Working nights long term

Plenty of people work nights for decades and are fine. Plenty of people find it costs them more than they expected. Both are true, and the difference is partly luck and partly things you can influence.

What the evidence supports

Handled honestly, because this topic attracts both scaremongering and dismissal.

The associations are real. Long-term night and rotating shift work is associated with higher rates of cardiovascular disease, metabolic syndrome and type 2 diabetes, and the IARC classified shift work involving circadian disruption as a probable carcinogen. Sleep disorders are markedly more common.

They are dose-dependent. Risk rises with years worked and with the number of night shifts. Five years is not twenty.

They are confounded. Shift work travels with other things — worse diet, less exercise, higher smoking rates, lower income, less healthcare access. Studies adjust for these with varying success, and the adjusted effects are consistently smaller than the raw ones.

The absolute numbers are moderate. A relative risk increase of twenty or thirty per cent on a condition that is uncommon is a small absolute change. Worth taking seriously, not worth panicking about.

The reasonable summary: a real, dose-dependent, partly-modifiable increase in risk, of a size that makes the modifiable factors worth attending to rather than a reason to quit.

What actually seems to help

In rough order of the evidence behind them:

Sleep. The most important thing by a distance, and the one most often neglected. Consistent, dark, protected day sleep is the intervention with the strongest case. The practical version is here.

Meal timing. Eating during the biological night appears to be metabolically worse than eating the same food during the day. Shifting the main meal to before the shift, and keeping the overnight intake small, is a commonly recommended and low-cost change.

Not accumulating unnecessary night years. The dose-dependence cuts both ways. Rotating off nights for a period, or taking a day post when one is available, reduces the total exposure — and total exposure is what the risk tracks.

Exercise. Protective generally, and shift workers do less of it than average. Anchoring it to the rotation rather than to weekdays is what makes it survive.

Actually using healthcare. Shift workers use preventive services less, largely because everything is open when they are asleep. Given the elevated baseline risk, this is the wrong way round — and it is a solvable logistics problem rather than a health one.

The things that creep up

From people who have done twenty years, the effects that arrive gradually rather than dramatically:

Sleep gets worse. Many long-term night workers report that day sleep becomes harder over time rather than easier.

Social life narrows. Not suddenly. Invitations reduce, then friendships thin, then the social circle is mostly colleagues. Reversible, and much easier to prevent than repair.

Recovery takes longer. A block that was manageable at twenty-five is harder at forty-five, and people often notice this several years after it started being true.

It becomes hard to leave. Night premiums are built into a household budget, and a day post is a pay cut. This is the trap that keeps people on nights longer than they intended, and it is worth seeing coming.

Questions worth asking yourself

Every few years rather than never:

• How many years of nights have I done, and how many do I intend to do?
• Is my sleep worse than it was? Is that gradual or has something changed?
• When did I last see a GP for something that was not urgent?
• Am I on nights because I want the pattern, or because I need the premium?
• Do I still have friendships outside work?

None of them have right answers. The point is that long-term night work drifts — nobody decides to do twenty years — and the drift is easier to correct early than late.