We all feel the strain in our muscles the day after a major workout. Understanding our physiology during exercise is key to ensuring healthy muscle recovery post-workout. So what is actually happening to our muscles during exercise and recovery?
Exercise effects our bodies’ natural equilibrium, known as homeostasis, in several different ways. Many of these changes we can feel ourselves during a workout. For example, our breathing and heart rate both spike up during particularly taxing exercises. The circulatory system needs to compensate for the increase in metabolic activity in our muscles. It needs to transport more oxygen and nutrients, and quickly disposal of the carbon dioxide waste product, which it does by increasing our heart and breathing rate.
Exercise requires large amounts of energy, which the body provides to the muscles that need it most. Adenosine triphosphate (ATP) is the principal metabolite that provides energy for all our biology and allows our muscles to contract . It is produced by the mitochondria, microscopic powerhouses of the cell that convert glucose and oxygen into ATP through the process of aerobic respiration. Mitochondria are mostly concentrated in muscle cells, where they produce the ATP to power muscle contractions. Since ATP cannot be effectively stored in cells, it needs to be continually created according to supply and demand.
During exercise, respiration goes into hyperdrive to provide enough energy demanded by our muscles. If not enough oxygen is available, the body instead produces ATP from glycogen through an anaerobic process, with another byproduct being lactic acid. This leads to the distinct feeling of soreness that can course through our body during particularly gruelling exercise sessions. Digestion is also slowed as energy is directed to our muscles.
The effect of different types of exercise
Exercise, especially strength-based training, forces our muscles fibres to contract and stretch repeatedly. This causes tiny tears in the fabric of the muscle, the size of which depends on the intensity of the exercise. This causes the feeling of muscle soreness you might be familiar with the day after exercise. While these tears are normal and essential to the process of building muscle, over-training can lead to larger tears and injuries like muscle strains.
The type, duration and intensity of your chosen exercise can also influence the effect on your body. For example, endurance training like running or cycling makes your muscles stronger and less likely to wear out. It also has a range of holistic health benefits; it can enlarge your heart for better blood flow, increase lung capacity, improve metabolism and coordination. However, it is not the best choice of exercise if you are looking to grow your muscles for aesthetic purposes.
This is where strength training comes in, which increases muscle size through repetitive resistance exercises. You can do this using weights, resistance bands or simply against your own body weight. This forces your muscles to contract as hard as possible, increasing the contractile filaments within the muscle and making them appear larger.
Some forms of exercise like swimming involve a combination of the two types, as it improves endurance and involves resistance against the water .
Muscle recovery after exercise
As exercise stops and we enter the cool down period, our bodies gradually return to homeostasis and normal operation is resumed. Recovery time depends on the intensity, type and duration of exercise as well as your underlying physical fitness. Rest is as important as training itself, as this is where muscles are rebuilt and grow back bigger. Muscle recovery also gives your body a change to repair all the damage caused by exercise and clear lactic acid from your system.
During recovery, satellite cells repair the microscopic tears sustained during exercise. They replicate, mature and fuse to the damaged muscle fibres, forming a new muscle protein strand that increases the size and strength of the muscle to ensure it can keep up with future demand. Exercise therefore exposes your muscles to a form of stress known as eustress which may be painful in the short term, but will lead to greater long term gains. The rest period is when the body rebuilds muscle so that it is bigger and stronger than before.
Strategies to speed up muscle recovery
While muscle recovery is a natural process that the body does by itself over time, there are some helpful tricks to speed up the process so you can get back to training:
- Get more sleep: Sleep gives the heart a chance to rest, cells to grow and muscles to repair. Therefore your body will require a longer lie following exercise.
- Eating well: Eating a balanced diet is essential to health and longevity; it is also particularly important during muscle recovery. Protein can help rebuild muscle fibres, while carbohydrates restore depleted glycogen levels.
- Drinks: Exercise, especially during hot weather or in sweaty gyms, causes the body to lose a considerable amount of water through our breath and sweat. Dehydration can impair your muscles’ ability to repair themselves, so replenish with water and perhaps tart cherry juice, which has been linked to reduced muscle inflammation after workouts.
- Supplements: The health supplement scene has grown exponentially, with more people turning to taking supplements to boost muscle recovery. One such supplement is Timeline, which contains Mitopure’s purified urolithin A. This powerful postbiotic is produced by the gut after eating polyphenols contained in certain foods, especially pomegranate. Timeline cuts out this middle step and provides 500 mg of urolithin A, which boosts mitochondrial health and has been shown to improve muscle endurance in human clinical trials.