I will discuss what my data shows, how easy or difficult I found this strategy to implement, and what previous research says. These three factors will be combined for an overall score and grade on how effective saunas, steam rooms and hot baths can be for improving sleep.
HOW COULD HEAT OR WATER IMPROVE SLEEP QUALITY?
Saunas, steam rooms, hot baths and spas or jacuzzis are used in almost every culture around the world. Which method people use the most varies, but they are often seen as a positive activity for health. This may be the cleansing nature of the task, the relaxation they provide, or even the social or spiritual elements.
I’m not sure if there has been many studies looking directly into the positive benefits these activities can have on sleep, but I do know of a number of clients I see who have a warm bath to unwind and relax at the end of a tough day, in the hope that it may lead to a better night’s sleep for them. I wonder if it will do the same for me.
I am pretty lucky to live in an apartment complex with a steam room, sauna and spa bath or jacuzzi as part of our facilities. This made it pretty easy to test if these activities could assist my sleep.
For the first four nights, I used the steam room for 30-minutes between 9:00 and 9:30pm.
For the middle five nights, I used the sauna for 30-minutes between 9:00 and 9:30pm.
For the last five nights, I used the hot spa with jets for 30-minutes between 9:00 and 9:30pm
Let’s see which intervention had the most positive impact on my sleep…
Comparison: Steam room vs Sauna vs Spa
Based on my sleep diary data, the findings were as follows:
- The number of awakenings:
- Sauna – 0.2 per night
- Spa – 0.4 per night
- Steam room – 1.75 per night
- less is better
- Time in bed:
- Steam room – 7 hours 47 minutes
- Spa – 7 hours 15 minutes
- Sauna – 7 hours 0 minutes
- 8 hours is ideal for me
- Time to bed:
- Sauna – 11:14 pm
- Spa – 10:53 pm
- Steam room – 10:15 pm
- 11:30pm is ideal for me
- Total sleep time:
- Steam room – 7 hours 16 minutes
- Spa – 6 hours 57 minutes
- Sauna – 6 hours 44 minutes
- 7 hours 30 minutes is ideal for me
- Sleep onset latency:
- Steam room – 10 minutes
- Spa – 13 minutes
- Sauna – 14 minutes
- quicker is better
- Wake after sleep onset:
- Sauna – 2 minutes
- Spa – 5 minutes
- Steam room – 21.75 minutes
- less is better
- Rise time:
- Sauna – 6:19 am
- Spa – 6:08 am
- Steam room – 6:03 am
- 7:30am is ideal for me
- Sleep quality:
- Sauna – 5/5
- Spa – 4.6/5
- Steam room – 4.25/5
- more is better
- Sleep efficiency:
- Sauna – 96.14%
- Spa – 95.86%
- Steam room – 93.31%
- higher is better
AND THE WINNER IS…
The sauna won 6 categories, and the steam room won 3. Interestingly, the spa with jets did not win any category, but it also wasn’t the worst in any category either.
The sleep quality of 5/5 after the sauna was the best it had been for the entire year, which was quite surprising. I barely woke up at all but didn’t get as much sleep as I did in the other conditions.
IS HAVING A SAUNA OR STEAM OR HOT BATH A GOOD SLEEP STRATEGY?
IS IT EFFECTIVE?
Yes. With only a half an hour of time in the sauna, steam room or spa about 60-90 minutes before bed, I fell asleep early and quickly and slept well throughout the night. For me, I’d be happy to keep doing any of the three strategies when I felt like it as an excellent way to relax, tune into my body and be mindful in the evening, with the sauna being the most effective. Doing it too closely to bed may not be as helpful as it can take a while to cool down, but the drop in body temperature can also bring on sleepiness and result in faster sleep onset.
I, therefore, give the effectiveness of this strategy a 22/25.
CAN IT BE APPLIED?
This would depend on accessibility. For me, it was easy to apply as I had all three options in my apartment complex. Going to a sauna or steam room could become expensive if you had to pay for it every time, however, and may not be accessible either. If people have a hot bath at home, that could be just as good. A hot shower would be available to most people, but I am not sure if that is as effective.
I, therefore, give the applicability of this strategy a 16/25.
IS IT SCIENTIFIC?
A 1985 study by Bunnell and Horvath woke up 10 participants during the middle of their sleep and put them in hot water for 30-minutes before allowing them to go back to sleep. Their core body temperature returned back to normal within 60-minutes. Interestingly, their REM sleep or time taken to get back to sleep was no different than the group that was woken without the hot water immersion. They did have a deeper sleep in their subsequent sleep, especially the second cycle of sleep once they fell back to sleep (Bunnell & Horvath, 1985).
A follow-up study published in 1988 compared people who immersed themselves in hot water (41 degrees) for an hour in the morning, afternoon, early evening, and late evening (Bunnell, Agnew, Horvath, Jopson & Wills, 1988). They found that late evening immersion, which finished just before bedtime resulted in more deep sleep in the first sleep cycle that night. The early evening exposure had a quicker sleep onset time and more deep sleep in the second to fourth sleep cycles that night (Bunnell, Agnew, Horvath, Jopson & Wills, 1988).
A 2018 systematic review by Hussain and Cohen looked at 40 studies on the benefits of dry sauna bathing, including 13 randomised control trials. The majority of the studies reported beneficial health effects, with limited data suggesting a positive impact on sleep.
I, therefore, give the science of this strategy a 30/50.
Overall, using a sauna, steam room or hot bath before bed as a way to wind down and sleep better gets a score of 22/25 + 16/25 + 30/50 =
WHAT I RECOMMEND
If you have a bathtub at home, having a 30-minute to 60-minute bath in the early evening or late evening is likely to help you get more deep sleep that night. It could assist in reducing your arousal levels or by producing a drop in your body temperature before sleep. Saunas, spas or steam rooms are what I experimented with and found them all helpful, but there isn’t a heap of evidence suggesting that they are useful for sleep.
Like all of my recommendations, try the technique out for yourself if you think it would help, see if it does work for you, and then if it is easy to build into your regular daily routine, see if it can become a helpful habit for you over time. Don’t try to change everything at once. Start with one thing, see if it works, and then move onto the next thing if it does not.
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