I tried swimming every day - here’s how it affected my fitness, sleep and mood after just one week

Swimming every day can improve fitness, muscle tone and mental health, as writer Kerry Law found out with this seven-day challenge

Kerry Law portrait next to image of swimming pool, representing the challenge to swim every day
(Image credit: Kerry Law)

Swimming is often named one of the best cardio exercises around. It burns calories, boosts heart health, strengthens muscles, and can improve your flexibility and mood - so is it beneficial to go swimming every day? I took on the challenge to find out.

According to Sport England, about 4.7 million people swim twice or more every month, making it the fifth most popular activity. But unless you're someone who trains for competitions like triathlons, you may view it as sitting on the more leisurely end of the exercise scale. Something you do on holiday or when you fancy a weekend splash at your local pool. But doing swimming as a workout can offer so much more than a bit of fun. 

I'm not a competition-level swimmer, but I'm OK. I used to swim regularly but the habit has fallen by the wayside a little as I've introduced other workouts into my life, such as running before work and strength training at the gym. My weeks are spent juggling work deadlines, caring for small children, struggling to get enough quality sleep, and dealing with plenty of “ladmin” (life admin) before I even contemplate scheduling a swim at my local pool - but I enjoy it. 

So instead of keeping swimming on the margins of my workout schedule, I decided to put it front and centre of my exercise plan for a week to see what would happen. Knowing all the many proven health benefits of swimming, would a daily dose of pool time improve my overall fitness? Would making it an evening swim help me sleep better and create a moment of calm at the end of a busy day? Here's what I learnt in just seven days. 

Benefits of swimming every day

1. Swimming can help you develop a toned body

“Swimming is a great way of improving muscular endurance and producing a lean, toned physique,” says Sam Quinn, a Level 3 personal trainer and personal training lead at Nuffield Health. “The four main strokes - freestyle, breaststroke, butterfly and backstroke – all require the whole body to be working simultaneously, using high energy outputs from the muscles whilst burning lots of calories.” 

I love a good stretch (the yoga mat is my happy place) so it felt good to reach long into each stroke, knowing this was boosting the impact of my swim. Whether front crawl, breaststroke or the occasional backstroke (I can’t even attempt butterfly), there wasn’t a stroke where I didn’t feel a stretch in the shoulders, biceps, core, glutes, hips and calves.

And because you’re supported by the water, you can shift the effort either into the lower body if you want to work your glutes and legs, or into your upper body if you need to strengthen your chest and arms (seasoned swimmers use kickboards and pull buoys to help here). As an alternative form of strength training, it's a great option.

Quinn adds that with swimming you can exercise at various intensities using interval training, swimming drills or steady-state swimming (my preference) so you can dial it up or down depending on the physical improvements you are aiming for.

On the evenings I swam after a morning of weights in the gym, it felt like a suitably complementary exercise - one that helped recovery and served as a satisfying reminder of which muscles were getting a good workout.

Sam Quinn, personal trainer at Nuffield
Sam Quinn

Sam Quinn is a qualified Level 3 personal trainer at Nuffield Health Devonshire and the personal training lead at Nuffield Health. He has over 10 years of one-on-one coaching experience and previously, she spent eight years working with the elite swimming programme for Plymouth Leander swim team, one of Britain's leading competitive swimming clubs, achieving Olympic Gold in the 2012 Olympics, World, European and Commonwealth Championship titles. 

2. Swimming can reduce stress and boost mood

Swimming is well-known for being good for our mental health. A poll by Swim England found that the sport had helped reduce the symptoms of anxiety or depression for 1.4 million adults in Britain, with many saying it made them feel happier and more motivated.

But what elevates it above your standard endorphin-boosting exercise, could be down to the watery environment itself. As reported by the BBC, there is a growing body of research suggesting that exposure to ‘blue space’ (pools, lakes, the sea) has a positive impact on our mental wellbeing. It seems that being in or near water increases levels of the happy hormones, dopamine, and oxytocin, and causes cortisol, the stress hormone, to drop. This creates a Zen-like calm that has been dubbed the ‘blue mind’ state.

‘Blue mind’, a term first coined by Dr Wallace J Nichols in his book of the same name, describes the mildly meditative state we can experience when swimming, floating, paddling or even simply gazing at the water. Scientists are unclear as to exactly why water has such a powerful effect on our psyche, but theories suggest it may be down to our own bodies being mostly water. We are synching, on a primal level, with our environment. One that, for our primitive ancestors, signalled a place in which to thrive.

It makes sense then that an immersive watery activity such as swimming could be activating my ‘blue mind’ so effectively. During every swim, I made sure to spend at least some of the time ignoring my technique or counting laps, and simply indulging in some moving meditation. Noticing how the water feels as I glide through it; how it sounds as I splash and blow out bubbles; how the light reflects off the tiles; and even how the chlorine smells and tastes. It’s a great mindful exercise for an evening.

3. Swimming may improve sleep quality

With its ultra-calming, ‘blue mind’ qualities, does it follow that swimming could also help you get a better night’s sleep? Inez Griffin, senior health and wellbeing physiologist with an MSc in Sport and Exercise Science who also works with Nuffield Health, says: “We know that daily exercise can help us sleep better, but it’s important to consider what time of day we’re exercising, and how vigorously.

“High-intensity exercise can cause increased adrenaline levels, heart rate, and body temperature which isn’t ideal right before bedtime. A light to moderate-intensity swim could be a good exercise choice in the evening, but you should consider how far and fast you swim, and which stroke you choose. Try a stroke which you find easier and swim at a comfortable pace in order to help keep it relaxing,” she suggests.

Throughout my ‘swim week’ I kept pace and intensity fairly slow and low as I was swimming beyond 9 pm. I stuck to an easy front crawl, mixing it up with slower laps in the breaststroke to avoid any spikes in heart rate and help dial down the cortisol. The ritual of the post-swim shower and changing into comfy loungewear suited the pre-bedtime routine. 

However, when it came to improving the quality of my sleep, my Fitbit (taken with a pinch of salt as even the best Fitbits and other trackers lack complete accuracy) told me my nightly swims didn't have any impact on the length or quality of my sleep. Longer periods of deep sleep still alluded me but my sleep quality wasn't any worse - perhaps I was offsetting any potential benefits by catching up on swim stats and social media much later in the night...oops. 

Inez Griffin, an expert who works with Nuffield Health
Inez Griffin

Inez Griffin is the senior health and wellbeing physiologist at Bournemouth Nuffield Health Hospital. She has worked in preventative healthcare for five years within both clinical and community settings, with her current role involving delivering health assessments and helping clients optimise their health. 

Inez is also an ex-national level swimmer who competed for over 10 years.

4. Swimming can help with weight loss

As with any aerobic activity, it’s no surprise that swimming is an effective calorie burner. How many calories swimming burns will differ for every person but Harvard Medical School estimates that during a 30-minute low-intensity swim a 57kg woman can burn around 180 calories, a number that rises with body weight as an 84kg woman could burn 266 calories in the same session. 

Switch it up to a vigorous 30-minute swim using, say, front crawl over breaststroke, and the same women could be burning around 300 and 444 calories respectively. It's not as intense as HIIT or running - which is where running wins in the swimming vs running debate - but it's decent. However, to lose weight you would still need to pair it with a calorie deficit over several weeks, something my week-long swim challenge didn't allow for. 

As I was swimming in the evenings and, therefore, keeping the intensity low, this meant my calorie burn was on the lower end of the scale. It still proved a much better replacement for what I would usually be doing around the same time - sitting on the sofa at home.

Adding aerobic exercise into my evenings (an often fairly inactive period), resulted in me hitting my calorie burn target every single day, according to my Fitbit. This surprised me as I usually hit it four or five days out of seven (due to rest days), and during ‘swim week’ I even skipped a couple of gym sessions to make time for the pool.

Kerry Law standing in the changing rooms after swimming every day for a week, next to image of a swimming pool

(Image credit: Kerry Law)

5. Swimming is good for your joints and your posture

The supportive nature of water means that swimming is the kind of exercise you can do on an active rest day or if you have an injury. Jonathan Kibble, Head of Exercise and Physical Activity at Vitality, says, “As swimming is low impact compared to, say, running it’s a great way to get your heart rate elevated and improve your fitness without putting too much pressure on your joints. This is great if you have any pre-existing injuries or just want a gentler workout.”

Thankfully, I wasn’t suffering from any injuries but I welcomed the opportunity to offset the hours spent working at my laptop. Kibble adds, “Swimming can be a great way to help alleviate any problems you may have surrounding your shoulders and neck. This is particularly relevant as many of us spend time hunched over our desks. Studies [by the likes of the University of Applied Sciences Wiener Neustadt] have shown that swimming regular lengths will strengthen your muscles, assisting you in standing straighter."

Jonathan Kibble
Jonathan Kibble

With a background in sports science and experience as a personal trainer, Jonathan takes his knowledge from the health and fitness industry and applies it to improving the health of Vitality members.

6. Swimming can boost stamina and endurance

I’m not one for long, marathon-level exercise but I would like more stamina. In the pool, I tried to keep stoppage to a minimum and maintain more of a constant, steady flow to meet my minimum target of one kilometre (40 lengths in my 25m pool) without feeling too puffed out.

To increase your stamina and endurance, Quinn suggests that time and effort are key. He says, “You need to practice your technique so regular swim sessions will be beneficial for new swimmers to achieve cardiovascular adaptation before moving on to higher intensities or longer durations.”

Aside from a couple of evenings of interrupted flow (in a public pool you have to accept you won’t always have the luxury of a lane to yourself), I found myself swimming further, more easily as the week progressed. Pacing my breathing with my strokes helped leave me with fewer ‘out of breath’ moments. Studies from the University of Belgrade have also shown that swimming is great for increasing lung capacity and efficiency – something that will benefit me in other types of exercise.

As Quinn explains, being able to swim further for longer requires practice, so while my ‘swim week’ is too short to see noticeable improvements, I feel I’m heading in the right direction.

The bottom line

I certainly enjoyed indulging my love of swimming every evening (mood booster? Tick!), but I must admit that on a couple of evenings, collapsing on the sofa seemed more tempting. Outside of the workout itself, simply “going swimming” takes effort and, much like any other kind of exercise, it's getting out of the door that's the hardest part about swimming every day. Travelling to the pool, changing in/out of your swimwear, thoroughly rinsing the chlorine out of everything, etc, etc. Very few of us have our own pool either - where many people choose to invest in a running machine, indoor cycling kit, or a yoga mat and workout app if that's their chosen activity - so it’s not something you can do from home. 

But every time I got into the water, I forgot about all of that. The pool environment is a very immersive experience, so it helps you get into a different headspace than when you’re at home or even in a regular fitness class. It also meant I was spending at least an hour or more completely screen-free during my evening. As we know, blue light-emitting devices disrupt our sleep patterns, so this can only be a good thing. 

While I didn't experience any magic changes in my sleep routine, overall, my week of nightly swimming was hugely positive. It reminded me to make more time for this water-based exercise that I love and is so complementary to the rest of my fitness routine. Sometimes the best workouts are those where you feel most ‘at home’ – and for me, that’s swimming. But if I go swimming more often, I need to learn from my final observation – a daily dunking in chlorine means I also have to invest in some intensive moisturisers for my hair and skin!

Kerry Law
Freelance Writer

Kerry is a freelance writer covering health, fitness and wellbeing. With bylines in several national publications alongside woman&home - including Stylist, Red, Metro, Good Housekeeping and more. She has written about the latest news and trends in exercise, nutrition, mental wellbeing, alternative health, ecotherapy, health tech, relationships...in fact, anything that impacts our bodies and minds. Outside of work, she can be found doing her most important job (parenting) while trying to squeeze in time for exercise and escaping into nature whenever possible.