Dr. Sarah Cimperman, ND

As we settle into autumn and anticipate winter, we tend to spend more of our active time indoors. We go to the gym instead of the park. We take a spinning class instead of a long bike ride. We climb a machine instead of a mountain. Instead of walking on the beach, we walk on the treadmill. Shorter days and colder temperatures do make it more challenging to schedule outdoor activity, but it’s still important as ever. Here are seven reasons to exercise outside whenever you can.

Cleaner Air

According to the Environmental Protection Agency, indoor is “more seriously polluted than the outdoor air in even the largest and most industrialized cities.”1 Just one example is volatile organic compounds or VOCs. These chemicals are used in manufacturing and they escape in the form of gases from thousands of different products including paint, carpet, building materials, office equipment, cleaning products, and fragrances found in air fresheners and scented candles.2 VOCs are up to ten times more concentrated in indoor air than outdoor air2 and studies show they can promote a range of illnesses including metabolic changes associated with diabetes3 and even cancer.4

Vitamin D

Upon exposure to sunlight, our skin turns cholesterol into vitamin D, a key nutrient for several systems in the body including the cardiovascular, neurological, and immune systems. We can’t get too much vitamin D from the sun like we can from supplements, but we can get too much ultraviolet radiation. The UV index is a scale that estimates the risk of harm that the sun’s rays can have on unprotected skin. It’s highest in the summer, especially in the middle of the day. In the winter, the UV index is lower and the sun’s rays are safer, making it an ideal time to be outside.

Regular Rhythm

Besides stimulating the production of vitamin D, exposure to natural sunlight helps regulate our circadian rhythm. Proteins called cryptochromes that detect light’s blue spectrum are highly active in our eyes but they also exist in our skin and they give our bodies information about our environment. The light and dark cycles we’re exposed to dictate the daily rhythm of our bodies, affecting everything from sleeping patterns and hormone levels to the way we store fat. Our modern world is full of artificial light that sends the wrong message and the more we expose ourselves to outdoor light, the easier it will be to maintain a more natural circadian rhythm and a healthy body.

Stronger Eyes

Nearsightedness is a condition in which distant objects appear blurred. Known also as myopia, it can be an inherited condition, when the eyeball is too long or too curved, or it can develop as we age, when the muscles we use for long-distance focusing become weak. People most at risk of developing nearsightedness are those who spend prolonged periods of time looking at close objects, while reading or using computers and other electronic devices. There is also an association of increased myopia risk with low levels of vitamin D,5 so exercising outside helps your eyes in two different ways. It gives you a boost of vitamin D and it’s a good opportunity to use your long distance vision for a prolonged period of time. After all, your eyes need exercise too.

A Real Break

People at the gym may be exercising, but they’re not always taking a break. While they walk, jog, cycle, or climb, they’re busy watching television, shuffling work papers, or reading newspapers, magazines, books, and mobile electronic devices. Being active outdoors forces you to stop multitasking and focus on the present moment, which is a form of mindfulness. Practicing mindfulness has been shown to reduce stress, strengthen memory and focus, increase immune function, and improve emotional health and well-being.6 You can exercise anywhere, but doing it outside is engaging in a way that indoor exercise just can’t duplicate.

Improved Sleep

A study published in Preventive Medicinefound that having regular access to green spaces and other natural areas was associated with better sleep.7 Researchers studied data from the CDC’s Behavioral Risk Factor Surveillance System which surveyed more than a quarter of a million people. They found that those who had regular access to nature slept well most of the time. This group reported fewer than seven nights of poor sleep per month while people without regular access to nature slept poorly twenty-one to twenty-nine nights each month. The association was strongest for men and for people 65 years and older, but other people benefitted too. Access to nature isn’t the only factor affecting sleep quality, but it may be very helpful and there are no negative side effects.

Better Overall Health

Scientists believe that several factors work together to improve overall health in natural environments. Chemicals called phytonicides, released into the air by plants to protect themselves against bacteria and fungi, have been associated with better immune function in humans and lowered high blood pressure.8 Biodiversity in general and certain microorganisms in particular have also been shown to improve immune function.8 The abundance of negative ions can help resolve mood disorders like depression.8 The sights and sounds of nature have been found to improve attention and promote healing.8 They’ve also been shown to dampen the fight-or-flight response and induce the relaxation response,8 making nature an ideal tool for stress management.

SarahCimpermanND_resisedSarah Cimperman, NDis the author of the new book, The Prediabetes Detox: A Whole-Body Program to Balance Your Blood Sugar, Increase Energy, and Reduce Sugar Cravings. She graduated from NCNM in 2002 and has a private practice in New York City. Her expertise has been featured on Fox News and Huffington Post and in Natural Health magazine, Whole Living magazine, and the Well Being Journal, among other publications. Dr. Cimperman also writes two blogs, A Different Kind Of Doctor and The Naturopathic Gourmet.


  1. Environmental Protection Agency. The Inside Story: A Guide to Indoor Air Quality. [Web page]. EPA website. http://www2.epa.gov/indoor-air-quality-iaq/inside-story-guide-indoor-air-quality. Accessed November 9, 2015.
  2. Environmental Protection Agency. An Introduction to Indoor Air Quality: Volatile Organic Compounds. [Web page]. EPA website. http://www2.epa.gov/indoor-air-quality-iaq/volatile-organic-compounds-impact-indoor-air-quality. Accessed November 9, 2015.
  3. Hong YC, Park EY, M. S. Park. Ko JA, Oh SY, Kim H, Lee KH, Leem JH, and Ha EH. Community Level Exposure to Chemicals and Oxidative Stress in Adult Population. Toxicology Letters. 2009;184(2):139-44. http://www.ncbi.nlm.nih.gov/pubmed/19049859
  4. Rumchev K1, Brown H, and Spickett J. Volatile organic compounds: do they present a risk to our health? Reviews on Environmental Health. 2007;22(1):39-55. http://www.ncbi.nlm.nih.gov/pubmed/17508697
  5. Yazar S, Hewitt AW, Black LJ, et al. Myopia is associated with lower vitamin D status in young adults. Investigative Ophthalmology & Visual Science. 2014;55(7):4552-9. http://www.ncbi.nlm.nih.gov/pubmed/24970253
  6. Davis DM and Hayes JA. What are the benefits of mindfulness. [Web page]. American Psychological Association website. http://www.apa.org/monitor/2012/07-08/ce-corner.aspx. Accessed November 11, 2015.
  7. Grigsby-Toussaint DS, Turi KN, Krupa M, Williams NJ, Pandi-Perumal SR, and Jean-Louis G. Sleep insufficiency and the natural environment: Results from the US Behavioral Risk Factor Surveillance System survey. Preventive Medicine. 2015;78:78-84. http://www.ncbi.nlm.nih.gov/pubmed/26193624
  8. Ming Kuo. How might contact with nature promote human health? Promising mechanisms and a possible central pathway. Frontiers in Psychology. 2015;6:1093. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4548093/


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