Staying active is vital for overall health. It is also the best way to build muscle. How long it takes to grow muscle through activity varies from person to person, but there are guidelines that can help maximize individual gains.

The best way a person can improve their muscle mass involves engaging in the right exercises and eating the right foods. Skeletal muscles are major muscle types, and when we talk about building muscle, we are referring to skeletal muscle mass.

Fast facts on building muscle:

  • Skeletal muscles grow through being progressively overloaded.
  • Muscle growth occurs at different rates in men and women.
  • Strength training has an almost immediate effect on muscles, with protein synthesis, which aids muscle growth, starting within 2-4 hours of working out.
  • Aging can decrease muscle mass, but regular resistance exercise may stop or even reverse this muscle loss.

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Regular strength training is one of the quickest and most effective ways to build muscle.

By continually challenging the muscles to deal with greater levels of resistance or weight, a person will see their muscles increase in size in a process known as muscle hypertrophy.

Muscle hypertrophy occurs when the fibers within the muscles are injured or damaged. The body repairs damaged fibers by fusing them together, thereby increasing the mass and size of the muscles.

Some research suggests that satellite cell activation may determine how rapidly and how much muscle an individual can grow.

Hormones, such as testosterone, human growth hormone, and insulin growth factor, also play a role in muscle growth and repair. These hormones:

  • increase protein synthesis
  • inhibit protein breakdown
  • activate satellite cells
  • stimulate anabolic hormones
  • enhance tissue growth

Strength and resistance training can help to release growth hormone from the pituitary gland, stimulate testosterone release, and improve the sensitivity of muscles to testosterone.

Muscle growth in men and women

While research suggests that both sexes can build muscle through strength training, women tend to build muscle more slowly than men.

Other factors also play a role in muscle growth in both men and women. Those who have greater muscle mass at the outset will experience quicker and more noticeable changes in their muscles. Hormone levels, age, and body size also play a role.

It should also be noted that, as the body builds more muscle, the rate at which it does so slows down.

People build muscle at different rates, but the chances of building muscle are greatly increased if exercise is:

  • consistent
  • challenging
  • long-term
  • followed by enough rest

The best type of exercise to build muscle is strength training, although cardiovascular activity is also beneficial.

Strength training

Lifting weights in the gym.Share on Pinterest
Lifting free weights is a popular way to build muscle, but varying exercises is essential in order to engage all muscle groups.

It takes several weeks or months of consistent activity and exercise before muscle changes are visible.

According to the Physical Activity Guidelines for Americans 2015-2020, adults should engage in muscle-strengthening exercises that involve all major muscle groups at least twice weekly.

Examples of strength training activities include:

  • lifting free weights
  • using stationary weight machines
  • resistance band activities
  • bodyweight exercises, including push-ups and squats
  • strength training classes, incorporating some or all of the above activities

Some research suggests that one set of 12 repetitions with a heavy weight can be as effective as 3 sets with a lighter weight, particularly in the early stages of exercise.

This finding is controversial though, as other studies report 46 percent greater strength gains from multiple rather than single sets.

Strength training and aging

Older adults should try to meet the adult exercise guidelines if they can. If they are unable to do this, they should be as physically active as possible given their limitations. Strength training is also beneficial for older adults to prevent injury and to aid recovery.

Cardiovascular activity

Also known as aerobic activity or simply "cardio," cardiovascular exercise benefits a person's heart and respiratory or breathing system.

Cardio is vital for overall health, with current guidelines recommending that adults participate in at least 150 minutes of moderate-intensity, or 75 minutes of vigorous-intensity, aerobic activity each week.

While some people believe that aerobic activity does not help build muscle, recent research refutes this idea. Regular cardio can aid muscle growth and function. It also increases overall fitness levels, which may help reduce the risk of injury.

For optimal muscle building, researchers say aerobic exercise training should be carried out:

  • at 70-80 percent of heart rate reserve (HRR)*
  • for 30-45 minutes at a time
  • on 4-5 days per week

*HRR is calculated by subtracting a person's resting heart rate from their maximum heart rate.

Rest plays an integral part in building muscle. Failure to give enough rest to each of the muscle groups reduces their ability to repair, slows fitness progression, and raises the risk of injury.

According to experts, strength training should not be carried out on the same muscle group for 2 consecutive days.

Getting enough sleep is also important for the process of muscle growth. Research suggests that sleep debt decreases protein synthesis, contributes to the loss of muscle mass, and reduces muscle recovery.

Reducing stress may also help in the building of muscle, as hormones released during periods of stress have a negative effect on skeletal muscle.

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Beans and lentils are good plant-based sources of protein.

Eating a balanced and healthful diet is key to staying fit. When it comes to building muscle, protein intake is especially important.

Current guidelines recommend that adults consume 0.8 grams (g) of protein per kilogram of body weight per day.

The timing of protein intake may also be of importance. A paper included in the 2013 Nestlé Nutrition Institute Workshop Series suggests that 20 g of dietary protein taken during or immediately after exercise helps to stimulate muscle protein synthesis, reduces protein breakdown, and leads to more effective muscle reconditioning.

Sources of protein include:

  • meat
  • fish
  • eggs
  • milk and cheese
  • soybeans and tofu
  • beans and lentils
  • nuts
  • seeds

The United States Department of Agriculture (USDA) online calculator can work out individual protein needs, as well as other dietary recommendations.

A fitness professional can guide people about the correct form to use when lifting weights and using other gym equipment. Using the right techniques cuts the risk of injury and enhances the potential to build muscle. Other tips for people to consider include:

  • Warm up and stretch for 5-10 minutes before engaging in strength or cardio activities.
  • Begin with light weights and increase weight or resistance level gradually.
  • Carry out exercises, using proper form, breathing techniques, and controlled movement.
  • Expect some soreness and muscle fatigue afterward, particularly in the early stages. Too much discomfort or exhaustion suggests workouts are too intense, too frequent, or too long.

It is recommended that people always consult a doctor before embarking on any new exercise regimen.