Bloodwork for lifters: tests, ranges and timing

Sensible routine blood tests for hard-training adults, what a result outside the range does and does not mean, and how to avoid misleading numbers.

Routine blood tests are a useful health check, but they are easy to misread if you train hard. Heavy lifting, a lot of muscle and some supplements can all push certain markers outside the normal range without anything being wrong. This guide covers sensible tests, how to read the results, and how to prepare so your numbers mean something. It is general information, not a diagnosis: your doctor interprets your results.

Sensible routine tests

For a healthy adult who trains, these cover most of what a general check looks at. Ask your GP which suit you.

• Full blood count (FBC). Red cells, haemoglobin, white cells and platelets. Picks up things like anaemia.
• Lipids. Total cholesterol, HDL, non-HDL and triglycerides. Fasting is usually not needed ^[7]. See cholesterol for lifters.
• Glucose or HbA1c. HbA1c reflects average blood sugar over recent months. An HbA1c of 48 mmol/mol (6.5%) or above is the cut-off for diagnosing diabetes, and 42 to 47 mmol/mol suggests a raised risk ^[6].
• Kidney function. Creatinine and eGFR (an estimate of kidney filtering).
• Liver function. Usually includes ALT, AST, ALP, bilirubin, GGT and albumin ^[10].

In the UK, the NHS Health Check for people aged 40 to 74 includes cholesterol and blood pressure, and may add kidney and diabetes tests depending on the first results ^[9].

Reading reference ranges

Each result is shown next to a reference range. Two things to know:

• Ranges differ between labs. Always compare your result with the range printed on your own report, not one from the internet or a different lab ^{[1, 10]}.
• Outside the range is not automatically a problem. Reference ranges are standardised and will not apply to everyone, and a result outside the range may not indicate a problem ^[1]. Your doctor reads it in context with your other results, symptoms and history ^[1].

A single slightly high or low value is usually worth repeating rather than worrying about. A trend over several tests is more useful than one number.

How training and creatine skew results

This is where lifters get caught out.

Creatinine and kidney function

Creatinine is a waste product from muscle, and kidney function estimates (eGFR) are based on it. The US National Kidney Foundation lists several things that can raise blood creatinine and make kidney function look worse than it is: taking creatine supplements, recent high-intensity exercise, high muscle mass and eating large amounts of cooked meat ^[3]. If your creatinine is a bit high, tell your doctor you train hard and whether you take creatine. They may repeat the test or use a different kidney test.

CK, ALT and AST

Creatine kinase (CK) leaks from muscle after hard work. Strenuous exercise is a recognised cause of a raised CK ^[4], and intensive exercise can push it to roughly 30 times the upper limit of normal ^[5].

ALT and AST are usually thought of as liver tests, but muscle releases them too. In a study of 15 healthy men not used to weight training, one session raised AST, ALT, CK and other muscle markers, and they stayed raised for at least 7 days. The authors advised that intensive weightlifting should be considered when liver tests are unexpectedly high, and that it should be restricted before tests ^[2].

Testing conditions

To get numbers that reflect your normal health:

1. Avoid hard or unfamiliar training for several days before the test where you can, especially big leg sessions or a new programme. Plan the test after a rest day or during a deload.
2. Tell the doctor or nurse that you lift, roughly how much muscle you carry, and any supplements such as creatine.
3. Follow the lab's instructions on fasting. Some tests, such as a fasting lipid profile, need it, and most routine cholesterol tests do not ^[7].
4. Test at a similar time of day and in similar conditions each time, so results are comparable.
5. Drink normally. Do not try to dilute or "flush" results.

If you are on TRT

Testosterone therapy needs its own monitoring. Testosterone product labels advise periodic checks of testosterone levels, PSA, haemoglobin, haematocrit, liver function tests and lipids, with haematocrit checked before starting, again 3 to 6 months after, and then yearly ^[8]. Your prescriber sets the schedule. See the testosterone library page and discuss any result with your doctor.

When to see a doctor

See your GP about any result flagged as abnormal, even if you think training explains it. Your doctor may simply repeat it after rest. Get urgent medical help for dark or cola-coloured urine with severe muscle pain or swelling after training, or for chest pain, fainting or severe breathlessness.

Tracking it in ETS

ETS stores your blood test results and charts each marker over time, with alert ranges you can set from your lab report. Because your training log sits in the same app, you can see whether a high CK or creatinine came after a hard session, and plan your next test after a rest day or deload week. Logged medications and supplements are there to show your doctor.

Sources

1. Haxby Group Hull (NHS GP practice). Understanding your test results (patient leaflet). 2025. Haxby Group leaflet (PDF)
2. Pettersson J, et al. Muscular exercise can cause highly pathological liver function tests in healthy men. British Journal of Clinical Pharmacology, 2008. British Pharmacological Society
3. National Kidney Foundation. Creatinine. NKF, updated 2023. NKF: creatinine
4. Gloucestershire Hospitals NHS Foundation Trust. Creatine kinase (CK): pathology test information. Gloucestershire Hospitals: CK
5. North Bristol NHS Trust, Department of Clinical Biochemistry. Investigation of elevated creatine kinase (protocol). North Bristol NHS Trust (PDF)
6. Diabetes UK. Diagnostic criteria for diabetes. Diabetes UK. Diabetes UK
7. NHS. High cholesterol: cholesterol levels. NHS website. NHS: cholesterol levels
8. US Food and Drug Administration. AndroGel 1% (testosterone gel) prescribing information. FDA, 2025. FDA label (PDF)
9. Public Health England. NHS Health Check: aged 40 to 74? (patient leaflet). PHE, 2015. NHS Health Check leaflet
10. NHS Specialist Pharmacy Service. Assessing liver function and interpreting liver blood tests. SPS, 2024. SPS

More on health for lifters

Last reviewed 7 October 2026. General information, not medical advice. Found a mistake? Email [email protected].