Alexa Fleckenstein M.D.

My intense dislike of the gym just got a scientific underpinning: A meta-analysis reveals that exercise done outdoors has more benefits that the one indoors. A meta-analysis is not a study from scratch but reviews already existing studies. In this case, researchers tried to figure out if there are benefits to exercise in a natural outdoors environment vs a confined gym. The disadvantage of a meta-analysis is that the original studies might be flawed – in spite that the researchers tried to weed out those studies – and that their flaws get compounded. In this case, the original studies were furthermore hampered by not using objective measurements of wellbeing but “self-reported” statements: People just talked about how much better they felt outdoors than indoors. And so the 833 individuals sound less scientific but gushing when reporting how they are feeling after their exercise in nature: “Compared with exercising indoors, exercising in natural environments was associated with greater feelings of revitalization, increased energy and positive engagement, together with decreases in tension, confusion, anger and depression. Participants also reported greater enjoyment and satisfaction with outdoor activity and stated that they were more likely to repeat the activity at a later date.” I believe them even without a proper study because going to a gym would make me depressed – and I am not a depressed person to start with. On the other hand, when I putter around in the garden, I am suffused by bliss. Working out on my ages-old NordicTrack machine in the basement strengthens my muscles; going cross-country skiing lifts my spirit. Clearly, working out in a gym increases endorphins and makes one feel better. But outside, we have the added benefit of light in our eyes and on our skin – which has been shown to decrease depression and boost vitamin D production. For once, Boston did not have another snow storm today so that I could not fill my outdoor needs by snow shoveling but I hacked away on ice for a good hour – to prepare for the next snowfall which is forecast for this week. Outside, there's also less pollution. Contrary to common assumptions, indoor pollution generally is much higher than outdoor pollution (unless you live directly at a busy highway or near a spewing factory) – thanks to detergents and other cleaning supplies, cosmetics, wood preservatives, paints, varnish and lacquers, drywalls, molds, radon, asbestos, carbon monoxide, copiers, printers, correction fluid, glues and craft materials, wax, permanent markers, adhesives, degreasing products, building materials, upholstery, wall-to-wall carpeting and other floor coverings – to name some. Therefore it is recommended that we aerate each room at least twice a day by pushing the windows open for fifteen minutes. And that we sleep with windows open all night. Asking around, I find that not many people do either. Outside has usually uneven terrain – different from the even floor of a standard gym. The unevenness leads to better muscle workout – without that we notice the extra effort. This lowers blood pressure and might stave off Parkinson's. Another advantage of the great outdoors is the color green: We are hard-wired to love a green landscape because green signals plants that produce oxygen and food for us, and hold precious water in place. Green is soothing to our eyes, and to our minds. There is not much life in eternal ice or the dry desert – green is our life. You can reduce indoor air pollution by having houseplants – heartleaf philodendron, spider plant and ficus are not hard to keep alive. For the benefits of outdoors, let’s not forget the smell of flowers, mowed lawns, freshly turned soil. And the sounds: birds’ songs, rustling wind, lapping waves, babbling brooks – music to our ears. Of course, researchers now call for better studies to measure all that. But you and I have known it all along: Outdoors is better!