To find your answer to the question you will have to scroll down to the conclusion; however, I rather see you stay with me until the end.

The days of trashing exercises and different methodologies are gone. We need to empower people to discover on their own and not to rob them of the opportunity to grow. My role as a movement professional and a health coach is to educate, inspire and guide so everybody can make the decision and judgement without feeling to chose the sides. Hopefully, this article will help you with this.


When I did my research, I was immediately drawn in and wanted to sign up to F45. The official website is brilliant - every facility provides supportive music; there are clear and professional video instructions on the screen with even slow motion of selected drills; people "high-fiveing" with smiles on their face; plus a photo carousel of celebrities who joined the F45 studios that go for at least a minute. F45 is the fastest growing group training brand around the world. So, I think they are doing something right.

There is a lot of things we can discuss about training and programming as every person wants to achieve something different; however, these three outcomes below are hopefully indisputable.

1. Sustainability - the ability to sustain what we do for a longer period of time (possibly a life time)

2. Resiliency - the ability to tolerate sudden changes and remain healthy and strong

3. Injury prevention - the ability to live the happy life without physical obstacles

Please keep these in mind as we go through this article. These are your guide in whatever you decide to engage in.


It’s a HIGH-INTENSITY style training with continuous heart rate stimulus ABOVE the anaerobic threshold. If you don't have F45 in your area, you can think of any practice that is high-intensity in nature, and your heart rate hardly drops.

"F" stands for Functional and 45 is the length of the session (circuit style). Every session is mostly unique, so no workout is repetitive. See more here

Every training session is different with variety of programs and exercises. The program changes roughly every two months. The main focus is on Strength and Cardio and occasional Power drills such as sled push, ball slam or agility foot work.

Regarding the human body, there is hardly anything black and white. So before we go more specific I will try to find the middle ground. Without placing this in to good/bad categories I suggest to consider things. 


  • REPETITIVE STIMULUS. We need to repeat things to create specific adaptation, but too much of anything isn’t suitable to our biology nor sustainable. Let’s have a look at some of the repetitive trademarks of any high-intensity training.

    • Repetitive Intensity selection, a typical F45 protocol is 2:1 - 5:1 between the work and rest. This is where you might work hard for 30 seconds and rest for 15. Another typical example is 40 seconds of work followed by 20 seconds of rest, or 60:15, you got it, right? Following only one work:rest scenario such this can lead to Metabolic Inflexibility that can lead to hypertension, obesity, glucose intolerance and/or developing cardio-vascular disease. Decreasing in Heart Rate Variability (HRV) has been linked to all cause mortality (Thayer, J. F., Yamamoto, S. S., & Brosschot, J. F. (2010). Unfortunately, we can’t call this style of training a HIIT which stands for High-Intensity Interval Training, because there is NO interval in it. At IoM we call it HISS, High-Intensity Steady State. The dosage and programming of HISS are  different as well as benefits.

      A repeated exposure to anaerobic training (pressure overload) can result in thickening of posterior wall, concentric heart hypertrophy or thickened septum that can lead to Hypertrophic Cardiomyopathy (HCM).

      A word on Cell Health

    • Due to a HUGE complexity of the cell signalling (I am working so hard to know more about this topic) this statement will be extremely over simplistic, but the more and often you train in high-intensity the quicker your body ages.  There is no coincidence that athletes are "fit" in their 20's 30'as but broken after that. From my experience maybe too much intensity and not enough of the other stuff? Take care of your Mitochondria. 

      Mitochondrial density (MD) - too much of the hard stuff and MD goes down which speeds up the ageing process - low intensity will create more density of Mitochondria (M. Hypoplasia).

    SOLUTION: if your weekly training program includes most of the high intensity training, try to find the way to decrease it and add more variability to your cardio training. Adding both interval training and low intensity training will be beneficial to your HRV.

    1. Repetitive Exercises selection, Almost 75% of the exercises are linear based. Your body is moving forward and backward or up and down. Since we are living in a three-dimensional world, this workout doesn't give us enough bandwidth to deal with odd positions in it. Skin and fascia (fibrous connective tissue) have to be robust and resilient to be able to tolerate forces coming to them from a different angulations under a different speed. They both receive forces and they all can be remodel. We can chose the directions where they will be remodel. The more angulation the more 3D resilient we are (Schleip, R., & Müller, D. G. (2013).

    SOLUTION: moving linearly but also multi-directionally (frontal and transverse plane) can have significant impact on your resiliency and robustness during life and sport performance. Make sure you incorporate some of the multidirectional training (both body-weight and loaded) on top of your F45 session.

  • RESPECT YOUR OCCUPATION. If your living job is mostly sedentary such as accountants and other office workers, drivers, doctors OR mostly stationary such as pharmacists, shop assistants, restaurant staff - I suggest being mindful of how long you have been in one position without any change. In both cases, it will have a significant effect on the outcome. The environment dictates behaviour; behaviour dictates the outcome.

    If only what you do the whole day is being in one position, and then you engage in sudden high- intensity work, no amount of warm-up can help you to avoid injury. F45 is full of aggressive exercises so considering not just your occupation  but also your daily readiness is paramount. Work load, nutrition, hydration, stress level, sleep - they all can and most likely will play a role in your workout.

    SOLUTION:  the day you decide to attend this session try to move regularly during the day OR find a time to sit and rest. One of your main concern (goal) will be body-wide hydration when you are sedentary and resting up your feet and legs when standing. For sedentary folks, keep standing up every 45 minutes for 2 minutes, have a glass or two of water, do a few moves to create circulation and sit back. For standing folks, try to sit as frequently as you can for 1-2 minutes.

    If you are leaving your work stressed, try to take some time to calm down. Take a few deep breaths to normalise your Autonomic nervous system. The more you are stressed the worst you will move and end of the day, exercise is just another form of stress.

  • WARM UP/MOVEMENT PREP. If you don't have the luxury to move throughout the day and adequately prepare for the class, the programming of F45 will challenge your safety. The warm-up length is typically 1-2 minutes which may not be enough for the amount of dynamic exercises. Keep this in mind and be prepared.

    SOLUTION: one of the best strategy I use in my programming is called Rub&Scrub. It is basically a technique to influence the viscosity of our tissue by applying a localise friction (Haynie 2001). SEE VIDEO HERE .

    The idea is to scrub the tight area vigorously for 30 to 60 seconds. The less viscous tissue we have the better we move thus the less risk of injury. Alongside this strategy I would also suggest to move as much as you can shortly prior the session. It can be as simple as dynamic arms circle, driving the pelvis to a different directions, basic squats, hops on the spot or trunk rotations. The key is - keep it dynamic rather than holding in the stretch.

    All this can significantly decrease the risk of potential injury and prepare you for the class.

  • FEMALES FRIENDLY. Oh yes, a big thumbs up for me. I love the idea of women engaging in weights. I know how gyms can be intimidated for them. But again, a high-intensity training done too often and too much, without variability and adequate support of other health pillars like sleep, stress management & nutrition (think low carb) can lead to hormone imbalances and potential Amenorrhea.

  • CULTURE. No one can take away the fact that organisations such as Zumba, CrossFit, Animal Flow, Zuu or F45 provides incredible environment so you feel like a part of family. I really like this. No solution here, it’s amazing.


Let's talk about something related to the intensity of the exercise and the rest interval applied. Read about Fascia here  - Fascia IS paramount to our movement longevity, injury prevention, resiliency and performance. It's, however, vastly underestimated and not well considered in our training programs. We usually train muscles more than anything else. How do we train Fascia? Unfortunately we can’t discuss this question here but for now, please know that conditioning and mainly hydration of this fibrous connective tissue is essential.

ON HYDRATION (Platform by IoM)

  • Dehydrated tissue from extended bouts of inactivity and poor nutrition disrupts the integrity of the connective tissue and reduces its tolerance to force.

  • Static inflammation and lymph creates chronic swelling which can break down muscle and fascia and decrease joint space

  • Thick fluids in our circulatory and lymphatic systems creates sluggish transport of nutrients and waste

Fascia and skin are viscoelastic - they provide elasticity, but also they are shape stabilising. Fascia needs hydration to be healthy. If the fascia is hydrated well enough, muscles can relax and energy is stored. In the end, we don't want muscles work too hard, because they are metabolically active (get quickly fatigue), but fascia is not.

Here’s the problem, if the burst of intensity is too high and mainly the recovery period is too short and repetitive (think 40:20, 30:15, 60:30) fascia becomes dehydrated and it is lacking the stiffness needed for almost everything from walking, running or jumping (over the bench for example😜).

Soft tissue injuries mostly occur with lack of fascia stiffness. Please note that the word “stiffness” is viewed as positive in this case.

If we can create stability of the collagen matrix using proper hydration, muscles can relax more and can isometrically contract. It makes our movement more efficient and less energy expensive. 

SOLUTION: The accurate recognition between continuously elevated heart rate and interval based training is critically important for Fascia health. The most significant difference is the aerobic rest which is vastly missing in high-intensity style training. Add intervals to your training rather than over-doing HISS.


If I did my job well, you should see that the main discussion should not be about F45, Orange Theory or any other high-Intensity programs.

In the end, they are doing a fantastic job to encourage people to be physically active, and this is to me, very positive. You just have to have some prerequisites before you attend F45.

Our main conversation should be about these two main words ; VARIABILITY and DOSAGE. Almost everything related to human body and sustainable health is anchored to them.

Engaging in one training modality for an extended period can have negative consequences down the track. For our cells, our brain, our heart, our muscles, our bones or ligaments.

In a nutshell, lack of variability and inappropriate dosage can affect our longevity and quality of ageing.

What we all have to get better at is self-education, avoid choosing the sides (self believe) and sharing, we need to understand the whole story and genuinely share with as many people as we can.

I am confident that the long-term, safe and effective solution lies in Institute of Motion (IoM) ‘s 4Q Programming Model where we can fit, organise and practice variability. It’s our safety guide (thanks DP).

And if we go back to our TOP 3 outcomes we wish to achieve, lack of variability can decrease sustainability, decrease resiliency and both can lead to increasing the risk of injury.

Lack of variability can have a cascade reaction process affecting our health

Lack of variability can have a cascade reaction process affecting our health


  • Understand METABOLIC FLEXIBILITY and programming for it (more about the workshop here)

  • Respect and mainly consider your daily readiness and chose training intensity appropriately

  • Avoid ideological thinking (eg. this is better than this)

  • Move with load but also without it, linearly and multi-directionally (more about the workshop here)

  • Use maximal load but sub-maximal too

  • Walk long and steady, jog slow but don't forget to sprint short and fast - in other words, bring your heart rate to the maximum (for shorter time) but also keep it low

  • Practice breathing to up regulate parasympathetic tone of ANS and down regulate the sympathetic one BUT understand that acute sympathetic response is vital for us too

  • Combine sitting with standing and so on…

Variability IS Specificity - the more ingredients you add into the funnel the more specific outcome will come out. Teach your body more skills, super-charge your nervous system, expand your motor vocabulary, grow your muscles, stress the bones, lay down collagen...

So, to answer the question if F45 is good for you? The answer is: yes it is and it is not. Do it too often and too much and it can be more detrimental, do it 2x week in conjunction with the other training styles and take care of your self-care and it can be beneficial, sustainable and fun.

Love Jan

It's our ability to be obsessed that creates a risky environment.