Hem » Articles » Health » Li Karlsén Interview

Li Karlsén is a Captain, Coach, and NEM sponsored athlete. After years in the Swedish army, she is now working as the Head of Security for the women’s rights organisation Kvinna till Kvinna as well as taking the world of freediving* by storm. After winning the Swedish championships a few weeks ago, we caught up with her to talk about freediving and how working with NEM empowers her to push her limits harder and smarter.

*Freediving is diving under the water while holding your breath. Competitive freediving includes different disciplines with and without using fins, going for depth (vertical) or length (horizontal).


Li, tell us how your freediving journey began?

I started freediving out of a mix of curiosity and a minor fear of the deep blue sea. I was travelling in Thailand four years ago, when I decided to take a basic course in freediving to face my fears. To be honest, I didn’t really enjoy the first day.  I was overthinking the whole process and my ego was making excuses as to why it was a bad idea to hold your breath, while going upside down into dark and unknown waters. I finally realised that if I wanted to do this, I needed to leave my ego and all the excuses on the beach. When I did, it was the most liberating sensation that I have ever experienced. As of today, I’m still an addict to the freedom that freediving offers.


That sounds like such a great way to start, off the coast in Thailand! But it’s still a big leap to be competing as a professional athlete. Did you always know that you wanted to compete?

It was quite the opposite, I told myself to never compete in freediving when I started. I joined the Swedish Armed Forces almost twenty years ago, where everything you do is ranked and rated, so when I started freediving, I was determined that it would be my way of relaxing instead of continuously performing. But then I discovered that this was a different kind of performance, that the biggest struggles and achievements derive from the inside and not from external factors. I’ve always enjoyed setting up and following benchmarks that enable me to reach my goals, since training for something that you really want keeps you motivated and overrules the stress that comes with pushing outside your comfort zone. With freediving I had to go to the other end, asking myself why I had certain goals to start with.

In 2018 I decided to do my first freediving competition in depth, I was super nervous and almost didn’t go! Mentally I thought that I wasn’t ready for my first competition, since I just experienced a large earthquake that pretty much destroyed the island of Gili Trawangan, where I was supposed to do my training in 2018. Due to this disruption, on my first dive I turned early, which means that I turned around to go back to the surface, before I reached the depth that I had announced. I was disappointed but I realised that no one else cares – it’s all about what I can do on that specific day, and about how well I understand my capabilities at that moment. For the coming dives, I focused more on staying in the present moment and just doing it for myself while having fun of course! I ended up winning the gold medal in one of the disciplines. Winning felt great but meeting and getting inspired by the community of freedivers was the best part. It was also reassuring to see all the security measures around the competitions. It was rigid, and there were so many precautions in place that I felt very comfortable when trying to push myself to the limit.

When I got back to Sweden in 2019, I really wanted to continue freediving, but it’s quite hard here in the North since the sea and lakes are dark and cold all year round. The transition to having to train in the pool was a long and bumpy ride. I missed the ocean, the salty scent, the swim out to the buoy, the sun in your face and the ugly mask tan that comes with it! Looking into tiles, metres after metres, felt quite tame in the beginning. Luckily, I was smart enough to ask for coaching advice from one of the most skilled freedivers in the world, Dean Chaouche. He made me realise that pool training gives you hundreds of hours and kilometres of apnea whereas the ocean is nice, but only enables a couple of shorter dives – or even just one single deeper one before you must recover. The continuity and variability of the pool seasons became soon an enjoyable part of my everyday life.

In 2020, I went to the national pool competition after training for a few months. I was so close to becoming the Swedish champion! But I ended up getting a red card for one of my dives which took me out of the game*. Freediving is not only about diving long or deep, but also showing that you know your absolute limits. When competing you need to do a so-called surface protocol when you have ascended to get a white card. You must look at the judge, connect your index finger with your thumb (like an OK sign) and say with a clear voice that “I’m ok”. By doing this you show the judges that both your left and right hemispheres (brain) are functional and thus oxygenated. Now afterwards I’m happy that I got that red card, since I learned so much more by failing to win, rather than winning but without gaining knowledge on what makes me fail to start with..

* A red card means that the dive was not approved, and in some cases if the diver blacks out it means disqualification from the competition.


What benefits, such as health related, have you seen as a freediving athlete?

As a sport, freediving is very similar to swimming when it comes to the physical benefits. We basically use similar techniques and sprints in terms of pushing forward or down in the water, with or without fins, but while holding our breath. I have extensively increased my anaerobic threshold and my overall mobility that is required for efficient streamling. The awareness of breathing correctly has also improved my cardiovascular capacity, partly due to the type of breathing that we do before and after a dive, which includes breathing with the nose and using the diaphragm.

Apart from the physical benefits the largest gains come from the mental and emotional aspects, if you ask me. Mentally, freediving is quite like scuba diving, when it comes to feeling relaxed under water, even when you’re very deep down below the surface. Just as in scuba diving, we never dive alone. Not just because it’s nice to have a buddy to keep you company, but because of the safety if something should go wrong. A major difference to scuba diving is however that you are completely alone when diving for depth – it’s just you with yourself down there. You do have a buddy that meets you on the ascent, but it’s too dangerous for both scuba divers and freedivers to go down with another diver for that amount of time. That’s where the emotional aspects come in. Just a small hunch of a bad thought will turn into an emotional avalanche that your ego will use to give you a million reasons not to dive, come up, and question why you are doing this at all. Indeed, breath holding in general and especially underwater is unnatural and uncomfortable for humans. But that doesn’t mean that we can’t or shouldn’t do it to discover where our true limits lie.

One thing that I learned “the hard way” in the Army was that you don’t have to feel comfortable to be relaxed. Freediving took this to another level considering the hypoxia and pressures that you’re exposed to. It has made me realize more than ever that I can be in the most uncomfortable place, both mentally and physically, but still feel in control as well as completely free and relaxed. These insights have enabled me to push way outside my comfort zone repeatedly, which is needed to be able to perform at your peak in any environment.


You mentioned that you use a special kind of breathing technique for freediving, what does that mean?

Before a dive we breathe through the nose and use the diaphragm to hypoventilate, i.e. under-breathe, in order to lower pulse, conserve oxygen and keep as much CO2 in the body as possible. This is because CO2 activates the mammalian dive response that helps all mammals to conserve oxygen during a breath hold. In a normal state (not sick, working out or holding your breath) you can’t increase your oxygen level by breathing faster, i.e. hyperventilating or over-breathing. Your oxygen saturation is normally at 95-99%, meaning that breathing without thinking about it – or even breathing slightly less than normal will keep you completely oxygenated.  Hyperventilation is the opposite of hypoventilation, where you exhale too much CO2 and therefore create an imbalance in the circulation that disables the necessary Bohr effect needed to oxygenate your body (1). Tummo breathing, made famous by Wim Hoff, uses hyperventilation and should therefore never ever be used near water. Not even a glass of water, if you ask me, due to the increased risk of fainting caused by the instant cerebral vasoconstriction.

Most of the breath holding training that I use outside the water also includes nostril breathing, such as a variation of pranayama exercises. This is due to the fact that nitric oxide is stored in the nasal cavity and acts as a potent vasodilator when inhaled, meaning that the capillaries in the lungs open up more and allow for more oxygen transfer to occur (2). This allows for better performance!


Did you have any health issues before you started? Have any come up?

No, I didn’t have any major health issues before I started freediving, but I did have old injuries from a serious car accident 15 years ago. Apart from being scarred from second and third degree burns on parts of my body, I have nails and titanium in my left leg from breaking my thigh and calf. This means that I must work a lot on my mobility. Freediving without the fins (DNF/CNF) is like the technique required for breaststroke swimming, and monofin (DYN/CWT) is like the technique for butterfly swimming. So, our disciplines resemble swim training in terms of both mobility and strength and can be considered low impact sports.

The issues and injuries are mostly related to deep diving in terms of the pressure that we’re exposed to. Just by freediving to ten metres (33 feet) the pressure has doubled (2 Bar), which means that all air in your body is half the volume compared to the surface. If you go down too fast and deep for your capability, you risk barotrauma in your ears as well as ruptures in your lungs and airways. We call these injuries “squeezes”. It basically means that you get a flesh wound in your lungs or airways and start coughing blood when you surface. Freedivers have died from this, and it’s one of the reasons to listen to your body, leave your ego on the beach and get proper recovery between the dives. Research shows that we get fluid in our lungs, so called “comets” or “B-lines” by just diving to ten metres, which you recover fast from if you rest a couple of hours after an open water session (3).


What did the process of working with NEM look like?

The first thing we did was to set up goals, focusing on the purpose of working together and what I wanted to achieve. For me, my goal is to find how I can perform 10% better. Working hard and having a high work ethic is the baseline for any athlete, but to break world records you must train smarter and recover faster than your competitors. Since I already had a good foundation in terms of sleeping, training, and eating patterns we broke down this triad into different components to analyse and to work more with.

One part of this analysis was to do tests to determine my health status. We did blood and DNA analyses, and I also used CGM (continuous glucose monitoring). My values were overall good, but since good isn’t enough in this case, we decided that I needed to add, remove, and change a few things. A low hanging fruit was to add some additional supplements, some that I have heard of and others that I didn’t even have a clue existed! My hemoglobin levels are so vital to my performance and I started taking Iron, as well as more Magnesium as it’s essential for muscle relaxation. Apart from optimizing performance, NEM also helped me to customize my supplements according to my genetics, such as taking nicotinamide mononucleotide (NMN) which aids healthy aging, DNA repair and improved immune system function (4).

Parallel to the analyses, NEM also provided me with some wearables to keep track of my training as well as recovery. All the wearables are connected to an application where NEM can track my values, making it easy and efficient to go through my results when we have our bi-weekly check-ins. One of the most useful tools has been the Oura ring. I knew that sleep was important but being able to track the amount of necessary deep sleep and REM, as well as my resting heart rate and HRV was a game changer. The check-ins gave me a chance to properly understand the values that the wearables were showing, as well as to ask nitty gritty questions to the very skilled medical staff at NEM. Improving performance and winning competitions is important and fun indeed, but the most valuable aspect of working together with NEM is my ability to stay healthy, strong, and disease free for a longer time – and hopefully adding additional good years to my life.


What physical health benefits have you seen since starting to work with NEM?

One of long-term goals in working with NEM has been to figure out ways to train smarter and recover faster. Solutions to this came quite early in the process! The support and coaching that I received in terms of twisting my diet according to my “real” needs, as well as continuous analysis of the data from the wearables made huge improvements in terms of how much faster that I could recover, both during the laps and after the sessions. One example of this is how we managed to optimize my performances during the nationals this year, in terms of knowing when to start fasting, how to optimize nutrition before a dive and gain a better grasp of how many hours of recovery that I needed before another max attempt. This analysis was done with data from the CGM, the Oura ring as well information from the various blood tests. It was a trial, and it worked well! During the nationals this year I felt overall much more energized, although this was in the middle of a dark and cold November month in Sweden, where doing four max attempts (one per discipline) within 40 hours is the equivalent of doing a marathon for a sprinter! I’m very happy with my results of course, but mostly with the accomplishment of being able to go from zero to national champion within a year together with NEM.

Even if I’ve always been interested in training and in sports my whole life, I have never had the opportunity to get exercise and health related research and findings for female athletes. There’s pretty much no data related to performance that isn’t done by men, on men and for men. Since NEM has already initiated research deriving from both females and males, I could gain a better understanding of my specific needs as a woman and an athlete with a different hormonal cycle than one that is based on a general male athlete. An example of this was that my training programme was changed to correlate better with my menstrual cycle, mostly since having PMS not only reduces your capacity to perform but also prolongs your recovery time.


Do you think that a partnership with a company like NEM can be beneficial to competing athletes?

Definitely. If I had done this alone it would have taken me a much longer time and wouldn’t have been as fun or as much of a learning journey! I know how my body functions, and there is no need to guess it. I think that there are a lot of benefits in working with NEM for all types of athletes, even those that already have a good “triad” of sleep, exercise, and nutrition.

One thing that stands out with NEM is that they’re not “normal” doctors i.e., today’s medical and health care offers help if you’re already injured, and the system aims to keep you alive – but not to stay well. Don’t get me wrong, I’m forever grateful for the medical and health care that we have in Sweden, not at least after the car accident that almost killed me. But, from my perspective NEM offers what we lack in Western medical care, and that’s proactive care to stay healthy longer in life without needing to go to the hospital to the extent that we do today. You do not have to be an athlete or have advanced training goals to benefit from the services and expertise that NEM offers. If you want to hack into your health and improve yourself, that’s already possible today. It’s like a 21st century version of “becoming a better version of yourself” from the cellular level and up! NEM could be part of your journey to reach your goals.


Glad to hear you like working with us! What do you see as your goals for the next year?

I still miss the ocean a lot, so I would love to go more into deep diving again. Due to the pandemic the plan was to focus on pool 2021 and then go for more depth in 2022. Hopefully this plan will survive the reality, and my training going horizontally will be beneficial when going vertical too. Apart from competing myself, I also run a freediving school, Freedive Nordic, and a training club for kids, young people and adults, Ariel fridykning. One of my goals is to grow the freediving community in the Nordics, giving me more dive buddies, as well as sharing the healthy benefits of the sport.

Since freediving is still just a hobby, I also work full time at the women right’s organisation Kvinna till Kvinna as Head of Security. Unfortunately, none of our regional offices are in freediving friendly areas! For now, I must plan my time well between making the world healthier through sports, and more humane via the humanitarian sector.


Those are a first rate set of goals and we wish you the best of luck with achieving them in the upcoming years! Thank you so much for taking the time to talk to with us today and for sharing your experience about the free diving world and your journey with NEM.

Grace Marshall

Grace Marshall MSc

Nordic Executive Medicine



  1. Hall JE. Guyton and Hall Textbook of Medical Physiology. W B Saunders; 2015. 1264 p.
  2. Cialoni D, Brizzolari A, Samaja M, Bosco G, Paganini M, Pieri M, et al. Nitric Oxide and Oxidative Stress Changes at Depth in Breath-Hold Diving. Front Physiol. 2020;11:609642.
  3. Patrician A, Spajić B, Gasho C, Caldwell HG, Dawkins T, Stembridge M, et al. Temporal changes in pulmonary gas exchange efficiency when breath-hold diving below residual volume. Exp Physiol. 2021 Apr;106(4):1120–33.
  4. Shade C. The Science Behind NMN-A Stable, Reliable NAD+Activator and Anti-Aging Molecule. Integr Med . 2020 Feb;19(1):12–4.