How to Read Your Cholesterol Numbers (Plain English Guide)
Your cholesterol test results come with four or five numbers. Here is what each one means — and what to do about it.
⚕️ Medical disclaimer
This article is for general educational purposes only. Always discuss your individual cholesterol results and treatment options with your GP or healthcare provider.
The four key numbers
Total Cholesterol
Target: Below 5.0 mmol/L (NHS) · Below 200 mg/dL (US)
This is the sum of all cholesterol in your blood. High total cholesterol is a risk marker, but context matters — a high total driven by high HDL is very different from one driven by high LDL. Total cholesterol alone is not sufficient to assess cardiovascular risk.
LDL — 'Bad' Cholesterol
Target: Below 3.0 mmol/L (NHS) · Below 100 mg/dL (US, optimal)
LDL (Low-Density Lipoprotein) carries cholesterol to cells, but excess LDL particles can penetrate artery walls, oxidise, and trigger inflammation — leading to atherosclerotic plaques. LDL is the primary target of statin therapy. People with cardiovascular disease or diabetes often have lower targets (below 1.8–2.0 mmol/L).
HDL — 'Good' Cholesterol
Target: Above 1.0 mmol/L men / 1.2 mmol/L women (NHS) · Above 40/50 mg/dL (US)
HDL (High-Density Lipoprotein) acts as a reverse cholesterol transport system — carrying excess cholesterol back to the liver for recycling or excretion. Higher HDL is strongly associated with lower cardiovascular risk. Exercise, moderate alcohol, and quitting smoking all raise HDL.
Triglycerides
Target: Below 1.7 mmol/L (optimal) · Below 150 mg/dL (US)
Triglycerides are fats stored in blood after meals. High triglycerides often indicate excess refined carbohydrate and sugar intake, excessive alcohol, obesity, or insulin resistance. They are an independent cardiovascular risk factor, particularly when combined with low HDL.
The Total:HDL ratio — often more useful than totals
Dividing your total cholesterol by your HDL gives a ratio that many cardiologists consider more predictive of cardiovascular risk than any individual number. A ratio below 4.0 is generally considered acceptable; below 3.5 is optimal.
Example: 5.2 ÷ 1.4 = 3.7 (acceptable)
How diet affects cholesterol
Dietary changes can meaningfully shift cholesterol values over 6–12 weeks:
- Saturated fat: The strongest dietary driver of LDL. Reducing red meat, full-fat dairy, and tropical oils typically reduces LDL by 5–15%.
- Trans fats: Raise LDL and lower HDL simultaneously — avoid processed foods with partially hydrogenated oils.
- Soluble fibre: 5–10g of soluble fibre daily (oats, legumes, psyllium) reduces LDL by approximately 5–7% by binding to cholesterol in the gut.
- Omega-3 fatty acids: Found in oily fish (salmon, mackerel, sardines), omega-3s reduce triglycerides by up to 30% and modestly raise HDL.
- Plant sterols: Found in fortified spreads and some dairy alternatives, 2–3g per day reduces LDL by 10–15%.
- Refined carbohydrates and sugar: Raise triglycerides and lower HDL. Reducing added sugar is particularly important for those with high triglycerides.
How exercise affects cholesterol
Regular aerobic exercise is the most effective lifestyle intervention for raising HDL. Studies show that 30 minutes of moderate aerobic activity (brisk walking, cycling, swimming) 5 days per week can raise HDL by 5–10%. Exercise also reduces triglycerides and modestly lowers LDL.
The type of exercise matters less than consistency — both aerobic and resistance training improve lipid profiles.
When medication is needed
Lifestyle changes can improve cholesterol significantly, but have limits. People with familial hypercholesterolaemia (FH) have genetically very high LDL (often above 7–10 mmol/L) that cannot be adequately managed through diet alone. Statins remain the most evidence-based pharmacological intervention and are generally well-tolerated.
Current NHS guidelines recommend statins for people with a 10-year cardiovascular risk above 10% (assessed using the QRISK3 tool). Your GP can assess whether medication is appropriate for your individual risk profile.