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Woman flexing muscles

Muscle health: what you need to know

29 Nov 2022

You might not think about your muscles very often but it’s important to keep them strong and healthy throughout your life. Find out how you can do just that with our guide

Written by Charlotte Haigh on February 21, 2019 Reviewed by Sammy Margo on March 7, 2019

You might only give your muscles a second thought when you get an injury in the gym, or notice your toned abs in the mirror and feel proud that your hard work’s paying off.

But your muscles have a major impact on your health throughout your life, especially as you get older.1

What exactly are muscles?

Your body has around 600 muscles, each made up of thousands of tiny fibres. Every fibre is controlled by a nerve, which makes it contract. The strength of a muscle depends on how many fibres it contains.2 There are different types of muscle, including smooth or involuntary muscle in parts of your body, like your intestines. But generally, when we talk about muscle, we mean skeletal muscle that moves the external parts of your body, such as your limbs and face.3

There are two different fibres found in skeletal muscle, and most of your muscles will contain a mix of the two:

1. Slow twitch – these types of fibres contract slowly, and can work for extended periods without getting tired. They are well-suited to endurance activities, such as long-distance cycling.4

2. Fast twitch  – these fibres contract in short bursts. They’re perfect for fast movements, such as jumping or moving your eyes up or down, but they tire very quickly.5

Why muscles matter

Strong muscles can help:6-9
  • prevent falls and injuries, as they help keep you stable and upright
  • strengthen bones when they pull against them, reducing your risk of osteoporosis
  • maintain a healthy weight, as strong muscles help rev up your metabolism
  • protect your heart health by helping to regulate cholesterol levels

What causes muscle pain after exercise?

If you’ve been to a particularly challenging exercise class, you’ll be familiar with DOMS – delayed onset muscle soreness – which happens when you move your muscles in a different or more intense way, resulting in microtrauma to the fibres.

The soreness passes after three to five days, and you can help it along with ice packs, rest and massage. DOMS is a natural process that leads to increased strength as your muscles recover and rebuild.10 While soreness after exercise is normal, a more severe pain that may affect your movement is likely down to a muscle tear. Self-care – such as rest and ice packs – will usually help but see your doctor if the pain is very severe or doesn’t ease.11

How to look after your muscles

As we get older, our muscle mass can decline if we don’t take steps to protect it; we naturally start to lose muscle after the age of 25. By the time we’re 65 or older, 10-20% of us have low skeletal muscle function and mass, known medically as sarcopenia.12 And poor muscle strength may be on the rise – a 2018 study even revealed 10-year-olds have lower muscle strength than kids of that age 16 years earlier.13

Fortunately, there are lots of ways to safeguard muscle strength throughout your life:

1. Focus on making your muscles work harder in everyday life – this will help increase their strength, size and power. So, climb stairs, carry heavy shopping, walk up hills, and dig the garden14

2. Do resistance exercise  – it will help your muscles generate more force. Use weights, bands or your own body weight as resistance, for example push-ups, squats and yoga 15,16

3. Eat right – a balanced diet, with wholegrains for carbs, different proteins and fruit and vegetables, gives your muscles the building blocks they need to stay strong17

4. Consider protein supplements – protein supplements, like whey protein, probably aren’t necessary when you’re new to exercise, but a 2015 study in Sports Medicine reported that they can enhance muscle mass and performance once the duration, frequency and volume of resistance training increases18

5. Get enough vitamin D – a 2018 Australian review found that severe deficiency of vitamin D is linked to reduced muscle mass and weakness.19 We get it from sunlight and certain foods, like oily fish, but in the UK winter months, the government advises everyone to take a supplement.

Shop Vitamins & Supplements Advice is for information only and should not replace medical care. Please check with your GP before trying any remedies.


1. Harvard Health Publishing. 5 tips to build muscle strength 2. Christian Nordqvist. Medical News Today. Muscles: why are they important?

3. As above

4. BBC Science. Muscles – slow and fast twitch

5. As above
6. As Source 1

7. National Institutes of Health. How does physical activity help build healthy bones? 8. Riechman SE, et al. Cholesterol and skeletal muscle health

9. As above

10. NHS. Why do I feel pain after exercise? 11. Ann Pietrangelo and Kristeen Cherney. Healthline. Muscle strains 12. Piasecki M, et al. Failure to expand the motor unit size to compensate for declining motor unit numbers distinguishes sarcopenic from non‐sarcopenic older men 13. Sandercock G, Cohen DD. Temporal trends in muscular fitness of English 10-year-olds 1998-2014: An allometric approach 14. NHS. How to Improve your strength and flexibility

15. As above
16. As Source 1
17. As Source 16

18. Pasiakos SM, McLellan TM, Lieberman HR. The effects of protein supplements on muscle mass, strength, and aerobic and anaerobic power in healthy adults: a systematic review 19. Gunton JE, Girgis CM. Vitamin D and muscle