Blood sugar: what the numbers mean and what to do

Blood sugar (blood glucose) is the energy in your blood your body uses every day. Keep it too high or too low and you feel off — tired, shaky, confused, or thirsty. Knowing the basic numbers and a few quick actions gives you control without stress.

Normal targets vary by test: fasting blood sugar is usually 70–99 mg/dL (3.9–5.5 mmol/L). Before meals many aim for 80–130 mg/dL (4.4–7.2 mmol/L). Two hours after eating under 140 mg/dL (7.8 mmol/L) is a common goal for people without diabetes; targets can differ if you have diabetes. Ask your clinician for personalized ranges.

Spotting highs and lows — and quick fixes

Low blood sugar (hypoglycemia) often hits fast. Look for sweating, shaking, hunger, lightheadedness, blurred vision, irritability, or confusion. If you suspect low blood sugar and can swallow, eat 15–20 grams of fast-acting carbs: 4 glucose tablets, 4 ounces (120 ml) fruit juice, or 1 tablespoon of sugar or honey. Wait 15 minutes and recheck. If symptoms don’t improve, repeat and call for help if needed.

High blood sugar (hyperglycemia) may cause thirst, frequent urination, blurry vision, fatigue, and slow wound healing. If you’re very high and feel sick (nausea, deep rapid breathing, abdominal pain), test for ketones and get medical help — that could be diabetic ketoacidosis, which needs urgent care. For routine highs: drink water, walk for 10–20 minutes if safe, and follow your treatment plan (insulin or meds) as advised by your provider.

Everyday habits that actually move the needle

Small daily habits add up. Focus on consistent carbs: spread them through the day instead of big spikes. Pick whole grains, beans, vegetables, and fruit over sugary drinks and sweets. Add fiber and protein to meals to slow sugar absorption — for example, pair an apple with peanut butter or have Greek yogurt with berries.

Move regularly. A 20–30 minute brisk walk after meals helps lower post-meal glucose. Strength training two times a week improves how your body uses sugar. Sleep and stress matter: poor sleep and high stress raise blood sugar for many people, so aim for regular sleep and simple stress tools like breathing or short walks.

Check your numbers in a way that informs action. Use a glucose meter or continuous glucose monitor (CGM) if recommended. Keep a simple log — time, number, what you ate, and how you felt. That helps spot patterns faster than guessing. Take medicines exactly as prescribed and review results with your clinician regularly.

If you aren’t sure what your targets should be, or you’re often high or low, schedule a visit. Quick tweaks to meds, meal timing, or activity often fix patterns. And always have a plan for low blood sugar: carry a fast-carb source and tell people close to you what to do if you can’t treat yourself.