Ask the expert

Michele Watkins

Thumb muscle started to twitch

Two days ago my thumb muscle started to twitch when I relax my hand. I thought this must be due to some sort of nerve damage but when I Googled it thinking maybe I could do some sort of exercise to stop it I was horrified to find out this could be a sign of motor neurone disease! I am otherwise fit and healthy, I exercise most days, I have no loss of strength and the twitching disappears as soon as I grip something. Do you know what the cause of this could be? Am I worrying for nothing? Or should I visit the doctor? Am never going to google anything again!

1 March 2021

Thank you for contacting us. There certainly is a lot of information out there and it can be alarming when symptoms appear to indicate something serious. However, in most cases – and this is one of them – there are a number of possible causes and it’s only by taking into account a range of factors including your medical history and that of your immediate family, your lifestyle, work and so on, together with a thorough physical examination that a proper diagnosis can be made, so please try not to worry too much. 

Muscle twitching (fasciculation) at rest is not uncommon. The twitches themselves are minor involuntary muscle contractions – often occurring in the finger, eye or leg muscles – and can be caused be a variety of things. Rarely, twitching can indicate a nervous system problem, but this tends to be the exception.  

More commonly, muscle twitches at rest such as you have been noticing with your thumb recently can be associated with stress and anxiety, caffeine intake, lack of sleep, exercise (with twitching occurring after exercise), nutrient deficiencies, dehydration, and the side effects of some medications, including oestrogens. It can also sometimes indicate an electrolyte imbalance such as low potassium but this tends to be less common.

7 common reasons for muscle twitches – and how to prevent them

1. Stress and anxiety

When you’re stressed, your body goes into fight or flight mode, which has a number of physical effects on your body. These include causing nerve impulses to fire erratically, which, since nerves are responsible for muscle control, can in turn cause your muscles to twitch. Preventing these types of twitches comes from learning to manage your stress and anxiety effectively. Visit the stress pages within our mental health centre for lots of expert tips, tools and practical information to help.

2. Caffeine intake

Along with increased heartbeat, jitters and restlessness, muscle twitches are commonly associated with having too much caffeine. In this case it’s the stimulants in high amounts of caffeine that cause the small involuntary tensions in muscle fibres around the body. Again, you can find lots of tips and support to help you reduce your caffeine intake and its side effects within our health and wellbeing pages. Some good places to start include Cutting down on caffeine and 9 pick me ups that are caffeine free.

3. Lack of sleep

Muscle twitches often occur when the body is tired or sleep deprived. This is because a lack of sleep affects the messaging system that the brain uses to control body movements and can cause it to send random extra messages to the muscle fibres, resulting in a twitch. The solution is, of course, to try to get more or better quality sleep and our sleep centre is here to help. In it you’ll find a wide range of expert tips and practical tools – covering everything from sleep hygiene tips to ASMR recordings. In short, the best that science, technology and research can offer to help you sleep better.

4. Exercise

In the same way that tiredness from a lack of sleep can cause muscle twitches, so can fatigue caused by exercising. Here the solution is to ensure you’re properly fuelled and hydrated before, during and after exercise, and that you don’t overdo it! Our article on what to eat before and after exercise has more on this, or visit our Exercise and fitness centre for information on how to exercise safely.

5. Nutrient deficiencies

Poor nutrition and problems with absorbing nutrients can lead to muscle twitching. Electrolytes, which include calcium, magnesium and potassium, play a particularly important role in efficient muscle function, between them supporting muscle contractions and nerve signalling, and helping to reduce cramps and twitches. Eating a diet rich in sweet potatoes, salmon, broccoli, spinach and banana should help. Find out more about how to eat for healthy body functioning in our article Nutrition for good health.

6. Dehydration

Among other things, dehydration has the effect of reducing blood flow to working muscle fibres, which can impact on their ability to carry out normal functions, such as contacting and relaxing properly. Dehydration happens when we lose more fluid from our bodies – typically through urination, sweating (due to heat or long periods of exercise), vomiting or diarrhoea – than we take in. This lost fluid also contains electrolytes as discussed above, so it’s important to not only replace water lost but these essential elements too. Sports drinks, dioralyte medication and electrolyte-enriched bottled water can all help. Our article Are you at risk of dehydration? contains lots more ideas for keeping your body topped up with fluids.

7. Side effects of medication

Although it’s rare, some medications can cause involuntary contractions of the muscle fibres (twitches). For example, some antidepressants used in conjunction with other medications or St John’s Wort can result in an excess of serotonin in the brain, which can cause twitching. Other types of prescription medication that may cause muscle twitching include diuretics, corticosteroids or oestrogens. If you’re concerned about twitching and you’re taking medication containing any of these, it’s worth seeing your GP to check whether they are to blame and find an alternative if appropriate. As always, it’s important that you don’t just stop taking any prescribed medication without medical supervision

When to seek medical help for twitching 

Benign twitches such as those caused by the above are normal and quite common and they can tend to come and go over a period of days. It is only when twitches become more long term, lasting over a period of weeks, or are associated with a loss of sensation, muscle and weakness in the limb affected that a visit to a doctor would be advised. 

Answered by the Health at Hand team

Useful resources

Mental health centre - AXA Health

Tips for managing stress - AXA Health

Exercise and fitness centre - AXA Health

Diet and nutrition centre - AXA Health

NHS 2021, Twitching in muscles and eyes.  (Accessed 1 March 2021)

The Association of UK Dietitians (BDA) 2021. (Accessed 1 March 2021)

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