It’s no secret that exercise is one of the most important ways to keep our bodies healthy. Aerobic activities like jogging keep our cardiovascular systems healthy. Strength training protects our bones while flexibility exercises reduce our back pains and improve posture.
And yet, we continue to do a whole lot of sitting and lying around our daily lives.
Most of us sit on our commute to work. After which, we spend most of the workday sitting and hunched up in front of our desks before we head home to sit (or even lie!) in front of another screen — the television as we wind down after a long day of work.
With more of us taking on flexible work arrangements after the pandemic forced companies to adapt to more work-from-home friendly work schedules, many of us who used to bike and walk to walk have also found the amount of moving dramatically cut down.
In fact, a study by the Stanford Center on Longevity found that “work-from-home is associated with two more hours per day spent sitting”. In addition, “people who could complete their work entirely from home during the pandemic were more likely to sit more and exercise less than before the pandemic.”
Sedentarism and the Harm it Causes Us
A sedentary lifestyle refers to one where there is an excessive amount of daily sitting or lying combined with little to no regular physical activity.
While it might feel good to be able to sit around and lead a comfortable life without much physical activity, sedentarism leads to a myriad of health issues. With sedentarism comes an increased risk of developing health conditions such as type 2 diabetes, coronary heart disease and high blood pressure.
Furthermore, apart from the detrimental impacts on our physical health, it seems that sedentarism actually has numerous negative effects on our brains as well.
Firstly, it was found that long hours of sitting daily are associated with a thinning of the medial temporal lobe. Containing the hippocampus, the medial temporal lobe is essential to the process of consolidating short-term memory into long-term memory. This region also affects our spatial memory, a crucial component of map reading, and visualization.
Secondly, after studying the lifestyles of almost 9,000 women, researchers also found that individuals who led inactive lifestyles (sitting more than seven hours per day) were three times more likely to develop symptoms of depression when compared to those who followed physical activity guidelines (and spent an average of four hours or less sitting down daily).
However, apart from avoiding these negative effects of sedentary lifestyles, moving and exercising more also brings numerous other benefits to our brain and mental health.
“I always tell my patients, ‘What’s good for the heart is good for the brain,’ […] The goal really is to get the heart rate up, at least for 30 minutes and at least three to four times a week.” ~ Dr. Silky Singh Pahlajani
Moving Releases Helpful Chemicals in the Brain
While we exercise, our bodies release chemicals in the brain to encourage the growth of new blood vessels while keeping brain cells healthy, ensuring their survival.
Amongst the many neurotrophins released, a key protein is the Brain-Derived Neurotrophic Factor (BDNF). This protein plays an essential role in helping preserve newly formed neurons, preventing them from premature cell death. At the same time, apart from protecting neurons, BDNF also binds to the receptors on the synapses, helping to improve the signal strength between the neurons.
While there is no research that proves that low levels of BDNF cause depression, Dr. John Ratey (in his book Spark) pointed out that studies done on depressed individuals found that these depressed individuals all had low levels of this protein, suggesting that there might be a possible correlation.
Furthermore, BDNF release after exercise also helps with learning. In fact, individuals who tried to pick up novel vocabulary after intensive exercise experienced a 20% improvement in their learning abilities.
And it Gets Better if You Exercise Under the Sun
A study conducted to find the relationship between serotonin, sunlight, and the season found that the rate of serotonin production is directly related to the prevailing duration of bright sunlight.
Apart from duration, intensity matters as well. As the luminosity of the sunlight increased, the rate of serotonin production also rose rapidly.
Serotonin (also known as 5-hydroxytryptamine) is actually a neurotransmitter and is known as the natural ‘feel-good’ chemical. This is due to its role as a natural mood stabilizer and its ability to reduce the symptoms of depression.
As such, by increasing the rate of serotonin production, sunlight acts as a natural mood booster, allowing one to feel happier while reducing the negative effects that are often associated with depression.
In fact, in 2018, a study conducted by Chinese researchers found that moderate exposure to sunlight correlates to an improvement in memory and motor learning in mice. While humans might function differently from mice, this study suggests that a similar relationship could be happening for us.
Additionally, results from another study also suggested that exposure to sunlight is associated with the cognitive decline one experiences. In this study, the researchers found that individuals with decreased sunlight exposure experienced a higher probability of cognitive decline. This was especially true for individuals with existing depression.
Apart from serotonin, sunlight plays a key role in helping our bodies synthesize vitamin D. A fat-soluble vitamin, vitamin D promotes calcium absorption (strengthening your bones) while also supporting the immune system.
Besides physical health, vitamin D also has a surprising role in mental health as well. Researchers have found that when one has a vitamin D level of below 20 nanograms per millimeter, the risk of depression is raised by as much as 85 percent when compared to individuals with vitamin D levels of more than 30 nanograms per millimeter).
Studies also suggest that there is a causal relationship between taking vitamin D supplements and an improvement in symptoms for those who suffer from depression. As few foods offer vitamin D naturally, going out into the sun might be the best (and easiest) way to help your body get enough vitamin D.
Exercise Leads to Better Sleep and Improved Mood
In addition to the release of helpful chemicals, exercising helps to ensure that you get a good night’s sleep. Dr. Charlene Gamaldo, a medical doctor at John Hopkins Center for Sleep at Howard County General Hospital, shares that moderate aerobic exercise actually increases the amount of slow wave sleep one gets.
As slow-wave sleep (also known as deep sleep) is the period where the brain and body rejuvenate itself, exercising indirectly works to help your body increase the amount of time it has for recovery. Since sleep is also essential for many important brain functions, being able to fall asleep quickly while enjoying improved sleep quality from exercising helps to ensure that your brain can function well.
And while there is no conclusive research that links low BDNF levels to depression, research has shown that exercise does indeed enhance our mental well-being. After doing 30 minutes of daily treadmill walking for just 10 days, patients with major depressive disorder reported substantial improvement in their mood.
Similarly, researchers have found that individuals who had exercised vigorously and regularly were much less likely to develop depression or an anxiety disorder. With exercise being a proven way to lessen the odds of developing depression, moving more in our daily lives would definitely help maintain our mental health in the long run.
And Sunlights Boosts These Benefits
While exercising bathed in sunlight, the photosensitive cells in our retinas are stimulated by the light in the blue unseen spectrum. These cells directly affect the brain’s hypothalamus region, affecting our biological clock — the circadian rhythm.
By exposing ourselves to regular bouts of sunlight and reducing the amount of blue light received at night, we ensure that melatonin — the chemical produced as it gets darker and help regulates our sleep cycle, is produced as desired, allowing our circadian rhythm to work without disruption.
It should be noted that when the circadian rhythm faces disturbances, our bodies can face “significant physiological and psychological consequences”, increasing the risk of illnesses like cancer and heart diseases.
And even though melatonin is created when the light intensity falls, there is evidence suggesting that shift workers who work through the night (and as such, are less exposed to sunlight) produce less melatonin, suggesting that perhaps, having enough sunlight is key to regular melatonin secretion.
With a disruption in melatonin and the circadian rhythm, one can expect to low sleep quality, possible insomnia and even an increase in the risk of depression.
Moving Keeps Your Brain Young
Exercise also keeps the brain young and healthy. Apart from the hippocampus, exercise helps to strengthen the prefrontal cortex as well. And because these two areas are the “most susceptible to neurodegenerative diseases and normal cognitive decline in aging” (from Wendy Suzuki’s TedTalk), exercise directly helps to ensure that our brains can stay healthy longer.
Furthermore, when the results from 11 different studies were combined, it was found that exercising regularly reduces the risk of dementia by almost 30%. When narrowed down to Alzheimer’s disease, the risk was actually reduced by 45%.
Additionally, when 27 different studies focusing on the relationship between exercise and brain function were reviewed, 26 studies showed clear signs of correlation between physical activity and cognitive performance.
The Final Word
With an overwhelming amount of research that suggests a positive relationship between moving and a healthy mind and body, it will definitely be beneficial for all of us to work out as much as we are able to.
And while we are at it, since moving under the sun can further boost the positive effects, it would be beneficial for us to try to do some of our exercises outdoors and in the sun.
Of course, as UV rays can still cause your skin harm, do keep your direct sunlight exposure short and avoid periods with strong UV radiation (e.g. noon). If you are going to be out in the sun for an extended period of time, protect yourself with sunscreen. And for those with skin conditions, it might be good to ask your doctor for advice before heading out to bask in the sun.