We are the most overweight, depressed, medicated and addicted cohort of humans that has ever lived, yet life has never been so good. Clearly something is wrong with modern life, writes Paul Taylor. Fitness professionals have a key role to play in putting things right.
Humans evolved and thrived because we could hunt down prey with the tools we made, ate a range of natural foods from the environment and led highly physical lives necessary for the proper functioning of our bodies and brains.
Now, most of us spend most of our day sitting on our backsides, and more than 50% of our diet is made up of ultra-processed foods that hijack our brain’s rewards systems while making us overweight and sick.
Exposure to cold and heat caused our ancestors to upregulate critical stress response genes which made us more resilient. Now, our thermoneutral environments are making us soft. We used to live in small tribal communities where everyone had a role and purpose. Now we are digitally connected and physically disconnected.
We are the most overweight, depressed, medicated and addicted cohort of humans that has ever lived, yet life has never been so good! Clearly, something is wrong with modern life. We are ancient genomes in a modern world, and it’s not going well.
Since the start of the comfort revolution, we have seen big increases in cardiovascular diseases, but even greater increases in obesity, diabetes, inflammatory conditions, mood disorders, autoimmune conditions and Alzheimer’s disease (and other types of dementia). Our hunter-gatherer genome, which has not changed significantly in the last 45,000 years, requires and expects us to be highly physically active for normal functioning – not optimal functioning, but normal functioning.
As a fitness professional, you will have heard countless times from people who are reluctantly dipping their toes in the waters of exercise, as well as those who flatout refuse to consider doing so, that they don’t enjoy it because it makes them uncomfortable. My response to that is, ‘It’s
supposed to be uncomfortable – that’s precisely why it’s good for you!’ Physical activity is fundamental to our biology, and without high levels of it, we betray our genome. When we are physically active, we live in accordance with our genome, and we see the positive results through improvements in physical and mental health.
When we exercise, we subject the body to low level stress. A lot of people view stress as something that is bad, but scientists have revealed that the good, the bad and the ugly of stress is a better way of thinking about it. The good part of stress is probably best summed up by the philosopher Friedrich Nietzsche, who famously said, ‘What does not kill me makes me stronger.’ Nietzsche was really talking about a process called ‘hormesis’ – although he didn’t know it at the time. This process is summed up by Professor Edward Calabrese as ‘positive, stimulatory responses to low, subtoxic amounts of stress as opposed to adverse effects of high, toxic levels of stress’.
Hormesis has long been recognised as a natural physiological response of biological systems to stress, and recent scientific discoveries have shown it to be a general biological principle at both the cellular level and the overall organism level. Hormesis has been shown to activate a cascade of cellular responses that slow the ageing process and enhance the resilience, health, longevity and reproduction of microbes, plants and animals by preconditioning them to harmful effects of stress. Essentially, hormesis makes you bulletproof – well, almost!
The single most important hormetic stressor that humans benefit from is physical activity or exercise. When you repeatedly expose yourself to physical exercise followed by appropriate recovery, you become bigger, faster, stronger. This hormetic effect is referred to as ‘eustress’ – stress that actually improves you. A by-product of the adaptation to the stress of exercise is that you increase your protection against a whole host of chronic diseases.
There is now compelling evidence that exercise should be prescribed as treatment for 26 different chronic diseases and conditions, from psychiatric diseases like depression and schizophrenia, and neurological diseases like Alzheimer’s and Parkinson’s, to cancers, metabolic diseases like obesity and type 2 diabetes, and musculoskeletal disorders.
Why is exercise capable of benefiting people suffering from these diverse conditions? The first clue to understanding this is that, for the average human, skeletal muscle is the single largest tissue type in the human body. The 640 or so muscles account for between 40 and 50% of the total body weight of people who are not overweight or obese. Skeletal muscle has a huge capacity to adjust its make-up to meet the acute or chronic demands placed on it – this process is called ‘plasticity’.
As a fitness professional, you know that a well-designed resistance training program will increase the size and strength of muscles, and that an endurance training program will enhance the ability to run long distances. These are both examples of positive (or adaptive) plasticity, but it can work the other way, too. Around one-third of skeletal muscle in an immobilised limb can disappear within weeks. This is an extreme example, but adults lose muscle mass at a rate between 3-8% per decade, and it’s not unusual for a 75-year-old to have lost 50% of their overall muscle mass since their twenties. Use it or lose it! You have probably experienced noticeable changes in your own fitness at some point in your life when an injury or other circumstances have resulted in you being unable to exercise at your usual levels for a while. As we age, it gets harder to regain those fitness levels.
However, it’s not just changes in the strength and physical capabilities of your muscles that occur through exercise or inactivity; profound impacts also occur at a cellular, organ and systemic level, because exercise is a very powerful regulator of gene expression.
In 2005, University of Missouri Professor Frank Booth and his team found that every time you exercise, there’s a ‘triphasic response’ of your genes – that’s three positive waves of gene expression changes
Stress response genes
The first wave occurs after you have started exercise and is characterised by a rapid increase in unsurprisingly – stress response genes! These genes, and their associated stress response pathways, are fundamental to the process of hormesis (the good stress), and a subclass of stress response genes called ‘heat shock proteins’ has really beneficial cellular effects. They get released inside your cells when you exercise, look for damaged proteins and then fix them by bending them back into the correct shape. How cool is that? This is important work because damaged proteins often trigger the cell to become dysfunctional or diseased. I like to think of these heat shock proteins as the cellular agents of resilience.
Metabolic priority genes
The second wave occurs when metabolic priority genes respond to particular metabolic stresses induced by exercise, such as low blood glucose. These genes help ensure that important areas of the body, such as the brain, still receive an energy supply even when your muscles are running out of glucose and glycogen. In the long term, the activation of these genes helps to improve your insulin sensitivity and protect you from metabolic diseases.
Mitochondrial enzyme genes
The third wave is of mitochondrial enzyme genes. Mitochondria are essentially the batteries, or generators, of most of your cells. Damaged mitochondria drive premature ageing (think of the Rolling Stones band member Keith Richards!) and disease.
Exercise helps repair damaged mitochondria, and HIIT (high intensity interval training) not only does this but can also induce mitochondrial biogenesis – which basically translates to brand spanking new batteries for your cells!
Another critical finding from this research was that the positive effects of exercise on gene expression last for at least 24 hours. The practical implication of this is that if you have a limited time to exercise during the week (as most people with busy lives do), you shouldn’t spread it over one or two longer sessions; instead, do five- to ten-minute workouts every day (or as many days as possible). That way, you get more consistent improvements at a cellular level. To compensate for the reduced time of these workouts, you up the intensity so that you maximise the ‘bang for your buck’.
Since the work of Frank Booth and his team in 2005, our understanding of the cellular, metabolic and overall health benefits of exercise has advanced enormously. A number of research teams around the world have discovered a class of cellular signalling molecules released by contracting muscle that drive communication at a cellular level, not just within muscle but all around the body and brain. These molecules are called ‘myokines’. Myokines are a type of cytokine – the collective name for the small proteins that play an important role in cell signalling (sending instructions within and between cells to affect their behaviour). Even though they are small, they have massive health benefits. Myokines communicate with:
Endocrine functions are really important for your health. When myokines enter the bloodstream and communicate with bone, fat, liver, pancreas, heart, immune system and brain cells, they induce a range of metabolic benefits.
Science geeks like me get excited about myokines not just because of their positive impact on health, but also because their existence indicates that muscle tissue can no longer be perceived as a ‘dumb’ collection of fibres acted upon by the nervous system. Skeletal muscle must now be viewed as a fully fledged secretory organ, which is a massive change. I could write an entire book on the benefits of myokines, but here are a few superstar benefits:
Modern life may be killing us, but this doesn’t mean we need to go back to the old hunter-gatherer lifestyle. Scientific research is showing us the immense benefits of strategic exercise protocols that can be incorporated into busy lives. Fitness professionals have both the knowledge and the skills to implement these and prevent more people from suffering the fate of death by comfort.
This article is an abridged extract from Death by comfort: How modern life is killing us and what
we can do about it by Paul Taylor, published by Major Street. Click here for details.
Disclaimer: Where Certificate III in Fitness, Cert III/Cert 3, or Fitness Coach is mentioned, it refers to SIS30321 Certificate III in Fitness. Where Certificate IV in Fitness, Cert IV/Cert 4, or Personal Trainer is mentioned, it refers to SIS40221 Certificate IV in Fitness. Where Master Trainer Program™ is mentioned, it refers to Fitness Essentials and SIS40221 Certificate IV in Fitness. Where Master Trainer Plus+ Program™ is mentioned, it refers to SIS30321 Certificate III in Fitness and SIS40221 Certificate IV in Fitness. Where Certificate IV in Massage or Cert IV/Cert 4 is mentioned, it refers to HLT42021 Certificate IV in Massage Therapy. Where Diploma of Remedial Massage is mentioned, it refers to HLT52021 Diploma of Remedial Massage.