The physiology of recovery

Thursday, October 06, 2016. Author Pleuni Hooijman

In the first blog of this science series, we discussed the physiology of movement. This blog follows on to explain the processes of recovery that come into play after exercising.

The importance of recovery is often underestimated. This is quite surprising since the results you get from training are mainly determined by how well you allow your body to recover, and not from the training itself. Appropriate recovery from exercise allows you to train at higher volumes and intensities, and prevents injury and overtraining. What is recovery, and how are your genes involved in that?

What is recovery?

Although things like lowering your heart rate, breathing frequency and body temperature are clear signs of short-term recovery, there are many invisible, and slightly slower processes taking place within the body post-exercise. These include replenishing energy stores, repairing muscle damage, removing metabolic waste products, and restoring pH levels. Many immunological and hormonal responses which are key for recovery are impacted by your genetics.

Immunological responses

You may recognise the term immunological response from medical conditions like infections, but it is also part of a healthy response to physical stressors such as exercise.Interleukins are the important molecules for this response and facilitate communication between cells as well as playing a role in regulating growth.

IL-6 is an important interleukin that is produced in large amounts in both muscles and fat tissues in response to activity. It facilitates muscle repair, hypertrophy and is thought to be involved in glucose and fat metabolism. Your individual IL-6 genotype relates to the expression of IL-6 in your body. Those having the CC genotype have the lowest, CG an intermediate and GG the highest level of IL-6. The frequency of the G allele is higher within power athletes, which may be explained through its protective role against muscle damage following powerful muscle contractions.

Hormonal responses

Exercise also induces hormonal responses to aid recovery. Hormones are small molecules that control cellular function, such as energy metabolism, growth and protein synthesis versus breakdown. Important hormones that FitnessGenes tests for and that are related to exercise and recovery are testosterone, insulin and insulin like growth factor.

Testosterone regulates muscle mass by stimulating protein synthesis (anabolism) and preventing break down (catabolism). The concentrations of this androgenic-anabolic hormone fluctuate naturally throughout the day, but also in response to exercise (moderate amounts of exercise affect it positively, while exercising excessively affects it negatively). Your body fat, fitness level, age and genes together affect your testosterone levels. FitnessGenes uses the ESR1, SHBG1, SHBG2, and ACTN3 genotype to determine your genetic testosterone score.

Insulin has an anti-catabolic effect by increasing the rate of uptake of some amino acids while increasing protein synthesis and decreasing protein break down. It also replenishes energy sources by facilitating the transport of sugar into muscle and the subsequent synthesis and storage of glycogen (which is your body’s primary fuel source during exercise). Having a good insulin function improves recovery. FitnessGenes tests for your genetic insulin score, which can be found in the Action Blueprint under Nutrition Strategies.

Insulin like growth factor (IGF1)      
IGF1 supports the function of human growth hormone to repair proteins that are damaged during exercise, therefore impacting muscle growth. FitnessGenes tests for two variations of the IGF1 gene (IGF1 and IGF1_2) that code for the same protein, but have a slightly different effect on the protein’s function. The less common IGF1 A allele and IGF1_2 C allele are associated with higher circulating levels of IGF1 and with improved performance and increased strength.

Improve your recovery

One of the best ways to ensure that you recover quickly and completely is to do your exercise at the right time of the day for your body and to ensure that your macronutrient profile is optimising your fuelling and recovery. All of these questions are answered in your FitnessGenes DNA test and Action Blueprint.

Of course, it is key to listen to your body during and after exercise. If you feel you haven’t recovered properly, consider skipping or shortening your next training, or do it at a lower intensity. A varied and healthy diet and good hydration are essential for recovery, and sport massages and foam rolling can help to improve it as well. Take enough time for rest and a cool down after training, and pay attention to your sleep .

Want to know how your individual testosterone levels, insulin function, and IGF1 result is affecting your recovery? Unlock your unique fitness DNA with the FitnessGenes DNA Analysis Test or Genetic Workout System.


Huuskonen, A., Tanskanen, M., Lappalainen, J., Oksala, N., Kyröläinen, H. and Atalay, M., 2009. A common variation in the promoter region of interleukin­6 gene shows association with exercise performance. Journal of sports science & medicine, 8(2), p.271.

Buxens, A., Ruiz, J.R., Arteta, D., Artieda, M., Santiago, C., González‐Freire, M., Martínez, A., Tejedor, D., Lao, J.I., Gómez‐Gallego, F. and Lucia, A., 2011. Can we predict top‐level sports performance in power vs endurance events? A genetic approach. Scandinavian journal of medicine & science in sports, 21(4), pp.570­579.

Eider, J., Cieszczyk, P., Leońska­Duniec, A., Maciejewska, A., Sawczuk, M., Ficek, K. and Kotarska, K., 2013. Association of the 174 G/C polymorphism of the IL-6 gene in Polish power-­orientated athletes. The Journal of sports medicine and physical fitness, 53(1), pp.88­92.

​​Ben-­Zaken, S., Meckel, Y., Nemet, D. and Eliakim, A., 2013. Can IGF­I polymorphism affect power and endurance athletic performance? Growth Hormone & IGF Research, 23(5), pp.175­178.

Huuskonen, A., Lappalainen, J., Oksala, N., Santtila, M., Häkkinen, K., Kyröläinen and Atalay, M. 2011. Common genetic variation in the IGF1 associates with maximal force output. Medicine and science in sports and exercise, 43(12), pp.2368­2374.

Deal, C., Ma, J., Wilkin, F., Paquette, J., Rozen, F., Ge, B., Hudson, T., Stampfer, M. and Pollak, M., 2001. Novel Promoter Polymorphism in Insulin­Like Growth Factor­Binding Protein­3: Correlation with Serum Levels and Interaction with Known Regulators 1. The Journal of Clinical Endocrinology & Metabolism, 86(3), pp.1274­1280.

Ohlsson, C. et al. Genetic determinants of serum testosterone concentrations in men. PLoS Genet 7, e1002313, doi:10.1371/journal.pgen.1002313 (2011).

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