Chances are, you’ve already come across a lot of conversation about cortisol, the so-called stress hormone. In fact, preventing high cortisol is one of the biggest wellness trends of 2025. But have you heard of the cortisol circadian rhythm?

As Dr Isabel Viña Bas explains in her book Get Your Hormones Working, it’s actually a necessary hormone. She puts it pretty bluntly: without it, “a person cannot survive more than 24 hours, they die.” So, while the conversation about how to keep cortisol from rising too high makes perfect sense (it is, after all, another way to try to reduce stress), perhaps what we should really be talking about is the circadian rhythm of cortisol. Because our cortisol levels shouldn’t always be low.

Viña introduces this concept in her book. It refers not only to having adequate levels of the hormone, but also to encouraging a few specific peaks it should have throughout the day: “The highest occurs around 8 a.m., another milder one around 11 a.m. and a final small peak around 4 p.m.. After the latter, the levels progressively drop to their lowest point, around 10 pm, which facilitates sleep and the secretion of melatonin,” says the expert in her book, endorsing the importance of maintaining this stable cycle for correct hormonal and energy regulation.

There are certain circumstances that deregulate this rhythm. For example, when there is chronic stress. Instead of these peaks, there is a constant level of cortisol throughout the day that causes various consequences related to both its excess (abdominal fat for example), as well as by default (fatigue and apathy).

Other doctors have also spoken about these cortisol peaks, which are necessary for sufficient and constant energy. Having higher cortisol at 8 in the morning is necessary to be able to function. Specifically, Amy Shah during her interview on the podcast Lipstick on the Rim. She explained that during perimenopause, cortisol levels are higher and you experience and a greater sensitivity to the hormone. And precisely because of this, waking up in the middle of the night is almost always related (in 9 out of 10 cases) to the high cortisol levels – especially when it happens between one and four o’clock in the morning.

In addition to these circumstances, there are several daily habits that might be altering your cortisol circadian rhythm.

1. Not taking enough vitamin C

We often talk about the relationship between magnesium and B vitamins with the nervous system and, therefore, with cortisol. But, as Viña explains in her book, to restore the natural cortisol rhythm, it is important to boost vitamin C. Why? It is key to facilitate metabolism and the elimination of cortisol if there is an excess. Try increasing your intake of red fruits, kiwis, papaya, red bell pepper watermelon, tomatoes, orange and broccoli.

2. Consuming coffee after noon

This is one of the recommendations of Dr Shah and wellness expert Andrea Klimowitz. “Caffeine can be active in your body eight hours later. [Your] innocent 4 p.m. cup may be to blame for your insomnia,” said Kimowitz.

3. Not doing physical exercise you actually enjoy

Not everyone likes to work out – in fact, many of us see it as an unhappy obligation. Dr Viña claims we should be doing physical exercise that is actually enjoyable in order to connect with the body and encourage the release of endorphins. “It is important to avoid extreme or excess exercise because it can have the opposite effect and increase cortisol,” she adds.

4. Not drinking enough water

According to Dr Amy Shah, “When you consume seven to eight glasses of water every day, your body works well by helping you digest better, flushing out toxins. But when you are dehydrated, it interprets it as a stress trigger and increases cortisol levels.” So if you feel your levels rising, the expert advises drinking a glass of water to calm down.

5. Having normalised stress (and not identifying the cause)

We have made stress our life companion – we have normalised it. But when it comes to optimising the normal cortisol rhythm, it’s important to identify the sources of stress in our daily lives. That’s why Viña advises observing your reactions, reflecting on them and writing them down. “Writing helps to distance ourselves and gives us perspective on the situation. This exercise can help you identify patterns and thoughts that contribute to stress,” she concludes.

A version of this article originally appeared on Vogue Spain.