The Benefits of Exercise
One more thing we should be getting more of.
Following the concept of my sleep post, we’ll take a look at exercise next.
An Unfit Society
It’s still the summer months here in the Northern Hemisphere, which generally means that there’s high pressure to look beach-body ready. At least that’s what we tell ourselves, almost like the halfway checkpoint that alerts us that we haven’t quite kept up with that New Year’s Resolution to get in shape. And no, “round being a shape” isn’t a valid justification for not holding up to those resolutions which probably in no way counts as “new” after it’s 10th iteration.
But that’s a general problem with modern society, which may value the aesthetics of fitness and exercise rather than the overall benefits that fitness can provide to one’s health. Years of infomercials with hyper-fit individuals promising that you can look just like them has bastardized the concept of fitness, and for many has become less approachable and more intimidating.
It’s no wonder that fitness as we see it gets such a bad rep. But the fix to such an approach hasn’t been a return to first principles and examining the overall benefits from physical activity, but to instead argue that “fat is beautiful”, or that fat bodies can also be healthy. This eventually led to the phrase “fat activism” becoming adopted.
We’ve essentially damaged the perception of an activity we all should be engaged in to the point that a societal overcorrection has take place. And that’s causing a huge problem overall.
As a society we are getting more obese, dealing with higher levels of cardiovascular disease and diabetes, and we are more inclined to eat unhealthy junk food- in short, we are getting sicker as a nation.
This makes the current COVID predicament even worse, as worse COVID outcomes are heavily associated with higher BMI numbers.
The CDC1 even corroborated this association in March of 2021 with their own findings in which they correlated COVID outcomes with patient BMI:
With an analysis in their Discussion:
One half (50.8%) of adult COVID-19 patients in this analysis had obesity, compared with 43.1% in the total PHD-SR sample and 42.4% nationally (5), suggesting that adults with COVID-19–associated illness and obesity might commonly receive acute care in EDs or hospitals. The findings in this report are similar to those from previous studies that indicate an increased risk for severe COVID-19–associated illness among persons with excess weight and provide additional information about a dose-response relationship between higher BMI and risk for hospitalization, ICU admission, invasive mechanical ventilation, and death (1,2). The finding that risk for severe COVID-19–associated illness increases with higher BMI suggests that progressively intensive management of COVID-19 might be needed for patients with more severe obesity. This finding also supports the hypothesis that inflammation from excess adiposity might be a factor in the severity of COVID-19–associated illness (3,8).
But this review isn’t about obesity2. Obesity may be a consequence of an unfit, inactive lifestyle, but there’s far more to fitness and exercise than weight alone. It’s why there’s been such a messaging problem within the fitness industry and the rising levels of body dysmorphia3, especially among the young.
Instead, we’ll take a look at all of the benefits associated with exercise. Hopefully by understanding all of the general benefits we may seek out exercise not for the aesthetic Adonis look but to become healthier overall.
For the sake of this post exercise refers to general forms of exercise including aerobic exercise and resistance training. Aerobic exercise includes activities such as running and cycling while resistance training refers to strength training exercises such as weight training. Most studies on exercise tend to look specifically at aerobic exercises, so keep that in mind when examining studies on the benefits of exercise. Also, most studies tend to have different measures for durations of exercise as well, so understand that much of what is being covered here will be rather loose examination.
We also won’t cover everything in detail, so use this information to spur further curiosity into looking at other possible benefits of exercise.
The Benefits of Exercise
If exercise could be marketed by the pharmaceutical industry4 it would probably come in the form of a multivitamin due to all of its benefits. That includes neuroprotection, cardiovascular benefits, immune stimulation, and anti-inflammatory properties. Many of these effects are related, and so some of the information may appear repetitive but is provided to reiterate the importance of exercise on these biological functions.
Exercise improves heart health and reduces mortality
Heart disease is the leading killer of both men and women in the US. Therefore, it makes sense that lifestyle choices that increase cardiovascular health should be prioritized. Exercise is considered to be one of the best ways of improving cardiovascular health and reduce the risk of heart-related illnesses (Adams, V., & Linke, A.5):
Already Hippocrates stated that “Walking is man's best medicine”. Nowadays a plethora of epidemiological evidence obtained from large studies support an inverse and independent association between volume of physical activity and cardiovascular and overall mortality in apparently healthy individuals [[1], [2], [3], [4], [5], [6], [7], [8], [9]].One of the first study documenting that higher physical activity is associated with lower risk for cardiovascular disease (CVD) was Morris and colleagues [10]. In their study they analyzed the incidence of CVD in London bus drives and the conductors and reported that the incidence was much higher in the less active drivers when compared to the more active conductors. Subsequently, three landmark studies performed by Paffenbarger and colleagues based on over 16,000 college alumni provided the first solid evidence in a large cohort that physical activity influences risk of mortality substantially [[11], [12], [13]]. These studies also reported an exercise threshold beyond which health benefits are realized. At least an intensity of about 5–6 METs [Metabolic Equivalents6] with an exercise volume of 1000–2000 kcals/week are recommended [8]. Another important outcome of these studies was that exercise-related health benefits are only evident if physical activity was maintained throughout life. It is even calculated that a reduction of inactivity by 10% or 25% would result in a reduction of ~500,000 or 1.3 million deaths worldwide, respectively [14].
As included in the review by Adams, V., & Linke, A, risk of cardiovascular disease may run independent of genetic factors, as the result of twin studies indicate that an active lifestyle may reduce mortality risk by up to 40%:
Based on the results from the Finnish twin cohort study, where the active twin exhibited a ~40% lower risk of mortality when compared to the sedentary twin, we can conclude that physical activity is associated with lower mortality independent of genetic factors [15].
There’s a few reasons why exercise and fitness may contribute to heart health. Exercise may stimulate the nitric oxide (NO) pathway and change heart vasculature, possibly leading to improved blood flow as well as aid in balancing the production of reactive-oxygen species (ROS) which may cause oxidative damage to the heart and other tissues.
A review from Lavie, et. al.7 provides additional context to these changes in heart structure:
Commonly reported morphologic adaptations associated with chronic aerobic ET [exercise training] is LV [left ventricle] dilation (i.e., increased end-diastolic diameter) and hypertrophy (i.e., increased wall thickness), referred to as ET-induced cardiac remodeling. These morphologic LV adaptations parallel enhanced physiologic function during exercise through: 1) Increased early-diastolic filling secondary to a combination of increased preload and increased myocardial relaxation;10 and 2) Increased contractile strength as captured by advanced imaging techniques, such as tissue Doppler and speckle-tracking imaging.9 While much focus has been directed toward the LV, it is important to note that morphologic adaptations also occur in the right ventricle (RV) that appear to mirror LV adaptations.10
[…]
Repetitive bouts of aerobic ET results in a number of favorable vascular adaptations as well, significantly attenuating deleterious adaptations precipitated by the aging process.15 Measures of arterial stiffness are significantly lower in individuals with a higher aerobic capacity (i.e., cross-sectional analysis) 15,16 as well as individuals who have recently completed an aerobic ET program (i.e., longitudinal analysis). 17 Protection against systemic oxidative stress and inflammation induced by chronic aerobic ET are posited to be primary mechanisms for the observed reductions in arterial stiffness.17 Enhanced endothelium-dependent vasodilation through increased production of nitric oxide (NO) is also a clear aerobic ET benefit,18–20 including in the coronary circulation. 21
In fact, the benefits of exercise on heart health has been proven to be so beneficial that there was a general shift in medicine for those who suffer incidences of acute heart damage.
Previously, it was recommended that patients who suffer acute heart damage should receive weeks of bed rest to recover. However, this protocol began to shift towards encouraging exercise rather than limiting exercise to improve heart function (Villella, M., & Villella, A.8):
The relationship between exercise and cardiovascular diseases changed, evolving from proscription to prescription. In the 1930s the survivors of acute coronary syndromes were advised to rest in bed at least 6 weeks. Nowadays exercise training (ET) is considered class I intervention as a part of a rehabilitation program [1]. Similarly, in the 1980s restriction of physical activity was considered the cornerstone of the treatment of heart failure. Currently ET is a class I intervention in stable patients with heart failure [2]. A number of factors led to this radical change in medical opinion, including progress in knowledge of biology of exercise, of modalities of prescription of exercise and of safety issues, not to mention the demonstration of the effects of multifactorial cardiac rehabilitation services in the prevention of cardiovascular diseases [3].
Interestingly, the inability to perform exercises has itself been used as an indicator of heart disease, such that people who struggle to exercise may either be more susceptible to heart disease or may be suffering from it already.
In short, heart disease is one of the leading killers of Americans and likely people all across the world. The intrinsic association between exercise and heart health should encourage people to consider exercising in order to maintain heart health and reduce the risk of heart disease. For those who already suffer from heart disease, exercise may be considered a prescription for improving acute coronary damage, although one should consult with a medical professional before doing so.
Exercise elicits anti-inflammatory mechanisms
Inflammation has become a buzzword in science, but it’s not without good reason. Inflammation is associated with nearly every malady known to man including cancer, diabetes, Alzheimer’s, depression, obesity… you kind of get the deal.
And it’s likely that chronic inflammation is a major consequence of modernity through higher rates of inactivity and poor eating.
Fitness through aerobic exercise and resistance training is well-known to cause its own inflammation- you are damaging the body after all, which then requires undergoing the proper repair mechanisms that rely on inflammatory biomarkers.
However, exercise may help to attenuate chronic, systemic inflammation caused by other diseases and provide an overall net benefit to our health.
It should be made clear that many studies on fitness and inflammation may be influenced by inflammation associated with inactivity. Therefore, the anti-inflammatory effects of exercise may be due to correction from sedentary inflammation (Petersen, A. M., & Pedersen, B. K.9):
Cross-sectional studies demonstrate an association between physical inactivity and low-grade systemic inflammation in healthy subjects (1, 31, 45, 62, 73, 124, 140, 156) in elderly people (16), as well as in patients with intermittent claudication (143). These correlational data do, however, not provide any information with regard to a possible causal relationship. The finding in two longitudinal studies that regular training induces a reduction in CRP level (31, 73) suggests that physical activity as such may suppress systemic low-grade inflammation.
Regardless, much of this anti-inflammation activity is due in part to the production of interleukin-6 (IL-6). IL-6 itself is a pro-inflammatory cytokine and one of the most important signaling molecules for our immune system and host defenses. However, IL-6 is responsible for signaling of other interleukins which themselves have anti-inflammatory properties:
After exercise, the high circulating levels of IL-6 are followed by an increase in IL-1ra and IL-10, and the latter two anti-inflammatory cytokines can be induced by IL-6 (131).
Therefore, IL-6 induces an anti-inflammatory environment by inducing the production of IL-1ra and IL-10, but it also inhibits TNF-α production, as suggested by in vitro (37) and animal studies (72, 75). In addition, rhIL-6 infusion, which causes an increase in plasma IL-6 mimicking the exercise-induced IL-6 response, inhibited endotoxin-induced increase in plasma TNF-α in humans (127). However, exercise is likely to suppress TNF-α also via IL-6-independent pathways, as demonstrated by the finding of a modest decrease of TNF-α after exercise in IL-6 knockout mice (57). […]
The possibility exists that, with regular exercise, the anti-inflammatory effects of an acute bout of exercise will protect against chronic systemic low-grade inflammation, but such a link between the acute effects of exercise and the long-term benefits has not yet been proven. Given that the atherosclerotic process is characterized by inflammation, one alternative explanation would be that regular exercise, which offers protection against atherosclerosis, indirectly offers protection against vascular inflammation and hence systemic low-grade inflammation.
Further information in regards to exercise and anti-inflammatory properties can be found in one review from Scheffer, D., & Latini, A. 10, as well as another review from Suzuki, K.11
So exercise, through the production and response of IL-6, may lead to lower levels of systemic inflammation. The evidence hasn’t been fully elucidated, but considering that nearly all diseases are involved with inflammation it should encourage the idea of exercise in aiding in many forms of maladies.
In fact, exercise has been recommended and even prescribed for those with neurogenerative disease due to its neuroprotective benefits:
The regular practice of physical exercise is known to be beneficial for the CNS health and function, counteracting age-related cognitive decline and dementia risk in humans and rodents [36,110]. A great body of evidence has shown that exercise improves neurological impairments induced by brain injury and promotes functional recovery by preventing neuronal loss [111]. Moderate physical exercise training has been shown to promote neuroplasticity [112], neurogenesis [113] and neuroprotection [114], in addition to hippocampus-dependent learning and memory [115,116].
And that leads us into our next topic: mental health.
Exercise improves mood and mental health
In recent years there has been a growing cultural awareness with respect to mental health. Mental health is possibly one of the most overlooked aspects of health, yet it is our mental health that is so critical to our behaviors and perception of the world. As the world deals with growing rates of depression and anxiety it should be of value to look into ways in which we can attenuate many of those symptoms.
There’s a strong association between exercise and mental health, with evidence suggesting that there is a dose-dependent association between the two (Smith, P. J., & Merwin, R. M.12):
The concept of habitual PA serving a protective role against the development of mental health conditions is further bolstered by data suggesting that greater amounts of PA are associated with incrementally lower risk of mental health problems. Across various exercise modalities, there appears to be a dose-response association between greater PA and mental health functioning (4), even after accounting for numerous social, medical, and behavioral confounds, such as smoking (OR = 0.67, 95% CI 0.61–0.75) (5). Individuals with moderate or low levels of fitness exhibit a 23% and 47% greater risk of developing a mental health problem when compared to their highly fit counterparts, with additive benefits of aerobic and resistance exercise (6). Taken together, epidemiological evidence provides robust evidence that greater habitual PA associates with better mental health functioning.
There’s a few reasons for these benefits. Exercise may encourage more outdoor time in sunlight, and it could be that sunlight exposure and vitamin D production may improve mood. Exercise as an anti-inflammatory may reduce neuroinflammation, which may attenuate neurodegeneration as well as symptoms of depression and anxiety. Similar to the excerpt above from Villella, M., & Villella, A., exercise may improve neuroplasticity (the ability for the brain’s neural networks to reorganize and grow) as well as neurogenesis (production of neurons).
Many of these neurological changes can be visualized by the map below:
Exercise may also help improve mental health outside of typical biochemical mechanisms. Exercise may help with affect regulation13 or provide for consistent routines that help shape behaviors and lifestyles that lead to better mental outcomes:
Specific behavioral mechanisms linking exercise interventions to mental health include self regulatory skills specific to affect regulation (61, 74) (e.g., tolerating and modulating arousal) and cognition (75) (e.g., exerting cognitive control over behavior, sustaining attention, and flexibly shifting attention and behavioral responses to match environmental demands) (76), which could influence mental health directly and through increased self-efficacy (77). Exercise may also potentiate reward salience through increased engagement in personally meaningful or rewarding activities and reward sensitization, or improved fitness (e.g., feeling more fit, improved body image). Behavioral mechanisms broadly correspond with neurological domains of changes, as summarized in Figure 3.
This has been a general concern due to lockdowns, which is likely to have severe detrimental effects due to lack of exercise and abrupt changes in daily routines. More uncertainty means higher levels of anxiety and decreased mood. Thus, exercise may improve mental health by providing a strict regimen in times of uncertainty, reduce uneven mood swings, and helps reduce extreme feelings of uneasiness.
Overall, physical activity provides a multitude of benefits including ones to mental health.
Can you get too much exercise?
There is such a thing as too much of a good thing when it comes to exercise. Although people are encouraged to get moderate levels of exercise there has been evidence of detrimental consequences from excessive, rigorous exercise. Generally speaking, excessive exercise tends to encompass exercise that occurs for several hours and multiple times a day, usually at the level of athletes.
The reasons for these detrimental effects are similar to what has been previously outlined, except that excessive exercise may override any benefits and may lead to harm instead. For example, the anti-inflammatory effects from exercise may be outmatched by the pro-inflammatory effects from muscle/tissue damage and the release of pro-inflammatory biomarkers. The release of ROS and strain on the heart through continuous, extreme exertion may actually increase the risk of cardiovascular disease rather than attenuate it. An example of this can be seen in the
Lavie, et. al. provides additional reasons for this:
There are many potential adverse effects of EEE [excessive endurance exercise] on cardiac structure and function (Figure 5).119 Acutely, EEE increases markers of myocardial injury, such as cardiac troponin and B-type natriuretic peptide, as well dilation of cardiac chambers, especially the atrium and the RV, and reduction in RV function.119–121 Chronically, there is concern that these levels of EEE can lead to detrimental cardiac remodeling and fibrosis, as well as non-lethal arrhythmias, particularly increased risk of atrial fibrillation, and potentially more lethal ventricular arrhythmias, which have been especially noted with very vigorous EEE in animals, with some suggestion of the same finding in humans.119,120,122,123 Recent studies have also suggested that longer distance runners, despite having more favorable overall CHD risk profiles, may have increased levels of atherosclerosis and CHD.124,125
Although this may seem rather concerning, it is far more likely that people suffer from the detrimental effects of inactivity rather than excessive activity. Nonetheless, it’s important to understand when exercise is being overdone, especially for the aesthetic appeal rather than the general health benefits.
Like everything, exercise is a slow climb towards better health and does not occur overnight. Be careful in understanding when you are overdoing it and burning yourself out rather than gaining any benefits afforded from exercise.
Exercise for better health
Exercise is another one of those things that we can’t appear to get enough of, and when we try to exercise we may be intimidated by marketing tactics that prey on our insecurities and encouraging dangerous forms of body dysmorphia. This may prevent many from attempting to exercise due to self-consciousness and unreachable goals. However, there’s far more to exercise than just looking ripped and attractive. Exercise provides all sorts of physical and mental health benefits, and it should really be those benefits that we focus on.
Here, we highlighted a few ways in which exercise can promote better health. In no ways is this review exhaustive- not even close to being anywhere near the amount of coverage needed to show the benefits of exercise.
But unlike other methods of improving health exercise is one method that doesn’t require any external supplements or material. Just by getting up and walking one can move towards better health- literally! And so we should not be bogged down by the need to have the right gear or the right supplements, but to just start moving.
But for those who may want a more concrete outline, The Mayo Clinic provides one example:
You’re likely to find many other routines and outlines online, but remember that it’s not important to get bogged down in the details but to get started, period.
Oh, and if you were wondering why there was no mention of the immune system here, I’m saving much of that talk for it’s own separate post.
So consider taking steps to start getting active- your health literally depends on it.
If you enjoyed this post and other works please consider supporting me through a paid Substack subscription or through my Ko-fi. Any bit helps, and it encourages independent creators and journalists outside the mainstream.
Kompaniyets L, Goodman AB, Belay B, et al. Body Mass Index and Risk for COVID-19–Related Hospitalization, Intensive Care Unit Admission, Invasive Mechanical Ventilation, and Death — United States, March–December 2020. MMWR Morb Mortal Wkly Rep 2021;70:355–361. DOI: http://dx.doi.org/10.15585/mmwr.mm7010e4external icon.
Remember that obesity is a disease with multiple causes. Inactivity, unhealthy eating, and other reasons may cause one to become obese. It’s important to understand that exercise alone cannot fix obesity, but it is one of multiple approaches that can help reduce weight and improve your health.
Body dysmorphia is a mental disorder that’s characterized by an obsessive need to fix or hide physical flaws. This may include through the use of makeup, plastic surgery, or exercise that attempts to sculpt the most aesthetically pleasing image possible. Social media is a huge driver of body dysmorphia due to the presentation of plastic perfection and the perception of what could be.
Surprisingly, in recent years there’s been a drastic increase in body dysmorphia occurring in young boys and teenagers, likely spurred on by fitness influencers such as those seen on Tik Tok and Instagram. The hyper-masculine appeal may cause teenage boys to become self-conscious, and because of this there is a growing concern of teenage boys abusing anabolic steroids and other compounds to get a bodybuilder’s look. This lead to a term called bigorexia to refer to an obsessive need to get bigger and more muscular, and it’s occurring more frequently among teenage boys. It highlights the fact that body dysmorphia may appear in both sexes, but the presentation is likely to be different between the two.
https://americanaddictioncenters.org/male-eating-disorders/body-dysmorphia
This is aside from all of the gimmicky marketing that has happened with diet supplements, test boosters, and other things that can run in the hundreds of dollars already.
Adams, V., & Linke, A. (2019). Impact of exercise training on cardiovascular disease and risk. Biochimica et biophysica acta. Molecular basis of disease, 1865(4), 728–734. https://doi.org/10.1016/j.bbadis.2018.08.019
In many fitness studies MET may be used as a measure of exercise intensity. MET compares one’s resting metabolic rate to their metabolic rate during exercise, usually with the idea that higher MET values indicate more rigorous exercise. It’s hard to get a definitive definition as many people may define MET among different variables such as oxygen usage or Calories burned per some time of a give exercise. Here’s a straightforward definition I found which should be easy to interpret:
Metabolic equivalents are defined as the caloric consumption of an active individual compared with the resting basal metabolic rate at rest. They are used during EST as an estimate of functional capacity. One MET is defined as 1 kilocalorie per kilogram per hour and is the caloric consumption of a person while at complete rest (i.e., 2 METs will correspond to an activity that is twice the resting metabolic rate). Activities of 2 to 4 METs (light walking, doing household chores, etc.) are considered light, whereas running or climbing can yield 10 or more METs.
Fernando Boccalandro MD, FACC, FSCAI, in Cardiology Secrets (Third Edition), 2010
Lavie, C. J., Arena, R., Swift, D. L., Johannsen, N. M., Sui, X., Lee, D. C., Earnest, C. P., Church, T. S., O'Keefe, J. H., Milani, R. V., & Blair, S. N. (2015). Exercise and the cardiovascular system: clinical science and cardiovascular outcomes. Circulation research, 117(2), 207–219. https://doi.org/10.1161/CIRCRESAHA.117.305205
Villella, M., & Villella, A. (2014). Exercise and cardiovascular diseases. Kidney & blood pressure research, 39(2-3), 147–153. https://doi.org/10.1159/000355790
Petersen, A. M., & Pedersen, B. K. (2005). The anti-inflammatory effect of exercise. Journal of applied physiology (Bethesda, Md. : 1985), 98(4), 1154–1162. https://doi.org/10.1152/japplphysiol.00164.2004
Scheffer, D., & Latini, A. (2020). Exercise-induced immune system response: Anti-inflammatory status on peripheral and central organs. Biochimica et biophysica acta. Molecular basis of disease, 1866(10), 165823. https://doi.org/10.1016/j.bbadis.2020.165823
Suzuki K. (2019). Chronic Inflammation as an Immunological Abnormality and Effectiveness of Exercise. Biomolecules, 9(6), 223. https://doi.org/10.3390/biom9060223
Smith, P. J., & Merwin, R. M. (2021). The Role of Exercise in Management of Mental Health Disorders: An Integrative Review. Annual review of medicine, 72, 45–62. https://doi.org/10.1146/annurev-med-060619-022943
The excerpt uses the term affect regulation, which is our ability to appropriately respond emotionally to outcomes and events. This is closely tied to our cognitive functions, and the argument made in the excerpt is that exercise can improve our ability to react to stressors and modulate our emotions in an appropriate manner. This includes delaying rewards and regulating our emotions.
Note that affect dysregulation may include experiencing mood swings, uneven emotions, or extreme emotional responses to stressors or events.
https://www.traumaandbeyondcenter.com/what-we-treat/affect-regulation/
My favorite exercises are things I do for joy. Dance (cardio), gardening (resistance), walking (mental). My favorite mental exercise (you know, build new neural pathways) is to learn new songs. Going to a gym sucks.
I have been on again/off again during my life. After several years on the couch, I rode an e-bike, and I simply had to have one, it was so much fun (I've always liked riding bicycles as a caveat). Ever since it's kept me in pretty good shape. Depending on what setting you use (or sometimes I just shut off the assist completely), you can get all you want in terms of exercise on one. I also think they will be a large part of mobility going forward.
I have also recently committed myself to being in the sun from 1130-1230 every day (best time for vit D production, a nice tan is a side benefit). I can tell you the days when its cloudy at that time I miss it. I think we were definitely meant to be in the sun!