How Evening Sauna Use May Support Sleep
The Omega-3 Supplementation Guide
A blueprint for choosing the right fish oil supplement — filled with specific recommendations, guidelines for interpreting testing data, and dosage protocols.
You'll also receive updates from Rhonda & FoundMyFitness
In this member Q&A clip, Dr. Rhonda Patrick explains how evening heat exposure can fit into a sleep routine. Sauna raises core and skin temperature, then the cooling period that follows may help prepare the body for sleep. She recommends leaving enough time after heat exposure for body temperature to fall before going to bed.
Dr. Patrick also describes the acute hormone response to sauna. Small physiology studies found dose-dependent increases in growth hormone and prolactin with intense heat protocols. These responses were short-lived and depended on temperature, duration, humidity, and repetition. [1] [2]
Her practical approach is moderate and timing-focused. Dr. Patrick often uses a sauna or hot tub about two hours before bed and allows cooling to happen naturally, while her husband sometimes uses a cool shower. She distinguishes this routine from extreme research protocols and warns that entering bed while still overheated can disturb sleep.
- ^ Kukkonen-Harjula K; Oja P; Laustiola K; Vuori I; Jolkkonen J; Siitonen S, et al. (1989). Haemodynamic and hormonal responses to heat exposure in a Finnish sauna bath. Eur J Appl Physiol Occup Physiol 58, 5.
- ^ 3788622
So the effects of heat and exercise. Let's talk about some very interesting effects that we've definitely discussed in the past. Growth hormone and prolactin are— they're 2 key hormones that are important in the regulation of slow-wave activity. Regular sauna use is probably one of the most powerful stimuli that increases both growth hormone and prolactin. So growth hormone, the effects of sauna use on growth hormone levels really depend on many factors, including duration, temperature, and frequency. So for instance, two 20-minute sauna sessions at 80 degrees Celsius with 30 minutes of cooling period in between can double growth hormone levels basically from their baseline.
On the other hand, two 15-minute sauna sessions at about 100 degrees Celsius dry heat separated by a 30-minute cooling period can cause a 5-fold increase in growth hormone levels. So there's also a really remarkable effect when you do sort of repeated sauna use. So repeated sauna use, for example, you do one— you do two one-hour sauna sessions at 80 degrees Celsius. This is very, very high for 7 days in a row. That leads to a 16-fold increase in growth hormone levels in men. That's not something It's just— it's kind of just as a proof of principle example of how there is a dose-dependent effect of heat stress on growth hormone. And that's something, again, that is temperature and duration dependent. I don't necessarily think it's good to do that much heat stress. That's pretty intense.
But I just wanted to highlight the effect that sauna use does have on growth hormone levels. The heightened growth hormone levels typically last a few, I would say more like a couple hours after sauna use. They released after about 2 hours, they start to go down close to baseline levels. It's also kind of interesting that combining exercise with heat stress or sauna use may also increase growth hormone levels even further than when you just use, for example, sauna alone. And mostly it probably has to do with, again, your elevations in core body temperature are going even higher than one alone, right? So let's talk about prolactin. Prolactin in one study, men that used the sauna, they were in the sauna for an 80-degree Celsius sauna until they felt exhausted.
They had a tenfold increase in prolactin levels. In another study, women who did a 20-minute dry sauna twice a week had a 510% increase in prolactin levels after each sauna session. And similar to growth hormone, prolactin levels lasted for a couple of hours. There are some other lifestyle factors in addition to sauna use, potentially even hot baths. Again, something that is going to elevate core body temperature. Exercise is one. So exercise can also increase both growth hormone and prolactin. I don't know the exact quantitative numbers and how much, but they also do increase it. And then sexual activity is another one that also increases both prolactin. So, you know, the effects of growth hormone and prolactin also, again, affect slow-wave deep sleep.
And so the idea is that, you know, doing doing these activities a couple of hours. So you want to make sure you're not doing it again right before bed because you want to allow your body time to cool down. And if you get in the sauna literally like right before bed, you might still be really hot and you won't cool down unless you then perhaps get into a cold plunge or do a cold shower to cool down. But doing it like, you know, a couple of hours before bedtime seems, seems like a good time. It's typically when I do my hot tubs. I do a lot of hot tubs in the evening, and I do them a couple of hours before I, I go to bed. So, um, that's all, I think, super interesting stuff that we haven't talked about before.
Heating activates warm-sensitive neurons in the hypothalamus that promote slow-wave activity in response to increased core body temperature and skin temperature. Yet again, another potential mechanism behind why sauna use, why hot baths, and even exercise, which elevates core body temperature, may promote slow-wave deep sleep. And then exercise combined with body cooling and warm baths combined, you know, with body cooling also, you know, may help, again, to promote slow-wave activity in deep sleep. Adriana is asking if I'm saying that sauna before bed can be helpful. So I do think doing sauna in the evening time is— can improve, improve sleep and including deep sleep. And for the reasons I mentioned, there were many reasons I mentioned.
But again, you want to make sure you give yourself enough time for your body temperature to cool down after doing that sauna, right? For me, that is typical. I typically get in either a hot tub or a sauna around 7:30 in the evening. So I put my son to bed at 7, and then 7:30 is time for my husband and I. And we typically then will either do a hot tub or a sauna around 7:30. And my natural bedtime is about 9:30. So I go to bed around 9:30. So I typically do mine two hours before I go to bed. My husband as well. He takes a little bit longer to cool down, which is why he'll take a cooler shower typically. I don't need to. I cool down pretty— my cool-down time is not as long as his. So 2 hours for me is quite nice. So making sure you're not doing it, again, right before bed is important because it can have the opposite effect where it disturbs your sleep, particularly because you were not able to cool down right before going to bed, and that is also very important.
Supporting our work
If you enjoy the fruits of
, you can participate in helping us to keep improving it. Creating a premium subscription does just that! Plus, we throw in occasional member perks and, more importantly, churn out the best possible content without concerning ourselves with the wishes of any dark overlords.
Sauna News
- A single Finnish sauna session temporarily increased circulating white blood cells.
- Hot water immersion more than doubles core body temperature rise compared to traditional saunas, potentially boosting vasodilation, cardiac output, and immune activity.
- Regular infrared sauna use increases blood vessel density in aged muscles by 33%, though muscle size, strength, and protein synthesis remain unchanged.
- Post-exercise hot tubs and saunas show minimal, inconsistent benefits in exercise performance enhancement, despite potential physiological effects.
- Post-exercise infrared sauna use contributes to a 25% increase in jump height and a 6.8% peak power boost in female athletes—a potential tool for enhancing power production.
