CHAPTER 9

Extra Credit

Noise, Light, and Other Sources of Obesogenic Pollution Sabotaging Your Weight Loss Efforts

Now that we have discussed all of the major factors within your control, we can finish up with some broader, more environment-related topics that can limit your exposure to factors found in the environment that contribute to obesity. Your personal environment consists of where you live and work—in other words, where you spend most of your time. The “built environment” is pretty much what you guess it is—the man-made, physical parts of where we live and work, the cities, towns, roads, parks, transportation systems, all of which affect our levels of stress and physical activity. Generally speaking, the only way you can control your built environment is by choosing where to live. But you can control your personal environment by the choices you make inside your home and, perhaps to some degree, your office.

URBAN AIR POLLUTION

Los Angeles International Airport (LAX) is about forty miles from my home in Irvine (between forty minutes and four hours away, depending on traffic). When ranked by daily takeoffs and landings, LAX is the fourth-busiest airport in the world, behind Hartsfield-Jackson Atlanta International, Chicago’s O’Hare International, and Dallas/Fort Worth International.²³⁵ LAX averages more than one takeoff or landing per minute, and it is much busier during some parts of the day. My wife grew up in the Westchester neighborhood of Los Angeles, a mile or two from both the very busy 405 Freeway and LAX. When we started dating, and I experienced the house-shaking noise of a nearby takeoff for the first time, I started to wonder what health consequences were associated with living so close to major sources of noise and air pollution.

It is reasonable to think that living near a bustling airport will bring associated air-quality issues. The ultrafine sulfur dioxide, nitrogen oxide, and other toxic particles that are created from the condensation of hot exhaust vapors do not stay confined to the local area. They fan out for miles and can affect anyone breathing that air. These particles can embed themselves deep inside the lungs and then enter the bloodstream. Whether or not they are obesogenic remains to be determined conclusively, but the inflammation that they cause is suspected of worsening many lung conditions, such as asthma and chronic obstructive pulmonary disease (COPD), and of contributing to the development of heart disease. Researchers at the Keck School of Medicine at the University of Southern California have been studying the effects of air pollution on health for many years. In a 2014 paper, they showed that air pollution from LAX affects residents up to ten miles away and concluded that the impact of LAX plane traffic on air quality was so bad that “LAX should be considered one of the most important sources of [particulate matter] pollution in Los Angeles.”²³⁶ To put this into perspective, the researchers calculated that it would take between 174 and 491 miles of freeway traffic, which is about 20 to 50 percent of the highways in Los Angeles County, to match the levels of pollution detected from LAX.

A major interest of the Southern California Environmental Health Sciences Center, and its sister, the Southern California Children’s Environmental Health Center, directed by my colleague Professor Rob McConnell, is in understanding the effects of the ubiquitous air pollution in the L.A. basin on the health of its residents. Center researchers have published a series of studies linking the amount of particulate air pollution in a child’s local environment (for example, home and/or school neighborhood) with risk of obesity.²³⁷ Traffic-related air pollution was linked with obesity and BMI in children aged five to eleven years.²³⁸ They examined more than forty-five hundred children living in thirteen different communities across Southern California over four years, measuring height and weight annually, and used various statistical models to estimate and test traffic density and traffic pollution related to BMI growth. They followed the children beginning in kindergarten or first grade over the next four years and found that those exposed to the highest levels of pollution showed an almost 14 percent increase in annual BMI, and this was increased even more if the children were exposed to secondhand tobacco smoke.²³⁹ More research is definitely needed, but what we know is that air pollution from air or street traffic is detrimental to our health and likely to increase obesity.

NOISE POLLUTION

Air pollution from bustling highways and airports is not the only culprit for increased health challenges, including obesity. Noise pollution, especially related to busy airports, has come under scrutiny lately in scientific circles. Recent studies show that people who live near airports are at increased risk for cardiovascular disease—separate from any heightened cardiovascular risks associated from the air pollution. One such study published in the British Medical Journal found that people who lived in the noisiest areas had an elevated risk for stroke, coronary heart disease, and cardiovascular disease, even after adjusting for confounding factors such as ethnicity, social deprivation, smoking, road traffic noise exposure, and air pollution.²⁴⁰ In addition, the response to noise was dose-dependent; the risk was greatest in the 2 percent of the population who experienced the highest levels of noise. In a parallel study, noise near eighty-nine U.S. airports was significantly linked with a higher relative risk of hospital admission for cardiovascular disease in older Medicare recipients.²⁴¹

While you might guess that exposure to constant or high levels of noise acted by interfering with sleep to impair health, this was not the case; the effects of noise were more direct. Chronic noise leads to continual stress on the body, which has repercussions such as higher blood pressure and heart rate, endocrine disruption through the stress hormone cortisol and heightened overall inflammation.²⁴² Dr. Robert Koch was a German physician and microbiologist who isolated the bacteria that caused anthrax and identified the bacteria responsible for cholera and tuberculosis (for which he received the Nobel Prize in Physiology or Medicine in 1905). Koch’s “postulates” were four rules that must be fulfilled to prove that a microbe caused a particular disease. Koch presciently predicted in 1910 that “one day man will have to fight noise as fiercely as cholera and pest.”

The World Health Organization (WHO) quantified the health burden of environmental noise in a recent report.²⁴³ This burden was measured as “disability-adjusted life years,” or the number of years lost because of disability or death. The WHO estimates that each year in Western Europeans, 45,000 years are lost through noise-induced cognitive impairment in children, 61,000 years are lost as a result of noise-induced cardiovascular disease, a whopping 903,000 years are lost owing to noise-induced sleep disturbance, and 22,000 years are lost because of tinnitus (constant ringing sound in the ears). Moreover, while not being a disease per se, noise-induced annoyance decreases quality of life and therefore also causes disability, which the WHO quantified as 587,000 disability-adjusted life years lost in the Western European population.

Now, can we call excessive, chronic noise an obesogen? While noise is not a chemical or something tangible that we can consume or inhale, we can most definitely categorize it as an obesogen—a “built-environment” obesogen. Noise is a by-product of the built environment, and it negatively affects human physiology in ways that can ultimately lead to weight gain. Although elevated stress on the body due to noise is perhaps the major mechanism here, the disruptive effects of noise on sleep are also significant. As we already discussed, sleep disturbances have numerous downstream consequences ranging from metabolic dysfunction to cardiovascular disease, depression, and immune suppression. Put simply, losing out on sleep creates a vicious biological cycle in your body, disrupting its preferred “clock” and making you more prone to many factors that contribute to weight gain. This is why getting plenty of sleep is among the suggestions in this chapter that will help you control your environmental obesogens. Let’s start there.

GET A GOOD NIGHT’S SLEEP AS OFTEN AS POSSIBLE

As we discussed in chapter 5, sleep medicine has come a long way in the past decade. We know now that sleep not only has large effects on metabolism and related hormones that control weight, satiety, appetite, and cravings, but also has a big impact on circadian rhythms—our inner clock that manages those hormones and sense of day/night. The good news is that sleep is a behavior that can be reprogrammed and supported.

Our bodies crave balance and regularity, preferring to sleep on a predictable schedule. Maintaining healthy sleep habits, in fact, is what helps ensure that the body stays homeostatic and firing its hormones on cue. Millions of Americans are chronically sleep deprived and miss out on the quality of sleep that their bodies need consistently to be fully functional and healthy. Either their self-imposed behaviors (for example, staying up too late—I am guilty of this one) prevent sufficient sleep or they suffer from a real disorder that prevents them from achieving restful sleep (as with sleep apnea and insomnia). Here are some ideas about getting a better night’s sleep:

Know your own needs. Everyone has different sleep needs, although most of us would do well to bank between seven and nine hours a night. One good way to determine how much sleep your body wants is to sleep in a dark room and see how long it takes for you to wake up naturally (no alarm). If you cannot do this, here is another approach to determine an optimal wake-up time. For a week, go to bed about 7.5 hours before your usual wake-up time and see if you can wake naturally five to ten minutes before your alarm goes off.²⁴⁴ This number is based on the fact that the average sleep cycle is ninety minutes long and a full night’s sleep includes five full cycles. You might need more or less than 7.5 hours depending on how long your individual cycles last.

Be consistent. Try to go to bed and rise at the same time daily, weekends and holidays included. Although many people try to shift their sleep habits on weekends to make up their sleep deficiency accumulated during the week, this can sabotage a healthy circadian rhythm. While it’s okay to sleep an extra hour when you have the opportunity and feel like you need it, avoid waking up every morning at six thirty a.m. and then sleeping until ten on a weekend. That will throw your body clock off, and with that goes your normal metabolism and hormonal secretions.

Establish calming bedtime rituals. Try to set aside at least thirty minutes before bedtime to unwind and perform tasks that help your body know that bedtime is at hand. Disconnect from stimulating tasks (such as work, being on the computer, or using a cell phone) and engage in activities that are calming, such as taking a warm bath, reading, drinking herbal tea, or listening to soothing music. Stretch or do something relaxing.

Hit the pillow before midnight. Just as our individual sleep needs vary, so do ideal times for going to bed. The best bedtime is when you feel most sleepy before midnight. Non-REM (rapid eye movement) sleep tends to dominate sleep cycles in the early part of the night. Then, as night moves closer to dawn, dream-rich REM sleep begins to take over. Although both types of sleep are important and offer separate benefits, non-REM, slow-wave sleep is deeper and more restorative than REM sleep. Note that your ideal bedtime will likely change as you age. The older you get, the earlier your bedtime will become and the earlier you will naturally wake up.

Clean, cool, quiet, and dark. Keep your bedroom clean and cool (ideal temperature for sleeping is between 60 and 67 degrees Fahrenheit). Sleep in the dark—minimize light sources nearby, including that from an electronic device (see next tip). Consider a sleep mask if it is not possible to black out your environment. Try a sound machine or white noise generator to block out noises from the street if you live in an urban environment.

Minimize blue light from electronics. Nearly all light—whether natural sunlight in origin or artificial from light bulbs, TV screens, computers, and smartphone screens—contains blue wavelengths that are a potent suppressor of melatonin, the hormone needed for sleep, and stimulate the alert centers in the brain—a double whammy on sleep.²⁴⁵ Sleep is not the only negative consequence of blue light at night. In 2015, neuroscientist Anne-Marie Chang and colleagues showed that light-emitting devices such as eReaders caused people using them to take longer to fall asleep owing to reduced sensations of sleepiness, have reduced secretion of the sleep-inducing hormone melatonin, have later timing of their circadian clock (that is, were on a “late schedule”), and be less alert the next morning than people who read paper books.²⁴⁶ Modern light-emitting diodes (LEDs) produce quite a bit of blue wavelengths, and these are ubiquitous in televisions, smartphones, tablets, and computers. Blue light should be avoided for a few hours before bedtime for optimum melatonin production. Use warm wavelengths in your home LED lighting (2700K is good). If you are someone who has persistent problems falling asleep, it might be easier to get your hands on eyeglasses that filter out blue light. Make sure that your clocks, night-lights, dimmers, and so on use red, or “warm glow,” lights rather than blue or green. Red light has the least power to shift circadian rhythm and suppress melatonin. Get an app that changes the color temperature of your screen to avoid blue light, particularly if you like to read in bed as I do. The one I use on my phone and tablet is called Twilight and on the computer is f.lux. Both allow me to adjust the color balance to reduce or eliminate the blue light after a certain time of night that I set.

Mind your medicines and other sources of sleep offenders. Drugs, even the ones we don’t consider prototypical drugs such as coffee and alcohol, do indeed impact sleep. It can take time for the body to process caffeine, so try to have a two p.m. cutoff time if you have difficulty sleeping. Alcohol is a mixed bag with respect to sleep. While alcohol can make you feel sleepy, its effects on the body disturb normal sleep cycles and particularly disrupt the restorative slow-wave sleep. Pharmaceuticals, whether over-the-counter or prescribed, can contain ingredients that impact sleep. For example, many headache remedies contain caffeine. Some cold remedies can have stimulating decongestants (such as pseudoephedrine). Side effects in many commonly used drugs can impact sleep. Be aware of what you are taking, and if they are necessary medicines, see if you can take them earlier in the day when they will least impact sleep.

Consider a sleep study. If you have tried all of these approaches and still fail to get a good night’s sleep and/or find yourself relying on sleep aids indefinitely, you might want to consider a sleep study to rule out other issues such as undiagnosed sleep apnea. This will require that you spend the night in a sleep lab that can monitor and record your sleep. These centers are not as unusual as you might think. Many hospitals large and small offer these services.

The benefits of adequate sleep extend to children as well, and they can never start too early. As with adults, kids need a consistent sleep schedule—to go to bed and wake up at the same time every single day, to maintain calming bedtime rituals, and to avoid stimulating things such as lights, screens, and sugar within bedtime.

Before moving on to the next section, I should add that exercise can also help with sleep. Generally speaking, there is a positive link between the amount of vigorous exercise you get and sleep quality.²⁴⁷ Theories as to why this happens run the gamut from the stress-reducing effects of exercise (so presumably you are less likely to be keyed up about work and your “to-do list” to get to sleep on time) to other changes in body chemistry that positively impact hormonal patterns and the circadian rhythm. For example, a study by the National Sleep Foundation called the Sleep in America poll reported that older respondents (aged fifty-five to eighty-four years) who exercised more frequently had fewer complaints than those exercising less than once per week.²⁴⁸ Similarly, a British study found that higher levels of regular physical activity appeared to be protective against the incidence of chronic late-life insomnia.²⁴⁹ These studies demonstrate a correlation between exercise and sleep, and although they suffer from shortcomings such as the use of questionnaires, sleep diaries, and self-reported feelings of well-being, there is probably enough evidence to suggest that regular exercise should help with sleep.

GET MOVING AND KEEP MOVING

We all know that exercise is good for us for a multitude of reasons. But guess what? You do not have to train for a marathon or join a CrossFit gym. Find something you enjoy doing and do it regularly—it is easier than you might think. As with sleep medicine, exercise physiology has come a long way in my lifetime. There is no end to the number of studies showing how exercise positively impacts the body. When we decide to power walk for thirty minutes in a hilly neighborhood, go breathless in an aerobics class, or swim ten laps in a pool, our physiology changes. Some of the most eye-opening research of late has been the metabolic profiling of fit people. Not only is being physically fit associated with a healthier heart and better physique, but researchers have also identified a host of metabolic changes that occur during exercise.

A sedentary lifestyle is a known behavioral obesogen. Where people go wrong in their thinking about physical activity is that exercise alone will keep you lean (increased exercise will help keep you lean when combined with diet modification) and that you have to engage in a very rigorous routine to gain any benefits from exercise (you do not). The simple truth is that you just need to find something you enjoy so that you will do it regularly. Something that allows you to build/preserve lean muscle mass and maintain some degree of cardiorespiratory fitness. This means that your circulatory and respiratory systems are healthy enough to supply fuel and oxygen during sustained physical activity (such as exercise or sex). I will add that metabolic fitness must also be considered; you cannot be considered “fit” if you have chronic high blood sugar, insulin resistance, diabetes, high cholesterol, or any of the other obesity-related risk factors that are often lumped together and called “metabolic syndrome.”

The definition of fitness has also been influenced by recent research into the effects of prolonged sitting. Studies began to emerge in 2010 showing that prolonged sitting compromises metabolic health and increases the risk of premature death—regardless of age, body weight, or amount of physical activity.²⁵⁰ Peter Katzmarzyk from the Pennington Biomedical Research Center published a provocative study showing that sitting for three or more hours per day led to a two-year decrease in longevity, irrespective of overall fitness or exercise.²⁵¹ This means that an hour-long session on an exercise machine will not necessarily undo all the damage of being sedentary the rest of the day (in front of the computer, commuting, watching TV). Most of that damage is metabolic. When you are immobile, your circulation slows down and your body uses less of your blood sugar. Being motionless also negatively influences blood triglycerides, high-density lipoprotein (the good cholesterol), resting blood pressure, and the satiety hormone, leptin (which tells you when to stop eating). Sitting puts muscles into a sort of dormant state where their electrical activity is diminished. Moreover, the production of lipoprotein lipase, the enzyme that breaks down fat molecules in the blood, is shut down. And your metabolic rate plummets.

Dr. James Levine is an endocrinologist and co-director of Obesity Solutions at the Mayo Clinic and Arizona State University. He jerry-rigged what must have been one of the world’s first treadmill desks in 1999 when he bought a $300 secondhand treadmill from Sears and combined it with a tray table that had a telescoping base made to fit over an elevated hospital bed. Since then he has not only promoted the power of more movement throughout the day, but published extensively on “inactivity studies”—the perils of sitting for prolonged periods. His recent work showed that fidgeting while sitting can confer benefits such as increasing energy expenditure by 20 to 30 percent (although it doesn’t increase heart rate).²⁵²

Beyond separating the exercisers from the non-exercisers, a significant concern should be the general lack of walking, standing, and moving our bodies on a regular basis to counteract all the harm that can result from sitting for the majority of the day (hence Dr. Levine’s endorsement of general fidgeting!). We know that moving routinely throughout the day—even if it is just walking around while talking on the phone, exercising while watching TV, taking the stairs instead of the elevator, using a treadmill desk for simple work tasks, or simply making a point to get up every hour for a five-minute stroll or jog in place—will have positive biological effects to counteract the poison of excessive sitting.

People also fail to appreciate just how valuable muscle mass is to quality of life and the ability to optimize metabolic health. Unlike fat, which stores calories, muscle is a highly active tissue that burns calories. This helps explain why lean, more muscular people tend to burn more calories at rest than do people with higher proportions of body fat. Numerous studies support the positive influence of muscle on a healthy metabolism. For example, researchers at UCLA found that increasing muscle mass to average or above average levels led to improved blood glucose management (that is, better insulin sensitivity and lower risk of prediabetes and diabetes).²⁵³ In particular, the study’s results established that every 10 percent increase in the ratio of skeletal muscle mass to total body weight was associated with an 11 percent reduction in the risk of insulin resistance and a 12 percent drop in the risk of developing prediabetes or diabetes.

Achieving ideal fitness is not required to improve your health. A well-rounded exercise program would be one that builds and maintains fitness and includes cardio work, strength training, and stretching. Each of these activities offers unique benefits that your body needs for peak performance and to positively affect your metabolism and longevity. Plenty of activities can cover these areas, from formal gym classes to at-home routines using streaming video over the Internet. Just be sure not to overdo it if you have not established an exercise routine already. Too much exercise will work against you and you might burn out and become a couch potato again.

For the most part, the benefits of exercise are cumulative. You can engage in short bursts of exercise throughout the day (which can actually help minimize your time spent sitting) or commit to a routine that blocks out an hour or so for your workouts. If you do dedicate a single period of time to your exercise regimen, do not allow yourself to be sedentary the rest of the day:

Break up your sitting time by taking five-to ten-minute breaks every fifty minutes, which is around the average person’s working attention span.

Stand or exercise while watching television.

If you work sitting down at the computer a lot, sit on something wobbly such as an exercise ball or a backless stool that forces you to engage your core muscles. Sit up straight and keep your feet flat on the floor in front of you.

Consider a standing desk so you can alternate between sitting and standing at your workstation.

Fidget more!

There are plenty of ingenious devices and apps (some of which you can download for free on your smartphone) to help you track your movement and exercise habits. Remember, exercise alone cannot make you lean or keep you lean. Exercise is best thought about within the context of keeping an optimal physiology and increasing your chances of living longer.