Cortisol is a stress hormone which is created in the adrenal glands (just above your kidneys) when you experience high levels of physical and/or emotional stress.
Some cortisol can be good for you
Because cortisol releases energy (in the form of blood glucose from your liver) to deal with a stressful situation, if it’s infrequent and brief it can really help you deal with a situation of emotional or physical stress. It should help you to feel alert and motivated. Cortisol levels should then return to normal. For example, raised cortisol followed by physical activity (such as running away from danger back in caveman days!) means you can burn off the raised glucose in the blood.
But you can have too much of a good thing
When stress is not followed by a burst of physical activity to wear off your cortisol (i.e. it’s just day to day stress), your blood sugars remain high and insulin release is triggered. Excess insulin resistance is a major driver of obesity and abdominal fat, as it prohibits fat breakdown.
And to make things worse, plummeting blood sugars also trigger cortisol release. So the tip is don’t skip too many meals – keep your blood sugars constant!. Raised cortisol can also affect thyroid hormone production, which can affect our metabolism in a bad way.
When ongoing stress turns to adrenal fatigue
Prolonged periods of stress (internal or external) will result in ongoing elevated cortisol and exhaustion. This leaves you feeling foggy and tired instead. Ongoing cortisol release (high levels over all 24 hours) leads to muscle breakdown, immune issues, gut issues, and insulin production issues, resulting in gastritis, irritable bowel syndrome, hypertension, asthma, migraines, anxiety, or depression.
If the prolonged period continues for a long time they become overloaded and stop producing correct levels of cortisol and instead produce adrenaline, This can cause us to feel irritable, shaky, lightheaded, and anxious. This is called adrenal fatigue which over time can lead to pure exhaustion.
Exercising the right way to reduce cortisol
Cortisol levels are high first thing in the morning (between 7am-9am) and should diminish throughout the day, falling to their lowest in the evening when you sleep. We want our cortisol levels to rise and drop throughout each day, mirroring normal sunlight levels.
Exercise can raise your cortisol levels, if it’s intense or long in duration. So keep any exercise that ticks this box to the morning when cortisol levels are naturally supposed to be high. It won’t raise cortisol levels any higher.
However when cortisol levels are supposed to be lower (in the early evening, as the sun is going down and especially before bed) you should stick to low impact, low intensity, relaxing exercise. Such as a nice slow long walk or some yoga or stretching. It’s not the time for interval training! If cortisol levels are high at night you might find it difficult to sleep or stay asleep.
The sleep and cortisol connection.
When cortisol is raised during the day, the body can’t produce the right amounts of melatonin. This is our sleep hormone which is essential for us to get good quality shut eye. If we don’t sleep properly, it increases our cortisol levels the next day and can also mess with our hunger hormones, increasing feelings of hunger and cravings and reducing feelings of fullness
Ensure you get 7-9 hours of sleep per night to decrease your stress levels and cortisol levels in your body. Engaging in stress releasing exercises such as meditation and yoga can really help before sleep.
How food can help lower cortisol levels
Foods with a high glycemic index can cause cortisol hormones to rise. These include foods and drinks high in sugar and starches. Think fruit juices, soft drinks, processed foods, foods with added sugars. These are best avoided or if you must, eaten in the morning when cortisol levels are naturally high.
But better still, stick to low GI foods for slow release energy and more stable cortisol levels. Oats, wholegrains, vegetables and fruit, as close to nature as possible. This includes protein such as eggs, meats, poultry, fish. Combining animal proteins with carbohydrates which contain more natural sugars, can help to keep the cortisol release in check.
If you exercise a lot, eating protein and carbohydrates after exercise can help to offset the increased cortisol that a heavy training session can produce.