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The importance of sleep for muscle growth

by Harry 6 minutes read

Last updated: 31 Jul, 2023

In the world of fitness, building muscle is a primary goal for many gym-goers. Hours at the gym, balanced diets, and the right supplements all play crucial roles in the process of muscle growth. But, one aspect regularly underestimated that can significantly impact muscle gain is sleep.

In this article, we will delve into the vital importance of sleep for muscle growth and explore the science behind this often underrated aspect of fitness.

The Basics of Muscle Growth

Muscle growth, also known as muscle hypertrophy, occurs when muscle fibres are broken down during exercise with what are called 'micro-tears'. These micro-tears are small tears in the fibres of the muscle which are repaired by the body. By repairing the tears or 'gaps' created in the muscle fibres, over time, the muscle becomes larger and stronger than before.

Perhaps the most important point to remember with muscle growth, is that it only happens during rest. You aren't increasing muscle mass while you work out, instead you are creating these micro-tears and while you rest, your body is using the nutrients you provide it to repair the muscle fibres, and that's where the growth comes from.

The main nutrients your body needs to repair muscle, are:

  • Protein: Protein is the most crucial nutrient for muscle growth as muscles are primarily made up of protein fibres. Protein provides the necessary amino acids, the building blocks of muscle tissue, which are used for muscle repair and growth after exercise.

  • Carbohydrates: Carbohydrates are essential for providing energy during workouts and replenishing glycogen stores in muscles post-exercise.

  • Fats: Healthy fats are crucial for hormone production, including testosterone, which plays a role in muscle growth.

  • BCAAs (Branched-Chain Amino Acids): BCAAs, which include leucine, isoleucine, and valine, are a subset of essential amino acids. They are particularly important for muscle growth and recovery, as they are readily used by the muscles during and after exercise.

The Basics of Sleep

The amount of sleep needed varies depending on age, lifestyle, and individual factors. The National Sleep Foundation and American Academy of Sleep Medicine's research suggests general guidelines for sleep durations based on age groups. Here are the general guidelines:

  • Newborns (0-3 months): 14-17 hours per day

  • Infants (4-11 months): 12-15 hours per day

  • Toddlers (1-2 years): 11-14 hours per day

  • Preschoolers (3-5 years): 10-13 hours per day

  • School-age children (6-13 years): 9-11 hours per day

  • Teenagers (14-17 years): 8-10 hours per day

  • Young adults (18-25 years): 7-9 hours per day

  • Adults (26-64 years): 7-9 hours per day

  • Older adults (65+ years): 7-9 hours per day

So, for everyone aged over 18, 7-9 hours of sleep time per day is ideal, but this can vary depending on the individual.

The Importance of Sleep for Muscle Growth

There are a range of ways that the amount and quality of sleep will affect your muscle growth. Here a few of the key things to remember:

Hormonal Balance

Several key hormones, including the human growth hormone (HGH), testosterone, and insulin-like growth factor 1 (IGF-1), play important roles in muscle growth. Studies have consistently shown that a significant proportion of these hormones are released during deep sleep. HGH in particular, is released in its highest amounts during the first few hours of sleep, promoting tissue repair and muscle growth.

Testosterone, the primary male sex hormone that also influences muscle growth, is at its peak level during early morning sleep. Sleep deprivation can disrupt this hormonal balance, leading to potential reductions in growth hormone and testosterone secretion, and therefore lowering muscle growth potential.

Muscle Recovery and Repair

Sleep is a period of crucial rest and repair for the entire body, including your muscles. During deep sleep, blood flow to muscles increases, delivering essential nutrients and oxygen needed for proper recovery.

Crucially, the body uses this time for the synthesis of proteins, which are the building blocks of muscle tissue. A good night's sleep allows these processes to occur optimally, enhancing muscle repair and growth.

Reduced Cortisol Levels

Cortisol, otherwise known as the stress hormone, can have a huge effect on muscle tissue when present in high amounts. Lack of sleep or poor sleep quality has been linked to elevated cortisol levels. Consistent elevation of cortisol can lead to increased muscle breakdown and decreased muscle protein synthesis, hindering muscle growth progress.

Energy Levels

Adequate sleep plays a vital role in replenishing energy levels and optimising your performance during exercise. A well-rested body is better equipped to perform at its peak during workouts, enabling more intense and effective training sessions. If you can train with higher intensity and effectiveness, you can create more micro tears in your muscle fibres and therefore create an opportunity for more growth.

REM Sleep

Rapid Eye Movement (REM) sleep, a phase of deep sleep, is also essential for muscle memory consolidation. During REM sleep, the brain processes and stores information from the day's activities, including motor skills learned during exercise. Proper consolidation of muscle memory helps to improve performance and technique, improving the quality of future workouts.

So, there you have it! All the ways that sleep can affect muscle growth.

If you're spending a lot of time in the gym but you aren't seeing much progress, it could be that you aren't getting enough sleep. Prioritising your sleep is not only important for muscle growth but also for your overall health. The value of a good night's sleep should never be underestimated.

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