We have discussed Cortisol- our stress hormone in our earlier blog. We are going to discuss how we can optimise our cortisol for exercise & recovery.
When we are exposed to physical( exercise, injury) or physiological stress( stressful events), our body releases cortisol as part of our stress response. During this stress response, cortisol regulates glucose metabolism & blood pressure & reduces metabolism. Like testosterone & estrogen, cortisol is a steroid hormone. It is derived from cholesterol & responds to steroid receptors within our cells.
We can further classify cortisol as glucocorticoid hormones. These are types of steroid hormones that enter inside cells & bind to glucocorticoid receptors. This causes various genes to be switched on or off. Cortisol switches on manufacturing of anti-inflammatory proteins & switches off production of proinflammatory proteins.
During stress, we have to make sure that our brain, tissues & muscles have adequate supply of glucose for energy. Our stress hormone stimulates production of glucose by the liver, thereby increasing the blood glucose levels & maintaining energy supply for tissues.
Cortisol stimulates a process known as glucogenosis- production of glucose in the liver from breakdown products of protein & fat. When cortisol is released, it breaks down protein in muscle. This results in release of amino acids which are then converted into glucose by the liver. The newly produced glucose is released in the bloodstream which are then supplied to various tissues
Cortisol also acts on fat stores in fat tissue & breaks down triglycerides into fatty acids & glycerol. These fat metabolites are converted into glucose by the liver & are then released into the bloodstream. Besides, Cortisol also acts on Pancreas to inhibit secretion of insulin, thereby making blood sugar levels high.
As a short term stress response, Cortisol suppresses the immune system to fight against inflammation. This is important since it stops our body from spending too much energy in fighting against excessive inflammation. When Cortisol binds to glucocorticoid receptor, receptor moves to nucleus & alters the way genes are made into proteins.
Cortisol also enhances the blood pressure. It may sensitize blood vessels to the effects of noradrenaline. It therefore stimulates reabsorption of sodium & water by kidneys which increases blood pressure & volume.
Adrenal glands, located just above the Kidneys, produce cortisol. Production of Cortisol is regulated by two key structures in the brain: hypothalamus & pituitary gland. This has been covered in length in our previous blogs & our E-book “KNOW YOUR BODY”.
When exposed to a stress response, your hypothalamus releases corticotropin-releasing hormone. This acts on the pituitary gland which secretes adrenocorticotropic hormone. This travel down the bloodstream to the adrenal where it stimulates production of cortisol. This communication network is called the HPA axis. The activity of this axis will influence how much cortisol you produce in response to stress events.
A healthy amount of cholesterol , found in liver & also consumed from various foods, is required for production of cortisol. Levels of cortisol in your blood varies throughout the day in line with your circadian rhythm. Cortisol levels are highest when we wake up in the morning & lowest during night time. This pattern of hormone release is called diurnal variation. The relationship between cortisol & time of the day also depends upon your internal biological clock. This is influenced by your genetic code.
How are cortisol & exercise related?
Understanding the relationship between cortisol & exercise is not that straightforward. Exercise is a short term stressor which increases circulatory level of cortisol. Post workout, cortisol level returns to normal. Adequate recovery between workout sessions is required to ensure the cortisol levels are not elevated over time. Inadequate recovery can lead to fatigue & reduced performance. Amount of cortisol released in response to workout depends upon intensity of workout, duration of exercise , experience & time of the day. The following is vital to note:
- More intense workout sessions & exercises above 60% of your VO2max level increases your cortisol levels. On the other hand workout below 40% of your VO2 max leads to minimal increases in cholesterol.
- Heavy weight/resistance training increases your cholesterol level.
- Long duration workouts in excess of 120 minutes can elevate your cholesterol levels.Endurance athletes with ,inadequate recovery between training sessions, are at high risk of elevated cortisol levels.
- Seasoned workout training folk experience low rise in cortisol levels as compared to trained individuals. This results from adaptation to the HPA axis in response to regular exercise. People who workout regularly are at lower risk of elevated cortisol levels.
- Cortisol levels follow a circadian rhythm & fluctuate over a 24 hour cycle. The time of the day you exercise influences cortisol levels. As shared in an earlier paragraph, cortisol levels are high during the morning when you wake up. Intense of long duration workout in the morning can lead to increased level of cortisol level.
Cortisol is beneficial as a part of short term response to physical or physiological stress. The problem starts when we have elevated cortisol levels for a longer period of time. This generally occurs when we undergo excessive physical training without sufficient recovery. Long-term exposure to cortisol can lead to breakdown of muscle tissue since it is a catabolic hormone. This can negatively impact your exercise performance. Cortisol increases your blood pressure level & prevents insulin secretion. Therefore elevated cortisol levels for a long period of time can attract diabetes. Since it suppresses your immune system, prolonged elevated cortisol level can make you more susceptible to infections. High/elevated cortisol levels can lead to Fatigue, low mood, insomnia, blood sugar abnormalities, high blood pressure, low bone mineral density & muscle weakness. On the flip side, relatively low cortisol levels can lead to muscle & joint pain, weight gain & fatigue.
Variations in genes encoding glucocorticoid receptors can impact function & quantity of these receptors which helps you determine your sensitivity to cortisol level. Your exposure to physical & physiological stress is linked to your lifestyle. Although it is difficult to control stress related to your workplace & home, you can obviously control stress through modifying factors such as diet, sleep & caffeine consumption.
Discover your personal traits & learn about your specific genetic predisposition to Cortisol sensitivity. By subscribing to our membership & personalised fitness programs, you will not only receive information about genetic response to nutrition & fitness but also be coached by an international fitness coach who will cover both genetics powered nutrition & exercise aspects of the program that will help you maximise your fitness potential & improve your mental health. Sign up for our membership here.
