"I am the Lorax. I speak for the trees. I speak for the trees for the trees have no tongues," Dr. Seuss's the Lorax said. And perhaps we should all be speaking for the trees, as a new study links the presence of trees with human health.
Specifically, researchers found that people experienced more deaths from heart disease and respiratory disease when they lived in areas where trees had disappeared.
"There's a natural tendency to see our findings and conclude that, surely, the higher mortality rates are because of some confounding variable, like income or education, and not the loss of trees," study researcher Geoffrey Donovan, who is a research forester at the Pacific Northwest Research Station of the U.S. Forest Service, said in a statement. "But we saw the same pattern repeated over and over in counties with very different demographic makeups."
The study, which is published in the American Journal of Preventive Medicine, involved data from 1,296 counties spread over 15 states. Researchers examined how many deaths from heart and respiratory disease occurred over 18 years.
The researchers found an association between areas that had been affected by the emerald ash borer beetle -- which kills trees, leaving areas treeless -- and 15,000 more deaths from heart disease and 6,000 more deaths from respiratory disease.
"This finding adds to the growing evidence that the natural environment provides major public health benefits," researchers wrote in the study.
Past studies on the health effects of nature lean more toward its effects on mental health. For example, 2010 research published in the Journal of Environmental Psychology shows that it helps people to feel more alive.
And another study, in the journal Landscape and Urban Planning, shows that it could actually decrease levels of the stress hormone, cortisol, Prevention magazine reported. A more recent study has also linked spending time in nature with increased creativity.
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Improved Attention And Focus
A small study from the University of Illinois at Urbana-Champaign found that kids with ADHD were <a href="http://www.ncbi.nlm.nih.gov/pubmed/18725656?ordinalpos=6&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum" target="_hplink">able to concentrate better after a 20-minute walk in a park</a> rather than a walk through city or neighborhood streets. "What this particular study tells us is that <a href="http://well.blogs.nytimes.com/2008/10/17/a-dose-of-nature-for-attention-problems/" target="_hplink">the physical environment matters</a>," Frances E. Kuo, director of the university's Landscape and Human Health Laboratory and one of the study's co-authors told <em>The New York Times</em>. "We don't know what it is about the park, exactly -- the greenness or lack of buildings -- that seems to improve attention." <em>Flickr photo by <a href="http://www.flickr.com/photos/quacktaculous/3143079032/" target="_hplink">quacktaculous</a></em>
Greater Likelihood To Keep Exercising
While every little bit of exercise counts, let's be honest: most of us could probably afford to do a little bit <em>more</em>. The <a href="http://www.cdc.gov/physicalactivity/everyone/guidelines/adults.html" target="_hplink">2008 Physical Activity Guidelines for Americans</a> recommend the average adult get two hours and 30 minutes of moderate-intensity cardio every week, plus two or more sessions of strength training. It's all too easy to skimp on workouts. However, a 2011 survey found that exercising outdoors is a reinforcing behavior -- the study found that outdoor exercisers "declared a <a href="http://www.ncbi.nlm.nih.gov/pubmed/21291246" target="_hplink">greater intent to repeat the activity</a> at a later date" than gym-goers.
Lower Risk Of Being Overweight
The fresh air, the sunlight, the scenery, the open space -- there's a lot about being outside that can inspire more activity, especially when contrasted to the beckoning couches and screens of indoor spaces. And the extra movement adds up. A 2008 study found that rates of overweight among children who spent more time outside were <a href="http://www.nature.com/ijo/journal/v32/n11/full/ijo2008171a.html" target="_hplink">27 to 41 percent lower than in kids who spent more time indoors</a>.
Exercise itself is sure to reinvigorate you when you're feeling sluggish, but fresh air can up the effect. A 2009 study from the University of Rochester found that <a href="http://www.intrinsicmotivation.net/SDT/documents/2010_RyanWeinstenEtAl_JEVP.pdf" target="_hplink">just 20 minutes outside</a> can rev you up <a href="http://www.telegraph.co.uk/science/science-news/7803320/20-minutes-outdoors-as-good-as-cup-of-coffee.html" target="_hplink">as much as a cup of coffee</a>, <em>The Telegraph</em> reported. "Often when we feel depleted we reach for a cup of coffee, but this suggests a better way to get energized is to connect with nature," lead author <a href="http://www.psych.rochester.edu/faculty/ryan/" target="_hplink">Richard M. Ryan, Ph.D.</a>, a professor of psychology at the university told the publication. <em>Flickr photo by <a href="http://www.flickr.com/photos/galant/688642298/" target="_hplink">thebittenword.com</a></em>
Faster Healing And Less Pain
A 2005 study of spinal surgery patients found that patients staying on the sunny side of the hospital reported <a href="http://www.psychosomaticmedicine.org/content/67/1/156.abstract" target="_hplink">less pain, less stress and needed less medication</a> for pain than patients housed on the shady side of the building. Of course, recovering from a surgery will temporarily put a damper on most fitness plans, but if sunlight is the key ingredient, an outdoor workout may just boast some of the same benefits for more minor injuries.
Higher Vitamin D Levels
Taking your workout outside is a great (and free!) way to soak up some additional vitamin D. A 2011 study that found vigorous exercisers had higher levels of vitamin suggested that <a href="http://yourlife.usatoday.com/fitness-food/exercise/story/2011-10-04/Vigorous-exercise-boosts-vitamin-D-while-lowering-heart-risk/50660716/1" target="_hplink">outdoor exercise may be the reason why</a>, <em>USA Today</em> reported. It may be especially helpful for people with a few pounds to lose, according to Everyday Health, since overweight people are almost <a href="http://www.everydayhealth.com/fitness/outdoor-exercise-benefits.aspx" target="_hplink">twice as likely to not get enough vitamin D</a>. <em>Flickr photo by <a href="http://www.flickr.com/photos/wonderlane/4775285017/" target="_hplink">Wonderlane</a></em>