"Hope molecules" - Myokines: happiness messengers with physical exercise

If you feel unmotivated or a nagging feeling of low energy - there is one tool that is a game-changer when it comes to experiencing renewal. It does not involve sitting hunched over in an endless scroll of social media nor does it include binge-watching shows. It is physical exercise, and is increasingly considered to increase feelings of joy and pleasure.

If you feel unmotivated, sluggish, or feel as if you're struggling with acute depression - there is one tool that is a game-changer when it comes to experiencing renewal. Although it may be tempting to lay down and commence an endless scroll of social media or binge-watching shows, these activities can negatively impact mood states and sleep patterns. A recent systematic review concluded that binge-watching can worsen feelings of depression, anxiety, stress, and loneliness (Alimoradi et al., 2022). Instead, a powerful suggestion to increase feelings of happiness involves getting up and moving your body. It's physical exercise and specifically involves increasing your heart rate. It's not hard training to meet a certain goal, it is simply moving your body in a way that is enjoyable to you. Personally, this is my go-to tool to pick up my mood and boost creativity, focus, and confidence.

A systematic review from Zhang & Chen (2018) found that physical exercise for as little as 10 minutes was shown to increase happiness levels, and this correlation was shown across various countries. Another review from Basso & Suzuki (2017) found positive associations between physical exercise on stress, mood, and cognitive function. The review noted that after single bouts of exercise there were increases in neurotransmitters such as serotonin (associated with various feeling states such as happiness, pleasure, and euphoria), dopamine (feelings of reward), and increases in endocannabinoids which contribute to the feeling of euphoria such as the 'runners high'. Watch Dr. Suzuki in this TedTalk for a snapshot of her research. Her captivating talks are a surefire way to learn about how brain chemistry changes for the better during physical exercise, including improved cognition.

To move your body with the intention to improve mood and feelings of happiness, it is important to enjoy the movement, elevate your heart rate, and move for at least 10 minutes. This gives your brain time to release good-feeling neurotransmitters which reduce stress levels, increase feelings of reward and pleasure. You don't have to get hung up on exercise protocols, training types, and intensities, simply move your body in a way that you enjoy, period. There are several benefits to this- especially when it comes to work. Physical exercise can improve creativity, increase productivity and lower your stress levels at work. Evidence has shown that happier employees are more productive employees (Oswald, Proto, Sgroi, 2015).

In my previous position in worksite wellness, I witnessed employees' metamorphosis after physical exercise. When I sat at the front desk of the wellness center, I observed the complete transformation of employees from the greeting on the way in the doors and the change in their demeanor on the way out. I would observe them walking out of their fitness class, yoga session, or gym workout smiling and exuding a calmer demeanor. On the way out the door, their smiles were brighter and they would say an appreciative "thank you!!" on the way back to their offices.

Hope molecules-the role of myokines and benefits on mental health

Physical exercise ignites a cascade of physiological processes that can reduce percieved stress and begin to make people feel happier. During skeletal muscle contraction, the muscles synthesize and release signaling molecules, specifically IL-6 myokines. Once released, these tiny molecules travel in the blood and attach to receptors on organ cells such as the liver, gut, pancreas, and also cross the blood-brain barrier and attach to certain brain cells. Myokines have also been referred to as "hope molecules", and in a recent meta-analysis and systematic review, findings suggest that myokines have been found to have anti-depressant effects (Heissel et al., 2023). Myokines also 'talk' with receptors in the body. As muscles contract and release myokines, there are beneficial effects on various metabolic processes, including insulin sensitivity, fat oxidation, reduction in cancer cells, and anti-inflammatory responses throughout the body (Leal et al., 2018).

Persistent low-grade inflammation stems from a range of factors including a sedentary lifestyle, chronic stress (while not all stress is bad- persistent chronic stress increases inflammation markers in the bloodstream and has detrimental consequences on physical functioning), and obesity. Now, not all fat is 'bad' fat; fat serves various functions such as the endocrine function of adipose tissue (creating hormones), insulating organs, providing energy, absorbing fat-soluble vitamins A, D, E, and K, and brown fat (is very thin) provides thermogenesis and can burn white fat (thick and lumpy consistency). However excessive white adipose tissue emits a low-grade inflammation and this is potentially harmful for metabolic functioning. 

Examples of enjoyable physical exercise: Set the tone

One of the keys to success is choosing a physical exercise that is enjoyable. It should be accessible to you and perceived as a good experience. If you're not in the mood for strenuous activity or venturing outside-that is perfectly fine. These days, you can move your body from the comfort of your own home with plenty of variety as exercising at home has never been easier. Ensure you dedicate your time to a session that is free of shame and judgment.

Do what you need to set the tone to enjoy movement and feel accepting of yourself. I always put on music that gets me pumped and feeling strong for training. Music is a huge motivator for me and I've noticed it helps me get through my workouts. On the other hand, when practicing yoga, I sometimes light a candle, turn on my salt lamp, play a yoga playlist, and maybe light incense. These personal preferences contribute to cultivating a soothing atmosphere to comfortably move my body and enjoy my "me time". Another go-to for me is family walks in the forest.

When you feel as if you are struggling, are irritable and just not yourself- try exercising for just 10 minutes and take note of how you feel afterwards. Set this time as part of your self care. When stressful sensations come up, remind yourself that exercise is an option to bring on health effects to elevate your mood and lower percieved stress.

A few tips for enjoying physical exercise for those who struggle with it

  • The key is to move your body, elevate your heart rate, and move for at least 10 minutes. If you only feel like only mustering 5 minutes, then do 5 minutes. Making small steps that are achievable to you is what matters.
  • Put on music that will elevate your mood. Take the time to craft your favourite workout playlist, even craft different playlists for different physical activities. I always have cardio, resistance training, cool-down, and yoga practice playlists ready to go.
  • Want to be productive while you go on a walk? Listen to a podcast where you will learn while getting your much-needed physical exercise. My favourite activity is a brisk walk in the forest with a health science podcast playing in my ear.
  • Exercise outside in a green space if it's accessible to you. Go for a brisk nature walk, jog, or workout at a park. Research has shown walking in green spaces can decrease cortisol, increase serotonin and increase feelings of vitality and restoration. The forest offers a perfect setting for happiness movement sessions.
  • Exercising together as a family is wonderful for bonding and supporting the social and emotional health of your children. Exercising with friends is great too. It is good for persons who prefer the support of others and enjoy the social aspect of meeting up and holding each other accountable.
  • Take part in a physical exercise you enjoy. Either go for a brisk walk in nature with your family or a friend, go to your favourite group exercise class either in-person or online, or work out or dance in your living room in the privacy of your garage-whatever is accessible to you and enjoy. The key here is to increase happiness. Did you come across an 80's inspired cardio class online and kind of feel like trying it? Go ahead! No one is judging, this is YOUR self-care time. 

Let's continue framing the idea of physical exercise as an immune-supportive, metabolic-supportive, and cognition enhancing intervention to live healthier and happier lives. Exercise is medicine and thankfully it's gaining more traction for this function. The practice of physical exercise should not be relegated to a certain physique, extreme training regime, or seen as an arduous task. Rather it is an essential aspect of public health as it is an irrefutable tool in reversing and preventing certain chronic diseases, supporting cognitive function and memory, and supporting mental health. Physical exercise is for everyone, and people should find what fits their needs and lifestyle to increase adherence.

Let's spread the news that physical exercise is an essential lifestyle behaviour that should be encouraged across the lifespan. It should be touted as an accessible tool for health that can increase happiness, confidence, and even social connection.


Alimoradi, Z., Jafari, E., Potenza, M. N., Lin, C. Y., Wu, C. Y., & Pakpour, A. H. (2022). Binge-Watching and Mental Health Problems: A Systematic Review and Meta-Analysis. International journal of environmental research and public health, 19(15), 9707. doi.org/10.3390/ijerph19159707

Basso, Julia & Suzuki, Wendy. (2017). The Effects of Acute Exercise on Mood, Cognition, Neurophysiology and Neurochemical Pathways: A Review. Brain Plasticity. 2. 1-26. 10.3233/BPL-160040. 

Heissel, A., Heinen, D., Brokmeier, L. L., Skarabis, N., Kangas, M., Vancampfort, D., Stubbs, B., Firth, J., Ward, P. B., Rosenbaum, S., Hallgren, M., & Schuch, F. (2023). Exercise as medicine for depressive symptoms? A systematic review and meta-analysis with meta-regression. British journal of sports medicine, bjsports-2022-106282. Advance online publication. doi.org/10.1136/bjsports-2022-106282

Leal, L. G., Lopes, M. A., & Batista, M. L., Jr (2018). Physical Exercise-Induced Myokines and Muscle-Adipose Tissue Crosstalk: A Review of Current Knowledge and the Implications for Health and Metabolic Diseases. Frontiers in physiology, 9, 1307. doi.org/10.3389/fphys.2018.01307

Oswald, Andrew J. , Proto, Eugenio and Sgroi, Daniel. (2015) Happiness and productivity. Journal of Labor Economics, 33 (4). pp. 789-822.

Zhang, Zhanjia & Chen, Weiyun. (2019). A Systematic Review of the Relationship Between Physical Activity and Happiness. Journal of Happiness Studies. 20. 10.1007/s10902-018-9976-0.