Working nights isn't just tiring. Your body clock genuinely runs your metabolism, and shift work throws it off in ways that show up in bloodwork. This isn't a matter of adjusting better.

What Nights Do to Your Body

Circadian disruption changes how you handle sugar and fat, alters cortisol, and interferes with the hormones controlling appetite and sleep. It happens whether or not you cope well with the schedule. Some people handle nights fine and their numbers still move.

There's very little daylight in a night-shift life either, so vitamin D goes the same way as any indoor job, and eating at odd hours compounds the metabolic side. The tricky part: thyroid problems, anaemia and B12 deficiency all produce exactly the exhaustion the shifts do. Testing is the only way to tell which one you're dealing with.

Who Should Consider These Tests

• You work nights or rotating shifts

• You can't sleep properly on rest days

• You've gained weight since the shifts started

• You're more wrecked than the schedule really explains

• You eat at completely random hours

• You haven't had a checkup since your pattern changed

What Each Test Tells You

This page lists 8 options. Here's what each one actually measures, so you can pick instead of guessing.

Blood tests

• Complete Blood Picture (CBP): Counts your red cells, white cells and platelets. It's the cheapest way to catch anaemia or an infection you didn't know you had, and it's the single most booked test we do.

• HbA1c: Your average sugar over the last two to three months. One good week won't fix this number, which is the point of it.

• Lipid Panel: Splits your cholesterol into the good, the bad and the triglycerides. High cholesterol has no symptoms at all, which is exactly the problem.

• Thyroid Function Tests: Checks the hormones that set how fast your body runs. Worth doing if you're tired, gaining or losing weight without trying, or your hair's thinning.

• Serum Cortisol: Your stress hormone, which runs on a daily clock that night shifts and long-term stress throw off.

• Vitamin B12 Test: Your nerves and red blood cells need B12. If you're vegetarian, you're at real risk, and the symptoms are easy to miss: tingling hands, fuzzy thinking, no energy.

• Vitamin D (25 - Hydroxy Vitamin D, Serum): Your body makes this from sunlight, and most people who work indoors don't get enough. Low levels show up as aching bones, weak muscles and flat mood.

• Master Health Checkup: Blood counts, sugar, lipids, liver, kidney, thyroid and urine bundled into one visit. Cheaper than booking the pieces separately.

How to Prepare

• No fasting: Complete Blood Picture (CBP), HbA1c, Vitamin D (25 - Hydroxy Vitamin D, Serum)

• 9 to 12 hours fasting. Water's fine: Lipid Panel, Master Health Checkup

• Morning, before 10am: Serum Cortisol

• No fasting. Take your thyroid tablet after the sample, not before: Thyroid Function Tests

• No fasting. Ask your doctor before pausing supplements: Vitamin B12 Test

Tell the collection team everything you're taking, prescription or not. Plenty of supplements move these numbers, and without that context your report reads wrong.

How Often to Repeat

Once a year minimum. Twice if you're on permanent nights or a fast rotation.

Understanding Your Results

Book after a rest period, not straight off a night shift. Both the fast and the cortisol reading depend on it, and a sample taken at 8am after a full night on is close to uninterpretable.

These tests point at a diagnosis. They don't make one. Read your report with a doctor who knows your history and what you're currently taking.