- Muscle is the main place your body stores and burns glucose after meals, so more (and more active) muscle means steadier blood sugar.
- From middle age, we lose muscle every decade unless we use it. Less muscle means more insulin resistance and a higher risk of falls and frailty.
- Strength training twice a week, enough protein and daily movement protect muscle at any age.
When people think about metabolic health, they usually think about fat. But muscle is just as important. Skeletal muscle makes up around a third to two-fifths of body weight and is the body’s largest “sugar sink”. After a meal, most of the glucose cleared from the blood with the help of insulin ends up in muscle, where it is burned for energy or stored as glycogen.
That makes muscle one of your best defences against insulin resistance, prediabetes and type 2 diabetes.
Why muscle matters for blood sugar
DeFronzo et al., Diabetes 1981; Volpi et al., 2004; US Physical Activity Guidelines.
Working muscles have a second advantage: when they contract, they can take up glucose even without much insulin. That is why a short walk after a meal lowers the blood sugar rise, and why exercise helps people who are already insulin resistant.
What strength training does for your metabolism
In people with type 2 diabetes, structured exercise programmes lower A1C by around 0.7 percentage points on average, and programmes that combine aerobic and strength training tend to do best.
The quiet loss of muscle
Muscle loss with age, called sarcopenia when it becomes significant, starts earlier than most people think. Without regular strength work, adults gradually lose muscle and strength from their 30s and 40s, with faster losses after 60, during illness, bed rest, or rapid weight loss. Losing weight quickly without exercise, including with weight-loss medicines, can mean losing muscle along with fat.
Low muscle strength matters well beyond blood sugar. In a study of almost 140,000 adults in 17 countries, weaker grip strength predicted a higher risk of heart disease and early death, even better than blood pressure did.
How to build and protect muscle
Work all major muscle groups: legs, hips, back, chest, shoulders and arms. Squats, wall push-ups, rows and step-ups are a great start.
Aim for 8–12 repetitions that feel hard by the last few. Add weight or repetitions as you get stronger.
Spread protein across meals. Many older adults benefit from about 1.0–1.2 g per kg of body weight a day, unless told otherwise for kidney disease.
A 10–15 minute walk after eating helps muscles soak up glucose.
Stand or walk for a few minutes every 30–60 minutes during long sitting spells.
Muscle is built during recovery. Sleep 7–9 hours and allow rest days between hard sessions.
New to strength training? Our Beginner’s Guide to Strength Training has a simple starter routine, and The Complete Guide to Protein explains how much you need and where to get it.
Safety first. If you have heart disease, diabetic eye disease, uncontrolled blood pressure, or take insulin or a sulfonylurea, check with your doctor before starting a new exercise programme, and learn how to prevent low blood sugar during exercise.
MythStrength training is only for young people or bodybuilders.
FactAdults in their 70s, 80s and beyond build muscle and strength with regular training, and gain the most in independence and blood sugar control.
Common questions
Is walking enough, or do I need weights?
Walking is excellent for blood sugar and heart health, but it does little to maintain muscle mass. Adding some form of resistance exercise twice a week, using weights, bands or your own body weight, gives the best results.
Can I build muscle while losing weight?
Yes, especially if you are new to training. Strength training plus enough protein helps make sure the weight you lose is mostly fat, not muscle, which is particularly important if you take a GLP-1 medicine.
Does muscle really burn more calories than fat?
Yes, but the difference is smaller than often claimed: each kilogram of muscle burns roughly 13 kcal a day at rest, compared with about 4–5 kcal for fat. The bigger metabolic benefit of muscle is how much glucose it can absorb and store, and how it keeps you active and independent as you age.
- Muscle is your main glucose sink; more active muscle means better insulin sensitivity.
- Muscle is lost quietly from middle age unless you use it.
- Strength train 2–3 times a week, eat enough protein and walk after meals.
- Related: Visceral fat and Fatty liver (MASLD) explained.
Sources
- DeFronzo RA, Jacot E, Jequier E, et al. The effect of insulin on the disposal of intravenous glucose: results from indirect calorimetry and hepatic and femoral venous catheterization. Diabetes. 1981;30(12):1000–1007.
- Umpierre D, Ribeiro PA, Kramer CK, et al. Physical activity advice only or structured exercise training and association with HbA1c levels in type 2 diabetes: a systematic review and meta-analysis. JAMA. 2011;305(17):1790–1799.
- Leong DP, Teo KK, Rangarajan S, et al. Prognostic value of grip strength: findings from the Prospective Urban Rural Epidemiology (PURE) study. Lancet. 2015;386(9990):266–273.
- Bauer J, Biolo G, Cederholm T, et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. J Am Med Dir Assoc. 2013;14(8):542–559.
- US Department of Health and Human Services. Physical Activity Guidelines for Americans, 2nd edition. 2018.
- Volpi E, Nazemi R, Fujita S. Muscle tissue changes with aging. Curr Opin Clin Nutr Metab Care. 2004;7(4):405–410.
This article is for general education and is not a substitute for advice from your own doctor, diabetes educator or pharmacist.