Why being outdoors is good for our health

Being outdoors exposes us to natural, full spectrum light. Natural light benefits us in three important ways: it increases our production of serotonin, it regulates our circadian rhythms, and it improves our eyesight.

• Serotonin is a neurotransmitter that plays a role in mood and social behavior, cognition and learning, appetite and digestion, sleep, memory, and sexual desire and function. The more full spectrum light we’re exposed to, the more serotonin we produce. Serotonin production is one of the reasons why bright light therapy (BLT) is now used to treat seasonal and non-seasonal depression. Serotonin is also a melatonin precursor; it gets converted to melatonin in darkness and helps to regulate our sleep-wake cycle.

• Exposure to natural light each day regulates our circadian rhythms. Circadian rhythms are most often associated with our sleep-wake cycle, but they also affect hormone production, appetite, core body temperature, brain wave activity, cell regeneration, and other biological activities. If you’re looking to improve your sleep, research shows that getting outdoors in the morning is best. Being exposed to natural light or very bright artificial light in the morning advances our circadian clock, stimulating melatonin production earlier in the evening and making it easier to fall asleep at night. Daylight exposure later in the day has not been shown to have the same positive effects on circadian rhythms.

• Exposure to natural light is protective against myopia (nearsightedness), while computer, phone, and TV screens and fluorescent light can cause eye strain. Researchers believe that the ways in which natural light affects vitamin D and dopamine production play a role in eyesight development, and that this is why too little natural light exposure during childhood can lead to nearsightedness .

Being exposed to sunlight makes our skin produce vitamin D. Getting enough vitamin D is essential for overall health. We need vitamin D so that we can absorb calcium, and so that calcium and phosphorus can be used to build our bones. Vitamin D also plays a role in protecting against and possibly helping to treat the following conditions:

• Heart disease and high blood pressure

• Diabetes

• Infections and immune system disorders

• Some types of cancer, such as colon, prostate and breast cancers

• Multiple sclerosis

• Fatigue

• Bone pain

• Muscle weakness, muscle aches, or muscle cramps

• Mood changes, like depression

Being exposed to the sun for about 15-20 minutes three times per week is typically sufficient for our skin to produce the vitamin D that we need. But there are some important factors to keep mind. Vitamin D is produced when our skin is exposed to ultraviolet B (UV-B) radiation from the sun. Depending on where you live, UV-B light may not reach you during certain times of the year. UV-B light is typically most powerful between 10:00am and 3:00pm. Cloud cover and air pollution can decrease the amount of UV-B light that gets through. And the darker your skin, the more sun exposure is needed to produce sufficient vitamin D.

As we know, sun exposure is safest in moderation. You can refer to this chart, known as the Fitzpatrick scale, to see how much exposure is safe based on your skin type. Always wear sunblock if you’ll be exposed to the sun for a long period of time, and make sure to avoid getting sunburns.

Spending time in forests exposes us to phytoncides and enhances human natural killer (NK) cell activity. Natural killer (NK) cells are part of our immune system’s first line of defense, reacting rapidly to infected and dangerous cells, including cancer cells. And what are phytoncides, you ask? They’re antimicrobial compounds that are naturally emitted by trees and other plants. Scientists speculate that one reason forest bathing strengthens the immune system is because of exposure to phytoncides.

To test this theory, Dr. Qing Li put 12 healthy men in hotel rooms overnight for three nights. Phytoncides were produced in the rooms by vaporizing cypress stem oil with humidifiers, and the concentrations of phytoncides were measured. Phytoncide exposure significantly increased natural killer (NK) activity and levels of anti-cancer proteins, and decreased the concentrations of adrenaline and noradrenaline (stress hormones) in urine. This results of study and others that have tested the effects of forest bathing on immune system function indicate that phytoncide exposure and decreased stress hormone levels may partially contribute to increased NK cell activity.

Being near moving water exposes us to high levels of negative ions. If you don’t live near a body of water, you can expose yourself to naturally occurring negative ions by taking a shower or going outside right after it rains. As water breaks up into small droplets, electrons combine with oxygen molecules in the air to form negative-ion clusters.

Scientists have been speculating since the 1950s that negative ions stimulate the relaxation response of the parasympathetic nervous system. A 2005 study found that water-generated negative ions enhance NK cell activity, inhibit the initial formation of cancer, and suppress tumor growth in mice. Other studies have found positive effects of negative ion exposure in treating seasonal affective disorder and chronic depression. While there isn’t a great deal of consistent research on negative ions, it’s a topic that warrants exploration.

Ready for your nature prescription?

If you don’t currently spend much time outdoors, start by aiming for 20 minutes per day. This will get you to the threshold of 2 hours per week that has been found beneficial for overall health, and will likely provide you with enough vitamin D. The stress hormone cortisol also drops significantly after spending just 20 minutes outdoors in a natural environment.

The good news is you don’t need to plan a forest bathing trip to Japan to reap the benefits of going outside. A review of 143 studies found that living near or spending time in “greenspace” like parks was enough to improve health. The researchers found that stress, heart rate, blood pressure, cholesterol, type II diabetes, stroke, hypertension, asthma, heart disease, and cancer were all lower among people who were exposed to greenspace. A study of 345,143 people found that those who lived within 1 km of greenspace had lower rates of 15 of 24 disease clusters, most significantly anxiety and depression. And a study of 31,000 Toronto residents found that having an average of 11 more trees in a city block improved cardiovascular and metabolic health in ways comparable to an increase in annual personal income of $20,000.

Do you want to get outside more, but just can’t figure out how to fit it into your schedule? Start by thinking about ways that you can take your regular daily activities outside, like:

• Eat meals outside

• Take work breaks outside

• Do your workouts outside

• Walk or bike to work (if your work commute is too far, try walking to a local store or restaurant)

• Play with your kids outside

• Grab your laptop and do some work outside

• Take phone or in-person meetings outside

• Relax outside (read, talk with a friend, or even look at your phone!) instead of watching TV indoors

Before long, getting outside will be part of your regular routine. Once you start feeling the immediate boost in mood and energy you get from going outside, you’ll start to look forward to it and even crave it. A quick walk outside can take the place of a cup of coffee (seriously). See you out there!

What really causes muscle cramps?

Stop getting muscle cramps by reducing your baseline level of muscle tension

Whether you’re an athlete or not, if you experience muscle cramps on a regular basis you can reduce and even eliminate them by reducing your resting level of muscle tension.

When we repeat a movement over and over, our nervous system gradually makes it automatic so that we don’t have to consciously think about it anymore. This innate process of developing muscle memory is a survival mechanism: It helps us act quickly in dangerous situations.

Muscle memory is a wonderful thing, because it helps us move through our daily lives efficiently. The downside is that we tend to build up elevated levels of tension in the muscles that we use most often. This results both from messages being sent by our brain to contract the muscles, and from a feedback loop called the gamma loop. The gamma loop operates between the spinal cord and the muscles, quickly and automatically regulating the level of tension in our muscles.

When we repeatedly choose to contract certain muscles, the gamma loop adjusts, gradually increasing the baseline level of tension in these muscles. Muscles with elevated levels of tension are in the “cramp prone state;” it takes fewer muscular contractions and less fatigue to push them over the edge into a cramping state.

The most effective way to reduce the baseline level of muscle tension is with pandiculation. Pandiculation is our nervous system’s instinctive reaction to excess muscle tension. If you’ve ever seen a cat or dog arch their back when they get up from a nap, you’ve witnessed the pandicular response.

Thomas Hanna developed exercises that use the pandicular response to reduce muscle tension (I sometimes refer to his technique as “voluntary pandiculation”). Voluntary pandiculation is a specific way of contracting and very slowly releasing muscles that sends accurate biofeedback to the nervous system about the level of tension in the muscles. The technique of pandiculation allows you to retrain your own nervous system, reducing baseline muscle tension and changing habitual posture and movement patterns.