lethargic and low on energy and therefore, it is important to remain active. It was integral to take care of my mental health and have a positive frame of mind to limit my stress. I ensured I would socialize the weekend before and plan something to look forward to with friends on finishing my set of shifts. It also helped to take it as a test of self and be grateful for the ability to help many people when on shift.

I did notice my heart rate variability was much lower during night shifts (a sign of stress and less recovery) and it would take a week or so to start feeling normal again. But I believe if you plan smartly and stick to your plans by using a calendar, or an app like Owaves, it can really help you sustain that balance, hit your goals and stay happy whilst minimizing your health risks and finally realigning your circadian rhythm when the shifts are over. In the future, with chronobiology advancing, and the increased use of sensors, we will hopefully be able to get real-time feedback on our lifestyle changes and learn how to optimize for different scenarios.


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Glad to be joining the team! #Repost @lifestyle_medicine_movement (@get_repost) ・・・ WELCOME! We are so excited to introduce to you the Lifestyle Medicine Movement, led by a group of like-minded people who believe that a big part of your health should include your nutrition, your mindset, and exercise. Prevention is definitely better than cure! We'll be using this platform to aim to inspire you and share what we're passionate about, and hopefully you'll learn a few things along the way too! By way of introduction, here we all are: Peter: GP @drpeterjfoley John: GP @healthandfitnessdoctor Alan: Lawyer @thenutritional_advocate Kate: GP @the_sports_doctor Laura: GP trainee @doctor_eat_sleep_run_rpt Lauren: Doctor/entrepreneur @drlaurenevans CL: Surgical SpR Aileen: GP trainee @thisdoctorlifts Parsa: Emergency Medicine Clinical Fellow @drfoodiemum Chris: SEM Registrar/PT @thesportydoc Charlotte: Anaesthetics trainee @thegutsydoc Hud: Surgical registrar @fitbodydoc IK: GP trainee @drleroy Lis: GP trainee @therunningmedic Anjali: Consultant dermatologist @anjalimahto Nahdia: GP @dr.nahdia Zoe: GP/media medic @drzoewilliams Mike: GP @DrMikethe2nd Nick: GP trainee Clare Ashley: GP trainee @medic_mummy Susie: GP @doctorgetsfit Jennifer: Junior doctor @drjensjournal Andy: @drandib Sohaib: Junior Doctor and NHS Clinical Entrepreneur @drsohaibimtiaz We'll all be contributing to this page, and we'll be sure to sign each post as ourselves so you know who's who! Lauren x

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