Sisu: Unlocking the Ancient Finnish Key for Success in Work, Relationships, and Well-Being

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About a decade ago, in my 30s, I found myself in the middle of a major personal breakdown. Having recently moved to New York City, I was far from family and friends and felt I had reached the end of my mental and physical capacities.

However, it was in that darkness, thousands of miles from home, that I discovered a vital wisdom from my native country of Finland. This primal force, known as sisu, made its existence apparent. Becoming aware of this universal capacity, which Finns have a word for but we all carry within us, has since transformed my actions in key areas such as work, relationships, and handling everyday challenges.

Sisu is a centuries-old word that has no comprehensive direct translation, but it denotes determination, guts, and a kind of embodied fortitude when you feel you have used all your reserves of strength. It denotes the spark of life force that keeps you breathing through near-impossible odds, helps you trust the next heartbeat or take the first step of a journey of a figurative (or literal) thousand miles.

Perhaps this is you when:

You have a business idea that feels out of reach and requires immense effort, but you know you have to take the chance and follow your vision.

You have been up nights on end caring for your young child or a sick spouse, and you still need to unearth strength to work the next day.

You feel you have used up all your possible options, reserves, and ideas. 

You are within miles or minutes from finishing a race or a workout that pushes you to your limits, and you have burned through your energy.

You carry within you a burning unrealized dream (e.g., a book, parenthood, career change) but you’re afraid to take a chance because of previous failures and hurt.

You feel defeated by your trauma and past or by the challenges faced by the world today.

Perhaps you know or have experienced these or other experiences of sitting in a dark, locked room with no doors leading out. Sisu is what pushes you to make a way where there is none. Sisu means digging deeper into your interior to unearth your latent reserves. In 1914, the father of modern psychology, William James (1914, p. 8), whom I discovered thanks to my professor James Pawelski during my Master of Applied Positive Psychology (MAPP) graduate studies, wrote: 

It is evident that our organism has stored-up reserves of energy that are ordinarily not called upon, but that may be called upon: deeper and deeper strata of combustible or explosible material, discontinuously arranged, but ready for use by anyone who probes so deep … Most of us continue living unnecessarily near our surface.

Sisu is a Finnish term for this “deeper strata” James wrote about that will see you through. It is exactly in these deeper-strata moments that you are in fact a breath away from sisu—the primordial life force and intestinal fortitude, whose one job is to not let you perish. 

In my preliminary study on sisu from 2013, for which I analyzed data from 1208 respondents, I define sisu as extraordinary perseverance, action mindset, and latent power that each convey its core essence as something transcendent and deeply embodied rather than just mental (Lahti, 2019). In fact, I soon discovered the need to go beyond survey data to empirically explore sisu in the context of identity, embodiment, and the interplay between individual experiences and broader cultural forces. Autoethnography, a qualitative research methodology used particularly in social sciences, education, and psychology, offers a framework for studying little-understood phenomena from the “inside out.” Embracing the spirit of my inquiry, I devised a research plan that included two daring field experiments to study the phenomenon of exceeding our assumed mental and physical resources. The first experiment, in 2018, involved a 1,500-mile solo ultra-running and cycling expedition across the length of New Zealand in 50 days (I had a crew of one person to support me: drive our van, prepare meals, and help organize events that we did along the way). A year later, the second experiment took me on a field trip to a Kung Fu Academy in rural North China. These experiences profoundly challenged me and offered a deeper inquiry into the experience and determinants of inner strength in the face of challenging moments. Consequently, in my dissertation I ended up describing sisu also through the dimensions of connection, gentleness, and transcendence (Lahti, 2022). Additionally, I explored the use of systems intelligence, developed by two Finnish professors Raimo Hämäläinen and Esa Saarinen (2007; Hämäläinen et al., 2014), to cultivate the constructive expression of sisu in one’s everyday life.

For seven years in a row, Finland has ranked as the happiest country in the world in the Gallup Happiness Index. Being born and raised in Finland, I believe that sisu plays a role in our happiness, well-being, and ability to maintain a resilient mindset. Sisu can be seen in the resolve that has allowed Finns to forge social structures with life-supportive qualities, providing a foundation for equality, safety, and trust. It is in the attitude of seeing things through, even when nobody is watching. However, my early research also describes the dark side of sisu that can turn inner fortitude merciless, cold, and stubborn thus disrupting the psychological safety and creativity required for problem-solving and helping individuals unearth the resources needed for thriving (Lahti, 2013; 2019). Sisu is therefore not a miracle drug. However, when used consciously and for the right reasons, it can indeed be a vital ingredient for success.

So, how can you apply sisu to succeed in your work, relationships, and everyday life? Here are my personal go-to strategies, derived from both research and life experiences. These strategies have helped me navigate self-imposed challenges for personal growth and have empowered me during the trials of healing from trauma.

  1. Have a superordinate prosocial goal. Research by Professor Angela Duckworth (2014) at the University of Pennsylvania proposes that we are more enduring in tough tasks when we don’t simply work for self-focused goals but have a purpose beyond ourselves. As part of researching sisu, I ran several consecutive ultramarathons across New Zealand. While exploring my own limits, the run also inspired action towards building healing family cultures and breaking the silence around interpersonal violence—topics that deeply matter to me and are beneficial to society at large.

    One of the central findings in my dissertation Sisu as Guts, Grace, and Gentleness, is that sisu doesn’t only live within the individual, but it multiplies in the space between people or even in the imagined presence of another person. Sisu increases when we lean in and work together. 

    When you are about to step into a new challenge or need to muster the strength to endure, find a way to connect your efforts to people or a greater goal that matters to you. This could be your spouse or family, or even someone who has passed but still inspires you. You can also find sisu in staying strong for those who are suffering or dismissed in this world—or by being an advocate for planetary preservation.

  2. Train your primal life force. Several studies on placebos show that humans possess hidden resources that they draw from in times of depletion (e.g., Amanzio & Benedetti, 1999; Clark et al., 2000; Pollo et al., 2008; Pollo et al., 2011). The call of sisu, however, is to not rely on stumbling upon these reserves randomly but to be wise, prepare, and make it systematic in your life. I didn’t just show up to attempt to run across a country; I anticipated struggles and adversity, so I trained systematically for two years. Life is like that too, and in that sense, we are all running an ultramarathon of the most significant kind.

    Think of the effort you’ve put into your education, moving up the career ladder, making a family, or pursuing a simple fitness goal. What partially enables this hard work is sisu. It would be unwise to neglect this source of energy without the same kind of commitment and focus. Top athletes don’t believe in luck but know the age-old formula of success and stamina: “The harder I train, the luckier I get.” Just like excellence according to ancient Greek philosophy is a habit, so is sisu. Begin to pay close attention to how certain actions, relationships, dreams, thoughts, and places influence your life force, and focus on those that increase it. Most importantly, notice how your life force increases and decreases because of certain actions, habits, thoughts, and encounters. This, to me, is one of the most important skills missing from the know-how of most modern humans.

  3. Cultivate sisu as a constructive quality. All our lives some of us have been told that to succeed we must be tough and hard. The big discovery from my 1,500-mile journey across New Zealand was that we are more resilient when we are also gentle with ourselves and others, and research in organizational psychology backs this up (e.g., Duarte & Pinto-Gouveia, 2016; Lanaj et al., 2021; Reizer, 2019). Too much sisu links to harmful outcomes in the form of burnout, poor decision-making, reduced work well-being, and harm to our relationships through mercilessness, disconnection, and compromised teamwork. This was also confirmed in the consecutive validation of the sisu scale (Henttonen et al., 2022) that examined sisu in the context of work well-being in Finland. Dr. Barbara Fredrickson’s (2001) research on positive emotions highlights that when we operate from openness toward ourselves and others, this broadens and builds our cognitive repertoire, giving us greater access to our strength and reserves.

    I have witnessed the damage that too much harshness (as opposed to hardiness) can do—in my own life and around me. On the other hand, studying the research-backed benefits of a more compassionate kind of strength, I wrote my first book not only on sisu but on sisu as a constructive force: a gentle power. Gentleness is not about being passive or meek. It is a way of moving forward and leading with a kind, dynamic, and graceful fortitude that builds aliveness, inspiration, and mutual elevation wherever it touches. We will do the hard things and have the hard conversations but with a deep awareness of how we do this.

    Sisu as gentle power is an invitation to personal agency with a deep understanding of our interdependence and the imperative of care for all life—which includes caring for ourselves as well. It means breaking down the barriers we are currently facing as individuals and as a collective, but not at the cost of connection, compassion, and caring. The message of sisu to the world today is that there is more strength in every human than meets the eye—and when used wisely, we can direct our sisu to build a future where having to use sisu for mere survival can give way to building a better world for all.

So, the next time you are facing a breaking point or doubting if you can see something through, remember: The darker the night and the bigger the feeling of resistance and defeat, the closer the fortitude of sisu. This was how I discovered my sisu—both personally and as a research topic—and it’s reflected again and again in the stories of sisu that I have gathered. In fact, I ended up traveling the world for over a decade in search of finding sisu and life force by exploring different cultures and doing hard things. It turns out, sisu was always right within me, and it is within you too. It is in the deep inhale you take in the dead of a cold night—and in the exhale that gives form to the action that follows.

References

Amanzio, M., & Benedetti F. (1999). Neuropharmacological dissection of placebo analgesia: Expectation-activated opioid systems versus conditioning-activated specific sub-systems. Journal of Neuroscience, 19(1), 484–494. https://doi.org/10.1523/JNEUROSCI.19-01-00484.1999

Clark, V. R., Hopkins, W. G., Hawley, J. A., & Burke, L. M. (2000). Placebo effect of carbohydrate feedings during a 40-km cycling time trial. Medicine & Science in Sports & Exercise, 32(9), 1642–1647. https://doi.org/10.1097/00005768- 200009000-00019

Duarte, J., & Pinto-Gouveia, J. (2016). Effectiveness of a mindfulness-based intervention on oncology nurses’ burnout and compassion fatigue symptoms: A non-randomized study. International Journal of Nursing Studies, 64, 98–107. https://doi.org/10.1016/j.ijnurstu.2016.10.002

Duckworth, A., & Gross, J. J. (2014). Self-control and grit: Related but separable determinants of success. Current Directions in Psychological Science, 23(5), 319–325. https://doi.org/10.1177/0963721414541462

Fredrickson, B. L. (2001). The role of positive emotions in positive psychology: The broaden-and-build theory of positive emotions. American Psychologist, 56(3), 218–226. https://doi.org/10.1037/0003-066X.56.3.218

Henttonen, P. ... & Lahti E. E. 2022. A measure for assessment of beneficial and harmful fortitude: Development and initial validation of the sisu scale, HELIYON.

Hämäläinen, R., Jones, R., & Saarinen, E. (2014). Being better better: Living with systems intelligence. CreateSpace Independent Publishing Platform.

Hämäläinen, R. P., & Saarinen, E. (Eds.) (2007). Systems intelligence in leadership and everyday life. Systems Analysis Laboratory. Helsinki University of Technology. https://sal. aalto.fi/publications/pdf-files/systemsintelligence2007.pdf

James, W. (1914). Energies of men. Moffat, Yard and Company.

Lanaj, K., Johnson, R. E., & Wang, M. (2021). Self-compassion in the workplace: Exploring the role of self-compassion in buffering negative outcomes from workplace mistreatment. Journal of Organizational Behavior, 42(2), 168–196. https://doi.org/10.1002/job.2556

Lahti, E. (2013). Above and beyond perseverance: An exploration of Sisu [Unpublished master’s thesis]. University of Pennsylvania.

Lahti, E. (2022). Sisu as guts, grace, and gentleness: A way of life, growth, and being in times of adversity [Unpublished doctoral dissertation]. Aalto University. 

Lahti, E. (2019). Embodied fortitude: An introduction to the Finnish construct of sisu, International Journal of Wellbeing 9(1). https://doi.org/10.5502/ijw.v9i1.672 

Pollo, A., Carlino, E., & Benedetti, F. (2008). The top-down influence of ergogenic placebos on muscle work and fatigue. European Journal of Neuroscience, 28(2), 379-388. https://doi.org/10.1111/j.1460-9568.2008.06344.x

Pollo, A., Carlino, E., & Benedetti, F. (2011). Placebo mechanisms across different conditions: from the clinical setting to physical performance. Philosophical Transactions of the Royal Society, 366(1572), 1790-1798. https://doi.org/10.1098/rstb.2010.0381

Reizer, A. (2019). Bringing self-kindness into the workplace: Exploring the mediating role of self-compassion in the associations between attachment and organizational outcomes. Frontiers in Psychology, 10, Article 1148. https://doi.org/10.3389/fpsyg.2019.01148

About the author | E. Elisabet Lahti, PhD (C’13) is an applied psychology expert and pioneering researcher of sisu. She presents internationally on the applied psychology of inner strength, life force, and conscious leadership, and she is the author of “Gentle Power: A Revolution in How We Think, Lead and Succeed Using the Gentle Art of Sisu.” Born and raised in Finland, Elisabet holds master’s degrees in social psychology and applied positive psychology. You can find more about sisu and find the Sisu Lab podcast at  www.sisulab.com.