This is how swimming twice a week affected my sleep

Ever since I grew up across the street from my hometown pool, I’ve loved swimming and being in the water. Whether it was a pool, lake, or ocean, I spent most summers in the water with friends, which led to taking swimming lessons, becoming a swim instructor, working as a lifeguard, and becoming a competitive swimmer.

It turns out that this enjoyment of water is also backed by science. You may have heard of a “blue recipe“or the Theory of the blue mind, popularized by marine biologist Wallace Nichols. These theories suggest that there are intrinsic beneficial connections between people and water. Being near water or “blue space“It has been proven to increase dopamine, serotonin and oxytocin levels in the brain and decrease cortisol levels, which lowers heart rate and stress levels.

First thoughts and expectations

For this experiment, I wanted to investigate the impact of swimming and being near water on my sleep quality. Unfortunately, I don’t live near an easily accessible natural body of water like a lake or ocean. However, I do live near an indoor pool, where I decided to swim laps.

I dove headfirst into this research, assuming that I would sleep better on days that I swam for a few reasons. Not only does being around water have a naturally calming and meditative effect, but swimming is also a excellent form of exercise and has many known benefits, including better sleep.

I spoke to a licensed psychotherapist and sleep specialist Annie Millerwho explained that movement and exercise increase the body’s natural drive to sleep, making us feel sleepier and having a better quality of sleep overall. Swimming is no exception.

“Swimming is an activity that promotes deeper, more conscious breathing, which encourages relaxation. Deep breathing can have a positive impact on sleep quality,” says Annie.

Let’s be clear: I’m no scientist, but I did my best to keep other variables the same. I limited my coffee consumption to two cups in the morning and kept my diet the same every day, including what and when I ate. I didn’t drink alcohol and took the same sleep gummies every night. I also didn’t do any other strenuous exercise on the days I didn’t swim.

I swam a consistent 1 mile each swim day. The only difference was the speed at which I completed the mile, which varied from 38 to 40 minutes. I tracked my workouts and sleep data with my Apple Watch, waiting until the end of the trials to compare and contrast the information to avoid prematurely skewing the results. However, I immediately noticed that my sleep quality seemed worse on the nights after swimming compared to days when I didn’t swim.

Swimming vs. Sleep Data

The results

The final results of this experiment shocked me: on average, I slept less and was awake more on days I swam than on days I didn’t. This was the exact opposite of what I expected.

Sleep on swim days versus non-swim days

I also noticed an interesting pattern in my sleep when I compared swim days to the rest days immediately following a swim day, or what I’ll call a “recovery day.” On swim days, my total sleep time averaged just under 7 hours, and my awake time was about an hour per night. On recovery days, my total sleep time was much higher — around 8.5 hours, with a significantly lower awake time of about 30 minutes.

Sleeping on swim days versus recovery days

To be honest I was baffled. I read online to see if others had a similar experience and found the likely cause. According to writer and competitive swimmer Olivier Poirier-LeroyThe more intense the workout, the harder it can be to sleep due to spikes in cortisol and norepinephrine (adrenaline) levels. It can even take up to 48 hours for norepinephrine levels to return to normal after a high-intensity workout — which seemed to be the case for me.

The fact that I consistently left the swim center with wobbly pool noodle legs was probably a sign that I was pushing myself a little too hard. Despite not getting the results I expected (or hoped for), I did notice a few other interesting changes during this experiment that are harder to quantify, but worth mentioning.

My stress disappeared

My lap swimming sessions were in the middle of my work day, around 1pm. Every time I left for the swim centre I felt lethargic and stressed about going, while I had other tasks to complete. Some days I even had an accompanying tension headache before swimming and generally did not look forward to training.

During the training, those negative feelings slowly washed away. I started looking forward to reaching that meditative state where I could just focus on my breathing and calm my mind.

After each swim I noticed a significant improvement in my mood. I was less stressed and didn’t suffer from that typical afternoon slump where I would normally opt for another cup of coffee to get through the rest of the day. I felt physically tired, but mentally energetic and focusedready to tackle the rest of the to-do list for the day.

Conclusion and closing thoughts

I believe being in and around water has a positive calming effect, as the Blue Mind Theory suggests, but perhaps not enough to offset the negative effects. Rising cortisol levels I suffered from pushing myself too hard.

As Finding Nemo’s Dory says, I’ll “just keep swimming” using the insights I’ve gained from this experiment until I find a middle ground that improves my sleep quality. I hope to conduct similar studies with less intense workouts or just spend time near water every day to further explore these theories.

If you’re like me and looking for ways to sleep better, don’t miss our simple tips and tricks, like limiting your technology use, developing a bedtime routine, journaling or meditating, and—trust me—making sure you’re exercising at the right intensity and time of day.