If your smartwatch or a fingertip device has ever flashed a number like “98%” at you, that’s your blood oxygen level — and it’s a quick window into how well your body is being supplied with oxygen. But what counts as a normal SpO2 reading, when is it too low, and how much should you…
Your blood sugar level is one of the most important — and most misunderstood — numbers in your health. Millions of people have prediabetes and don’t know it, because it usually causes no symptoms at all. So what is a normal blood sugar level, what does your HbA1c mean, and when do the numbers signal…
A cholesterol test gives you four numbers — and most people have no idea which ones they want high and which they want low. (Yes, one type is actually good for you.) So what is a healthy cholesterol level, what do LDL, HDL, and triglycerides mean, and when should your numbers worry you? Let’s decode…
Vitamin B12 deficiency is surprisingly common — and surprisingly easy to miss. Its symptoms creep in slowly and look like everyday tiredness, yet left untreated it can cause lasting nerve damage. So how do you know if you’re low, what’s a normal B12 level, and what should you do about it? Let’s decode it. What…
TSH is the single most common thyroid test — and one of the most confusing numbers in medicine. The biggest source of confusion? A high TSH usually means an underactive thyroid, not an overactive one. If that seems backwards, you’re not alone. Let’s decode what your TSH level really means. What is TSH? TSH stands…
Ferritin is one of the most useful — and most overlooked — numbers on a blood test. It’s essentially your body’s iron savings account, and when it runs low, you can feel exhausted long before a standard blood count shows anything wrong. So what does low ferritin mean, what are the symptoms, and what counts…
Vitamin D — the “sunshine vitamin” — is one of the most common deficiencies in the world, affecting an estimated one billion people. Yet its symptoms are so vague that most people never connect the dots. So how do you know if you’re low, what is an optimal vitamin D level, and how can you…
Blood pressure is one of the most important numbers your body produces — yet most people have no idea whether their reading is healthy. It quietly shapes your risk of heart attack, stroke, and kidney disease, often without a single symptom. So what is a normal blood pressure by age, what do the two numbers…
Your resting heart rate is one of the simplest — and most revealing — numbers your body gives you. With a finger on your wrist or a glance at your smartwatch, you get an instant clue about how hard your heart is working and how fit you are. But what counts as a normal resting…