Dr. Andrew Huberman recently addressed widespread misinformation about women and cold plunges during his appearance on the Modern Wisdom podcast with Chris Williamson. His comments directly challenge claims circulating online that women should avoid cold water immersion due to cortisol concerns.
Huberman was unequivocal in his position: “You could jump in a 40 degree Fahrenheit cold plunge, doesn’t actually increase your cortisol. All this nonsense going around the internet about, you know, women shouldn’t do a cold plunge and if they do, not as cold. Okay, maybe, but it’s always attributed to increases in cortisol. Cold plunge reduces your cortisol levels.”
He emphasized this isn’t speculation but established science: “You can look at the data. The data show that it goes down. Adrenaline goes up. Dopamine goes up. Norepinephrine go up.”
Much of the confusion stems from fundamental misunderstandings about cortisol itself. Williamson asks Huberman: “Most people think about cortisol as a bad thing that you want less of. Is that the right way to think about it?”
Huberman answered by saying that cortisol has been unfairly demonized: Not at all.”
He described cortisol’s actual purpose: “Cortisol’s job is to deploy energy sources for your brain and body to be able to react to things, think and move. So cortisol naturally goes up a bit during stress and it comes back again provided you don’t ruminate on that stress too much.”
Huberman detailed how healthy cortisol function works throughout the day. The most important revelation concerns what happens when we wake up: “The reason you wake up every single morning even if you have an alarm clock is because of something called the cortisol awakening response.”
He outlined the natural 24-hour cortisol pattern: “A couple hours before sleep, your cortisol is low. Your heart rate’s low. You’re calm. You go to sleep. Your cortisol is then at its absolute lowest levels for the entire 24 hours. And by the way, this is the same time when melatonin, the sleepy hormone, is at its highest levels.”
He continued: “After about four or five hours of sleep…. your cortisol is starting to rise. At some point, maybe 6:00 a.m., maybe 8:00 a.m….. you wake up. You wake up because the cortisol level reached a certain threshold.”
This morning cortisol elevation isn’t just normal, it’s essential. Huberman noted that viewing bright light in the first hour after waking “can increase your morning cortisol spike by up to 50 percent.”
The morning cortisol increase serves a critical function: “This is nature’s evolutionarily hardwired mechanism for giving you the opportunity to boost your cortisol so that you have energy to lean into the activities of your day.”
More importantly, this morning spike protects against afternoon and evening stress: “Spiking your cortisol in that first hour after waking is so important because that negative feedback loop mechanism kicks in about 3 hours after you’ve been awake…. If you don’t spike your morning cortisol, what ends up happening is your cortisol system… is primed for stress events to give you big lasting increases in cortisol later, which make it hard to fall asleep, which make it hard to stay asleep.”
Huberman made clear this cortisol pattern applies universally: “This is the healthy cortisol curve for men, women, kids, pregnant women, post-menopausal women.”
He acknowledged post-menopausal women may need additional support: “It tends to flatten out a bit and they need to do additional things to get that spike earlier.”
When asked about timing stress, Huberman explained that even intense evening exercise creates temporary cortisol elevation without problems: “If you were to do say a very intense workout in the late afternoon, evening, it’s been demonstrated that will triple or quadruple your baseline cortisol levels for a few hours, not a problem. You can take a hot shower afterwards, do some slow breathing and calm down… you could probably fall asleep just fine.”
The key distinction is that cold plunges operate through different mechanisms than commonly assumed. While they do create a stress response, that response manifests through adrenaline and dopamine increases rather than cortisol elevation.
Huberman’s message is straightforward: recommendations against cold plunges for women based on cortisol concerns are scientifically unfounded. The data clearly shows cold water immersion decreases rather than increases cortisol levels, making the entire premise of the warning incorrect.
