Some thoughts on night shift

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Working night shift introduces an entirely different set of stressors to our system. Our body’s circadian rhythms are designed around having light and food during the day time and dark and sleep (thus no food) during the night time.

One question you guys ask frequently is how make progress toward your health and/ or body composition goals while working jobs with irregular schedules.

Most of the evidence suggests that its very freaking difficult- that doesn’t mean its not possible- it does mean that its difficult.

Let’s do a thought experiment. All of a sudden there’s two of you- person A and person B.

Person A and person B eat the same number of calories every day and do the same amount of exercise every day. Person A and B also get the same number of hours of sleep every day.

The only difference is that Person A sleeps from 10pm-5am and person B has a sleep schedule that varies- sometimes its 8am-3pm and sometimes its 10pm-5am depending on their work hours. I think there is enough evidence supporting alterations in energy expenditure and circadian rhythms with varied sleep hours to argue that Person A is going to have a more regular circadian rhythm (which translates to more consistent hormone fluctuations) and probably more lean tissue and less fat mass than Person B.

So you’re saying that if I want to make progress toward my health/ body composition that I should work day shift? No. I think you can still make improvements if you have an irregular schedule- and I think that you could make more efficient progress if you were working normal day time hours. And as with anything, as you get closer to the extremes of the spectrum- progress will be more difficult.

This article discusses differences in respiratory quotient (which is marker of whether we are primarily metabolizing fat or carbohydrate) at different times of day and night. Maybe not surprisingly, fat metabolism is higher at night while carbohydrate metabolism is higher during the day. This finding alone would suggest that eating higher fat (and lower carb) meals during night time hours would work better with our metabolic function. As always this is a research finding which doesn’t mean it is a rule- it does mean that there is a physiological basis for trying a higher fat diet (or even fasting) during your night shift.

With my clients who work irregular schedules, we tend to focus on the following things:

  1. Keeping a 10-12 hour fasting window each day (I’ve also been experimenting with some longer fasting windows with women- who I don’t normally love fasting for- but in the context of shift work, it seems to have some useful applications)
  2. Prioritizing 7-8 hours of sleep (regardless of what time of the day it takes place)
  3. Prioritizing strength/ body building training (of course there are unicorns who can continue to thrive in HIIT environments like Crossfit- but this isn’t the majority with what I’ve seen). Check out LCK’s Paragon Programming if you’re not already doing it :))
  4. Prioritizing water intake (maintaining hydration status can help with excess water retention that can take place due to changes in cortisol rhythm that occur with irregular schedules)
  5. Using caffeine to help you switch from sleeping during the day back to sleeping at night

With some clients who struggle to keep calories up on the days where work hours are irregular, we set calorie goals lower on those days and then increase on off days to keep average where we want it over the course of the week. Other clients don’t have an issue here and keep calories consistent across days.

I’d love to hear from you guys! If you work nights (or have in the past), what do (or did) you struggle with the most? And any tips and trick you love that have helped?



For further reading:

Impact of Shift-Work and Night Shift-Work on Thyroid: A Systematic Review

Human Resting Energy Expenditure Varies with Circadian Phase

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