Have you ever felt shaky or weak after a workout and wondered why? Is it a good sign or a bad sign? Well, according to research published in the ‘Seminars in neurology journal, shaking/tremors after any form of intense exercise is a common occurrence and usually is nothing to be concerned about.1 There are many reasons why we may experience shaking after exercise, with some reasons more common than others. Whilst shaking is typically nothing to be concerned about, in certain cases, it can indicate poor lifestyle choices or even a more severe health condition. The following article takes a deep dive into what’s normal, not normal and when you should seek medical help.
What Causes Us to Shake After a workout?
Experiencing shaking after a workout can be attributed to a wide range of reasons, many of which are completely natural or easily fixed. Below are some of the most common causes of shaking after a workout.
Muscle fatigue is one of the most common causes of shaking after a workout. When performing any sort of movement, our central nervous system sends signals (via motor neurons) to force our muscles to contract and relax.2 During particularly strenuous workouts, the rate at which these motor neurons fire begins to slow down and become less intense as we fatigue. Consequently, our muscles begin to contract and relax much quicker, causing them to shake.
Muscular endurance exercises are any form of exercise that require a muscle or group of muscles to continuously contract against some form of force for a prolonged period of time.3 Examples include planks, wall sits or holding a heavy weight. During muscular endurance-based exercises the muscle nerves and fibres are pushed to their endurance limits. Shaking is a very common sign of a muscle being pushed towards its endurance limits and is therefore nothing to be concerned about.
Low Blood Sugar
Whilst less common than some of the factors on this list, shaking is a very common symptom of low blood sugar, making it a potential reason for an individual’s post-workout shakes. During exercise, we use carbohydrates (sugar) as a fuel source. After exercising for a prolonged period of time, our carbohydrate stores become extremely limited, causing us to experience hypoglycemia (low blood sugar), and as a consequence, shaking.
The NHS recommends between 6-9 hours of sleep a night to help your body fully recover and rejuvenate itself.4 Consistently failing to get a good night sleep has a negative effect on our central nervous system and anxiety levels, both of which can contribute to experiencing shaking. However, research has found that a lack of sleep combined with physical activity can further increase an individual’s risk of shaking, making sleep deprivation another possible culprit for your post-workout shakes.5
When we work hard during an exercise session, our body naturally begins to sweat. Whilst sweating is an integral part of core body temperature control during exercise, it causes us to lose a lot of water, making us dehydrated. When dehydrated, our electrolyte levels (salts and minerals responsible for nerve and muscle function) become unbalanced.6 Consequently, our muscle and nerve function become adversely affected, causing both muscle spasms, cramps and twitching.
High Caffeine Intake
Consuming too much caffeine could also be the cause of your shaking muscles. Once consumed, caffeine stimulates our central nervous system, hence why we feel so energised after drinking a coffee or a fizzy drink. However, in some cases, consuming too much caffeine can cause us to become overly energised, jittery and experience shaking, particularly in the hands.
Ways to reduce shaking during and after a workout
In some cases, shaking after exercise is a natural occurrence and therefore is difficult to avoid. However, there are certain things we can do to help reduce the feeling of shakiness and weakness after a workout. Below are some of the methods proven most effective in reducing post-workout shaking.
Similar to filling your car up with fuel before a long journey, it is important to consume a healthy pre-workout meal, so your body has fuel to burn during your workout sessions. It is recommended to consume a healthy and balanced meal, meaning a meal high in carbohydrates (not high in sugar), moderate in protein and low in fat, 2-3 hours before your session.
It is also vital to consume a meal within two hours of your workout to help your body replace the carbohydrates, fats and proteins lost during exercise and begin the recovery process. It is recommended to consume some form of whey protein (most likely from a protein shake or bar) within 40 minutes of finishing your session to begin protein synthesis and muscle recovery as soon as possible.
Staying hydrated before, during and after exercise is also vital to prevent muscle shaking. NHS recommends drinking at least 6-8 glasses of water a day to help you maintain optimum levels of hydration.7
Warm-up and cool down
Incorporate a 10-minute warm-up and cool down before and after your exercise sessions. Warming up before a session prepares your body and muscles for the session ahead, reducing the risk of injury. Completing a cool down helps clear the muscles of toxins and begin the recovery process, therefore reducing the risk of shaking.
Allowing your body to recover is important. Alongside a healthy and balanced diet, rest and recovery are ways to allow your muscles to properly recover from the previous session, reducing the risk of shaking as well as muscle injuries.
When to seek medical help
Whilst most instances of shaking after a workout aren’t considered serious, some individuals may require medical attention. If you experience any of the following symptoms, make sure to book an appointment with your healthcare provider.
- Shaking persists after you have rested and recovered
- Dizziness/loss of consciousness
- Breathing difficulties
- Feel nauseous/vomiting
In most cases, shaking during and after a workout is a natural occurrence and is nothing to worry about. To reduce the feeling of shakiness after your exercise sessions, ensure to consume a healthy and balanced diet, drink plenty of fluids and give your muscles an adequate amount of time to recover in between your sessions. If shakiness persists long after your session and/or is accompanied by some of the aforementioned more severe symptoms, ensure to book an appointment with your healthcare provider.
- Puschmann A, Wszolek ZK. Diagnosis and treatment of common forms of tremor. Semin Neurol [Internet]. 2011 Feb [cited 2022 Jul 28];31(1):65–77. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3907068/
- Son H, Kim J, Hong G, Park W, Yoon S, Lim K, et al. Analyses of physiological wrist tremor with increased muscle activity during bench press exercise. J Exerc Nutrition Biochem [Internet]. 2019 Mar 31 [cited 2022 Jul 28];23(1):1–6. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6477828/
- Kell RT, Bell G, Quinney A. Musculoskeletal fitness, health outcomes and quality of life. Sports Med. 2001;31(12):863–73.
- Sleep [Internet]. NHS Services London England UK - find local help now! [cited 2022 Jul 28]. Available from: https://myhealth.london.nhs.uk/self-care/sleep/
- Tomczak A, Gajewski J, Mazur–Różycka J. Changes in physiological tremor resulting from sleep deprivation under conditions of increasing fatigue during prolonged military training. Biol Sport [Internet]. 2014 Dec [cited 2022 Jul 28];31(4):303–8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4296843/
- Dehydration - Symptoms and causes [Internet]. Mayo Clinic. [cited 2022 Jul 28]. Available from: https://www.mayoclinic.org/diseases-conditions/dehydration/symptoms-causes/syc-203540867.
- Water, drinks and your health [Internet]. nhs.uk. 2022 [cited 2022 Jul 28]. Available from: https://www.nhs.uk/live-well/eat-well/food-guidelines-and-food-labels/water-drinks-nutrition/