Training & Shift Work

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This article explores shift work, its impact upon life and training, and my own three-week experience as a case-study for how I have tried to manage things.


Around 1 in 5 of us, across all sectors, are involved in shift-work.

Healthcare systems around the globe are fuelled on the sleep deprivation and toyed circadian rhythms of its workforce. With our increasing understanding of the dire implications for sub-optimal sleep across the lifespan, what is a shift-worker to do?

Aside: learn more about the why poor sleep will wreck you:
Matthew Walker on Joe Rogan
– Or just buy the book, Why We Sleep (highly recommend)

I’m working in Emergency Medicine right now, and whilst it is absolutely hands-down the most enjoyable job I have done so far, it is also unique in its work schedule. Shifts are a smorgasbord of 8am-8pm, 12pm-12am, 8am-4pm, 8pm-8am, 4pm-12am, etc, and rotas are a sea of different colours (I’ve come to understand that emergency care people love colours (red zone, green zone, red scrubs, green scrubs etc)).

The areas of life that rapidly shifting work patterns can affect are indeed many (?all).

But I want to address one main area: physical training.

I intuit that if you can continue to progress in training (eg. ‘mo’ weight on the bar’) then this progression serves as a reasonable proxy for how well you’re holding it together in other areas. In turn, you generally need to reasonably manage other areas of life to continue to progress your training.

• You need to be well slept
• Nutrition must be reasonable
• Fatigue is hopefully well managed

Additionally, as I have hopefully convinced you elsewhere, resistance and cardiovascular training can provide the additional physiological resources and buffer space to deal with the health insults that come from working funky hours.

“It has been postulated that those shift workers who adopt active/engaging coping mechanisms, including habitual involvement in physical activity, are better able to tolerate the stresses and strains of shift work and are generally healthier.” [1]

Atkinson et al

And besides, I just don’t want to spend the next four months of this rotation in a state of atrophy and deteriorating gainz.


A bit about shift work

There have been efforts to investigate the “‘triple whammy’ of sleep deprivation, disturbed circadian rhythms and disrupted personal life associated with shift work” [1].

Mammals (including you and I) tend to operate on a 25 hour circadian cycle. These cycles, which involve fluctuations in body temperature, respiratory rate, urinary excretion, cell division, and hormone production, can be influenced by external factors such as social context, dark-light cycles, stressors and working patterns [2].

“There is a marked increase in preventable medical errors, including those resulting in fatalities, when medical residents work frequent extended-duration night shifts.” [3]

Rajaratnam et al

Thankfully, we are out of the bad old days of 100+ hours per week (my consultant from the US told me how he endured these for years). But performance can still be affected by badly managed work patterns.

On an individual level, there is good evidence that cardiovascular risk is significantly elevated in shift workers, by up to 40% compared to non-shift workers. Reduced insulin sensitivity, altered blood lipid management, reversed daily cortisol rhythm and increased mean arterial pressure are some of the mechanisms that have been implicated [4]. Angina, metabolic syndrome, hypertension and myocardial infarction are some of the grim outcomes of these altered functions.

Even a potential increase in cancer risk has been described for those working shift patterns [5].

Additionally, doctors, police, and other shift workers have been demonstrated to experience impaired cognition, and increased levels of anxiety and depressive symptoms when working prolonged shifts [6].

There is also the harder-to-measure impact on shift workers’ social and family lives, and the challenge of trying to “adjust their circadian rhythms or lifestyles sufficiently to be able to synchronise with such an altered existence’ [1].



Three weeks of shifts: an example of my rota

The below is an example of one of the more heinous run of shifts (quite a few 12 hours). I will be using this three week stretch as a case-study for how I can (hopefully) manage my work, life, and train meaningfully.

MonTueWedThurFriSatSun
8-48-4Off4-1212-1212-1212-12
4-12Off12-1212-1212-12OffOff
12hr Night12hr Night12hr Night12hr NightOffOffOff

24 Hr breakdown for a 12 hour shift:

– 7 hours sleep (in an ideal world)
– 45 mins get ready
– 30 minute drive and change into scrubs etc
– 12 hour shift
– 45 min change out of scrubs and get home
– 30-45 mins deload and eat something

Total: 21 hours 30 mins
Spare time: around 3-ish hours

Issues to deal with:

  • Sleep
    The biggie. For me, shift work usually results in less and lower quality sleep. My last night shift had me trying to sleep listening to a white-noise background track of the death star through earbuds, because my immediate neighbour began hammering stuff right next door. Which is a pretty reasonable activity for 2pm on a Sunday, but didn’t make me want to hammer them any less.
    12 hour shifts that end either midnight or 8am mean you are getting home and getting up at times that are less than optimal, from a performance perspective. Predictable hormonal cycles become scrambled, and so cortisol may be just peaking when you should really be going to sleep. This impacts sleep quality, energy, and all aspects of training.
  • Psychological bandwith:
    I tend to easily ‘take work home’ with me. As a baseline, I’m quite a neurotic individual, and so I’ll tend to mull over patients I have seen, question whether I handed everything over and accurately to colleagues on the incoming shift, analyse decisions I made through the shift etc: work-related angst can bleed into off-time for an hour or so. Not switching immediately off after work does tangibly sap energy and affect mood, which both impact on training.
  • Energy intake:
    Shift workers generally fall into one of two camps here: over- or under-eaters (I’m in the latter). A&E shifts tend to fly by for me, and occasionally I forget to take all my breaks. Jobs and tasks pile up and suddenly taking a break at 6am when you need to handover and go home at 8am doesn’t seem like a great idea. As a result, over a 12 hour shift, I’ll often eat only once. If I’m on nights, my desire for sleep overrides my appetite, and so I may only get 2 proper meals in a 24 hour cycle. Coupled with being on feet and very hands-on all shift, this can push me into quite a good-going calorie deficit – not what I want.
  • Family, friends, other stuff:
    I’ve just lumped all this into its own category for the simple point that (likely) none of us are completely solitary monks. It can be trying for spouses who, for the best part of a week, only see their other half stumble in at 9am, grunt, and collapse into bed with a trail of clothes left behind. So some concerted effort has to be made to at least pretend you have relationships with other humans.
  • Blood sugars:
    As a type 1 diabetic, this can be a pain. I have different background insulin profiles that vary throughout the day due to shifting degrees of insulin sensitivity. This becomes completely skewed when routine is out the window. Luckily, being on my feet has levelled out my blood sugars and lowered my insulin requirements markedly, so this is less of an issue than I thought it would be.
  • Current injuries:
    I have some bilateral medial epicondylitis going on currently, as well as an occasionally ‘tweaky’ (not twerky, sadly) lower back. Trying to back squat early AM has never been possible with my back, and the elbows flare at weird times. Just two things to throw in the mix.
  • Equipment/facilities:
    With only a few spare hours each day on 12 hr shifts, I’m lucky enough to have the option of not schlepping to the gym and back again. Having a squat rack in the living room certainly has its advantages, despite the absolute train-wreck of feng shui.
When needs must.

Now that the moaning is out of the way, where does this leave me?

Situation/problem: Shift work and subsequent pressures on sleep/recovery/life.

Goal 1: maintain health, do not get injured.
Goal 2: make progress in training (strength/hypertrophy).
If shift work is an excuse to settle for maintenance, then nothing will ever improve.

Approach: pragmatism and conservatism
do what you can with what you have where you are.’

In my experience, working twelve hour shifts with varying time patterns mostly results in treading water when it comes to the rest of life. I don’t want to be making significant clinical decisions in a demanding emergency department feeling under-slept and sluggish, so any time outside of work is generally devoted to getting food in and sleeping as much as possible.

With this prioritisation in mind, the question is raised: ‘what is the least amount of training that I need to do, taking into account the issues outlined above, to ensure some progress’.

And besides, what else am I going to do? not train?

Minimum effective dose
A term borrowed from medicine, the minimum effective dose (MED) is the minimum exposure required to a certain therapy or stressor (in this case training) that will bring about a desired result. When starting someone on an anti-depressant or diuretic therapy, we start low, go slow. In the case of training, it is usually more preferable to train nearer the maximum recoverable dose, to ensure the greatest progress. But in the case of shift work, and indeed many times in life where training is not the biggest priority, we want to aim at the minimum effective dose.

This is a nice concept to use as a goal and to orient training variables, but it must be emphasised that this is not an exact science, and there is no way of actually working out somebody’s MED. We can try our best, but all the biopsychosocial aspects that feed into training are far too complex to account for. Training, often like medicine, can include a great degree of ‘try and see’, and we can never be 100% certain how an individual will respond to a therapy or training modality. We use theory and concepts as GPS points to guide us, but the actual roads to get somewhere are usually much more empirical and individual.


Below are some general principles that have helped me, and hopefully may be of use to you.


Sleep(!)
WHOA, I’m glad I read this groundbreaking article”, you’re thinking.

But sleep is literally the foundation upon which you’re entire life rests. The quality and duration of a preceding sleep will permeate into all activities, mood, cognition, physical preparedness, and performance. Insisting to train, work, and be a human on poor sleep will grind you down into dust over (a short) time.

Blacked out room with no sunlight, +/- eye covers. Earplugs. Cool ambient temperature in the room. Time caffeine to limit its exposure a few hours before sleep. No phone or screens in bed.

The data indicates we should aim for minimum 7 hours.
Not 6 and a half. No, you’re not special. Seven.

Manage fatigue flexibly
We generally know that optimal rest periods between training sessions (depending on muscle groups, intensity etc) sits at around 48-72 hours, with the thought that it roughly takes this long to recover from the previous session. But fatigue is not just the hole we dig ourselves from the previous training session, its a generic catch-all term for everything.

If you are sleep deprived, stressed, looking after kids, multi-tasking, etc these all pour into the delightful fatigue bowl; the more, the higher the risk of injury/poor performance/etc.

This is all to say that I reminded myself of this when thinking about organising my training, and that a run of 12 hr night shifts would dig me a bigger ‘fatigue hole’ than standard day shifts. So I adjusted variables of intensity/volume depending on what was going on, and didn’t plan workouts in isolation from everything else.

A good heuristic is ‘don’t be a d*ck’. If I can feel the elbow pain flaring, but I’ve still got X number of sets left on pullups, or I’m just smashed and not able to hit certain weight on squats, I need to have the wisdom to change what I’m doing or just delay the session until the next day.


Spread the volume
Volume is an excellent shovel for fatigue-hole digging.
Usually, a session would take me around 1.5 hours to do. I’ve decided to get the same amount of work done over the week, but to spread that volume across days.

Normally, a Monday session, for example, may be:
A. Squat
B. RDL
C1. Back extension
C2. Ab rollouts

Instead of this, I might do something more like:

Split the volume across two days:

Monday would be either:
1. Squat and RDL, as per normal.
or
2. Dan John style ‘One Lift a Day’ – which would be something like 8-10 sets of just back squat. Nil else.

Tuesday would be:
Superset back extension and ab rollouts for 5-10 sets.

The ‘One Lift a Day’ approach was particularly refreshing, especially if trying to get in a session on the morning before a 12 hr shift start. Reasons being:
– Less stress of feeling the need to get to the next exercise
– Had enough time to build up meaningful volume on, e.g. squat
– Time to really practice the movement
– Emphasis on a main lift

I found that I was much fresher, and actually could perform the exercises and finish the session feeling quite energetic rather than utterly taxed. If you only have 30 minutes to train in a day, make it count. Spread one session across 2-3 days and train with intent and focus during those 30 minutes, perhaps with just one exercise. You absolutely will make progress. Fatigue and DOMS is not a measure of progress, particularly when in this context.


Limit maximal effort work
By maximal effort I am referring to lifts generally around 90%+ of 1RM. Another (and to me, more preferable) way to gauge intensity in this context is by limiting sets to an RPE of 8.

RPE = rate of perceived exertion.
An internal measure of intensity.
e.g. 8 RPE = a set finished with 2 possible reps left.
Requires some degree of experience to accurately feel.

% 1RM = percentage of maximum weight one can lift, one time.
An objective measure of intensity.
e.g. If I can squat 100kg once, but no more, my 75% 1RM would be 75kg.
Can be too rigid depending on how one feels.

Lifting at 75% of my squat 1RM is just dandy, but being a few shifts deep into a run of nights may cause that 75% to feel and move more like a 95% lift. Fatigue and excitability are very hard to predict during swinging shift patterns, when your cortisol doesn’t know which was is up or down.

By this logic, using an RPE framework to set subjective intensity has the advantage of allowing a sliding scale for objective weight lifted, whilst maintaining a particular intensity. This allows the tides of stress/tiredness/under-eating etc to simply ebb the weight on the bar in a direction that will be appropriate and not bury me on the spot.

Why 8 RPE?

Well it’s an intensity that generally allows repeated sets with good recovery between. If done properly, this intensity is also plenty high to ensure progress is made without driving oneself into the dirt. Training performed at intensities as low as 6-7 RPE has been shown to deliver significant results in strength and hypertrophy [7].


Aim for minimum 2 sessions per week (roughly)
In an attempt to invoke the minimum effective dose principle, at least 2 sessions a week will keep the boat afloat. The reason for adding ‘roughly’, is because a Mon-Sun week structure becomes quite arbitrary if your rota has zero respect for the gregorian calendar.

Although it is likely that a higher frequency of sessions results in greater strength and hypertrophy results, there is also evidence to suggest that frequency does not make a significant difference for strength gains, and total weekly volume may be more important [8].

Whatever the case may be, my own experience, and going out on a limb tell me that minimum 2x per week will ensure progress continues, and may not be that inferior to higher training frequencies per week [9].


Using an A/B training split has helped with this, by which I mean just having two potential training sessions that can be slotted around the week. For me, this currently looks like:

A: Upper
A1. Bench
B1. Handstand pushup
B2. Pullup
C1. Overhead press
C2. Barbell row

B: Lower
A1. Squat variation
B1. Romanian deadlift
C1. Back extension
C2. Standing ab rollouts

By having just two sessions to alternate between, despite not being able to guarantee which day I will train, frequency is usually high enough per muscle group because I’m not faffing around with lots of variation. Also, using an alternating emphasis on volume/intensity every other session helps recovery and progress for me.

Even with the above rota example, I’m still managing to train 3-4 times per week. But I know that I could still keep things rolling forward if I had to drop that to 2x per week for a while.


Other general training tips on tight time:
– Use the main movement as the warm up, e.g. from body weight squat –> empty bar squat –> gradually adding weight. NO flossing/stretching/rolling/knitting (unless you need to work on a specific injury/restriction.
– If you want to stretch, use the rest periods between sets to do so. But only for body parts not being used in the exercise – e.g. stretch hamstrings with bench press is ok, not stretch shoulders with bench press.
– Compound movements > isolated movements
– Free weights > machines
– Repetition > variety
– Superset all accessory and auxiliary work
– Have a well-maintained playlist (pressing ‘skip’ on spotify adds up quickly)
– 90-120 seconds rest maximum per set.
– If you can’t justify the exercise in your routine, ditch it


Pragmatism
And finally, being pragmatic and not perfectionist has helped me.
Since going onto shift work, my training has undoubtedly suffered. Steady training progress that the predictable work schedule of Family Practice allowed has been replaced by an ad-hoc and highly varied training pattern.

But boo-hoo. That’s the price of entry to have the privilege to do the kind of work that I’m allowed to do in an emergency department, where people are coming to hospital in their most terrified, acute, uncertain states. To be the person receiving them must intuitively come with some sort of price, since it’s a very specific position to be allowed to occupy in society.

When it comes to physical pursuits:

Do what you can, with what you have, where you are.

Theodore Roosevelt

As one of my A&E colleagues told me when asked about her training habits:

Her: “I just go lift straight after work for about an hour and a half”
Me: “Even on 12 hour shifts?”
Her: “Yep”
Me: “Even on 12 hour nights?”
Her: “….yep”
Me: “……..”
Her: “usually 5-6 times a week….”
Me:..


Additional links/info:


References:

  1. Atkinson G, Fullick S, Grindey C, Maclaren D. Exercise, energy balance and the shift worker. Sports Medicine. 2008. 
  2. Harrington JM. Health effects of shift work and extended hours of work. Occupational and Environmental Medicine. 2001. 
  3. Rajaratnam SMW, Howard ME, Grunstein RR. Sleep loss and circadian disruption in shift work: Health burden and management. Med J Aust. 2013; 
  4. Morris CJ, Yang JN, Scheer FA. The impact of the circadian timing system on cardiovascular and metabolic function. Prog Brain Res 2012; 199: 337-358.
  5. Straif K, Baan R, Grosse Y, et al. Carcinogenicity of shift-work, painting, and fire-fighting. Lancet Oncol 2007; 8: 1065-1066.
  6. Smith-Coggins R, Rosekind MR, Buccino KR, et al. Rotating shiftwork schedules: can we enhance physician adaptation to night shifts? Acad Emerg Med 1997; 4: 951-961.
  7. Helms ER, Byrnes RK, Cooke DM, Haischer MH, Carzoli JP, Johnson TK, et al. RPE vs. Percentage 1RM loading in periodized programs matched for sets and repetitions. Front Physiol. 2018; 
  8. Ralston GW, Kilgore L, Wyatt FB, Buchan D, Baker JS. Weekly Training Frequency Effects on Strength Gain: A Meta-Analysis. Sport Med – Open. 2018; 
  9. Yue FL, Karsten B, Larumbe-Zabala E, Seijo M, Naclerio F. Comparison of 2 weekly-equalized volume resistance-training routines using different frequencies on body composition and performance in trained males. Appl Physiol Nutr Metab. 2018;