How muscles recover after exercise

Learn how muscle recovery works, why soreness happens, and how protein, carbs, sleep and magnesium support repair.

Training is only half the equation. The actual rebuilding of muscle happens in the hours and days after you stop, when the body repairs tissue, restores its energy stores, and adapts to the load it has just handled. The choices you make about food, fluids, sleep and rest between sessions shape how well that process runs.

This article walks through what happens to muscle during and after exercise, the nutrients involved in repair, and the everyday habits that support recovery.

What happens to muscles during exercise

When you train, your muscles contract repeatedly against resistance or load. This places mechanical stress on the muscle fibres and the connective tissue around them. Strength training and any unfamiliar or eccentric movement (where the muscle lengthens under tension, like the lowering phase of a squat) create small amounts of microscopic damage to the fibres.

At the same time, working muscles burn through their stored fuel. Glycogen, the form of carbohydrate held in muscle, drops during longer or harder sessions. You also lose fluid and electrolytes through sweat. None of this is a problem. It is the normal signal that tells the body to repair and adapt so it can handle the same load more easily next time.

Understanding muscle repair and adaptation

Recovery is an active rebuilding process. After exercise, the body lifts its rate of muscle protein synthesis, which is how it lays down new proteins to repair and reinforce the fibres you have worked. Specialised cells sitting alongside the muscle fibres help with this repair, fusing in to support the existing tissue.

Two things happen in parallel. Muscle protein breakdown rises for a period after training, and so does muscle protein synthesis. Recovery tips the balance towards synthesis, which is what allows muscle to repair and gradually adapt. Alongside this, the body refills muscle glycogen and restores fluid balance. This combination of repair, refuelling and rehydration is what people mean by recovery.

Why soreness happens after training

That stiff, tender feeling a day or two after a tough or unfamiliar session is known as delayed onset muscle soreness, or DOMS. A systematic review in Antioxidants describes the usual pattern: soreness begins around 12 to 24 hours after exercise, peaks between 24 and 72 hours, and eases within five to seven days.

DOMS is linked to the microscopic damage and the inflammatory response that follow eccentric or unaccustomed exercise. It is most noticeable when you try a new activity, return after a break, or increase your training load. Soreness is not a reliable measure of how good a workout was, and its absence does not mean nothing happened. It is one part of the body responding to a new demand.

The nutrients involved in muscle recovery

No single nutrient drives recovery. The body draws on several, and most are easy to cover through everyday meals.

Protein

Protein supplies the amino acids the body uses to repair and rebuild muscle. Spreading protein across the day, rather than loading it all into one meal, gives the muscles a steadier supply of these building blocks.

A systematic review and meta-analysis in the European Journal of Clinical Nutrition found that protein supplementation around resistance exercise helped preserve muscle strength and lowered markers of muscle damage in the days afterwards. The same review found that protein did not reduce muscle soreness, which is a useful reminder that food supports the underlying repair even when it does not change how sore you feel.

Carbohydrates

Carbohydrates refill the glycogen used during training. After longer or more intense sessions, including some carbohydrate alongside protein helps restore that fuel so you are ready for the next session. Wholegrains, fruit, legumes and starchy vegetables all contribute.

Fluids and electrolytes

Rehydrating after exercise restores the fluid lost through sweat and supports normal circulation, which carries nutrients to the muscles. Electrolytes such as sodium, potassium and magnesium are lost in sweat and play a part in fluid balance and muscle function.

Magnesium and other minerals

Magnesium is one of several minerals involved in how muscles work, which is why it often comes up in conversations about recovery. The next section looks at its role in more detail.

The role of magnesium in muscle recovery

Magnesium is an essential mineral and a cofactor in energy production. It is involved in muscle contraction and relaxation, nervous system function and the body's electrolyte balance. Because these processes all sit close to how muscle works during and after exercise, magnesium has become a common focus of recovery research.

A systematic review in the Journal of Translational Medicine examined magnesium supplementation and muscle soreness across different types of physical activity. It reported modest reductions in soreness ratings and better recovery measures, with the clearest signal in people who started with low magnesium levels. The review included only a limited number of small trials and called for larger trials, so the evidence is still developing.

That pattern, where the benefit shows up mainly in people with low intake, fits what we know about magnesium generally. It supports normal function when your levels are adequate, and topping up matters most when dietary intake falls short. According to the Australian Bureau of Statistics, 31% of Australians did not meet their magnesium requirement from food in 2023, so a shortfall is common.

Food sources of recovery nutrients

Whole foods cover most of what recovery needs. A practical approach is to build meals around protein, include some quality carbohydrate, and add plenty of plants.

For protein, good options include lean meat, poultry, fish, eggs, dairy, tofu, legumes and nuts. For carbohydrate and glycogen replacement, wholegrains, oats, rice, potatoes, fruit and legumes all work well.

Magnesium is found across many everyday foods. Green leafy vegetables, legumes, nuts, seeds and wholegrains are reliable sources, and you can find more in this guide to magnesium rich foods. Eating a varied diet across the week is the simplest way to cover magnesium alongside the other minerals lost through sweat.

Hydration, sleep and recovery

Rehydrating after a session restores fluid balance and supports the delivery of nutrients to working muscles. Drinking to thirst across the day, and a little more after heavy sweating, covers most people's needs.

Sleep is one of the most underrated parts of recovery. Much of the body's repair activity, including the release of growth hormone, happens during deep sleep. A study in young healthy men published in Physiological Reports found that a single night of total sleep deprivation reduced muscle protein synthesis by 18 per cent the following day. Regular, sufficient sleep gives the body the window it needs to rebuild between sessions.

Recovery timelines: what to expect

Recovery is not the same for everyone, and the timeframe depends on the session, your training history and your overall lifestyle. Muscle protein synthesis, the process behind repair, stays elevated for up to around 48 hours after a resistance session, according to a review in Frontiers in Physiology. This is part of why many people allow roughly 48 to 72 hours before training the same muscle group hard again.

Lighter or familiar sessions need less recovery than heavy or unfamiliar ones. Sleep, nutrition, age and stress all influence how quickly you bounce back, so it helps to judge readiness by how you feel and perform rather than the clock alone.

Common mistakes that slow recovery

A few habits tend to work against recovery:

• Under fuelling, particularly not eating enough protein or total energy to support repair
• Cutting sleep short on a regular basis
• Skipping rest days and training the same muscles hard before they have recovered
• Starting the next session already dehydrated
• Relying on supplements while overlooking the basics of food, fluids and sleep

Addressing these everyday factors usually does more for recovery than any single product.

Supplementation considerations

A balanced diet covers recovery for most people. Supplements can have a place when dietary intake is low or when meeting needs through food alone is difficult.

Magnesium is one example. If your magnesium intake from food is consistently low, a supplement can help top up your levels. You can compare options across the Blackmores magnesium range, which comes in different forms and strengths. If you choose to use a supplement, it's important to follow the directions for use on the label.

Blackmores Magnesium Glycinate contains magnesium in the glycinate form, providing 150 mg of magnesium per tablet. Magnesium contributes to normal muscle function, supports muscle relaxation and nervous system function, and helps relieve muscle cramps and mild muscle spasms when dietary intake is inadequate. It also supports healthy sleeping patterns and body electrolyte balance. Vitamins and minerals can only be of assistance if dietary intake is inadequate, and a supplement works alongside a balanced diet rather than replacing it.

Building a recovery routine

A workable recovery routine does not need to be complicated:

• Eat a meal with protein and some carbohydrate after training
• Spread protein across your meals through the day
• Rehydrate after sessions, especially heavy or hot ones
• Aim for consistent, sufficient sleep
• Leave enough time between hard sessions for the same muscle group
• Include a mix of plant foods across the week to cover minerals like magnesium

Consistency over weeks matters more than getting any single day perfect.

When to see a healthcare professional

Most post exercise soreness settles on its own. Some situations are worth a conversation with a professional. See your GP or another qualified healthcare professional if you have sharp or sudden pain during exercise, soreness that does not ease after several days, noticeable swelling, muscle weakness that lingers, or recurring cramps that disrupt daily life. A professional can help identify the cause and tailor advice to your circumstances, particularly if you have an existing condition or take regular medication.

Frequently asked questions

How do muscles recover after exercise?

The body repairs the small amount of damage to muscle fibres, refills the glycogen used as fuel, and restores fluid balance. This happens over the hours and days after a session, supported by food, fluids and sleep.

How long does muscle recovery take?

It depends on the session and the person. Soreness from a tough or unfamiliar workout usually peaks within 24 to 72 hours, then eases. Many people leave 48 to 72 hours before training the same muscle group hard again.

What helps muscles recover faster?

The basics do most of the work: enough protein and total energy, some carbohydrate to refill glycogen, good hydration, and consistent sleep.

Does protein help with muscle recovery?

Yes. Protein supplies the amino acids the body uses to repair and rebuild muscle. Spreading it across your meals gives muscles a steadier supply through the day.

Does magnesium help muscle recovery?

Magnesium plays a part in muscle function, the nervous system and electrolyte balance. The benefit for recovery appears clearest in people whose magnesium intake is low, and it can only be of assistance when dietary intake is inadequate.

Do I need supplements for muscle recovery?

Most people can support recovery through a balanced diet, fluids and sleep. Supplements help fill a genuine gap, such as a low magnesium intake, rather than replacing the everyday basics.

Key takeaways

Muscle recovery is an active process of repair, refuelling and rehydration that happens after you train, not during. Protein supports the rebuilding of muscle, carbohydrate refills glycogen, fluids restore balance, and sleep provides the main window for repair.

Magnesium is one of several minerals involved in muscle function, and its benefit for recovery appears clearest in people whose intake is low. Around 31% of Australians fall short of their magnesium requirement from food, so covering it through a varied diet matters. A supplement can help when dietary intake is inadequate, alongside the everyday habits that do most of the work.

Always read the label and follow the directions for use.

Disclaimer: This article provides general information only and is not intended to diagnose, treat, cure, or prevent any disease. The information presented is not a substitute for professional medical advice. If you have concerns about your health, please consult your GP or healthcare provider for a personalised assessment and recommendations. Supplements should not replace a balanced diet.